diff --git a/docs/collection-files.md b/docs/collection-files.md
index 414fd8ea..c4878397 100644
--- a/docs/collection-files.md
+++ b/docs/collection-files.md
@@ -30,6 +30,8 @@ Related documentation:
 
 ### Executables
 
+They represent independently executable actions with documentation and reversibility.
+
 An Executable is a logical entity that can
 
 - execute once compiled,
diff --git a/src/application/Context/ApplicationContext.ts b/src/application/Context/ApplicationContext.ts
index 7829737f..4828947a 100644
--- a/src/application/Context/ApplicationContext.ts
+++ b/src/application/Context/ApplicationContext.ts
@@ -1,6 +1,6 @@
 import type { IApplication } from '@/domain/IApplication';
 import { OperatingSystem } from '@/domain/OperatingSystem';
-import type { ICategoryCollection } from '@/domain/ICategoryCollection';
+import type { ICategoryCollection } from '@/domain/Collection/ICategoryCollection';
 import { EventSource } from '@/infrastructure/Events/EventSource';
 import { assertInRange } from '@/application/Common/Enum';
 import { CategoryCollectionState } from './State/CategoryCollectionState';
diff --git a/src/application/Context/State/CategoryCollectionState.ts b/src/application/Context/State/CategoryCollectionState.ts
index 253a7133..6d37ed8f 100644
--- a/src/application/Context/State/CategoryCollectionState.ts
+++ b/src/application/Context/State/CategoryCollectionState.ts
@@ -1,4 +1,4 @@
-import type { ICategoryCollection } from '@/domain/ICategoryCollection';
+import type { ICategoryCollection } from '@/domain/Collection/ICategoryCollection';
 import { OperatingSystem } from '@/domain/OperatingSystem';
 import { AdaptiveFilterContext } from './Filter/AdaptiveFilterContext';
 import { ApplicationCode } from './Code/ApplicationCode';
diff --git a/src/application/Context/State/Code/Event/CodeChangedEvent.ts b/src/application/Context/State/Code/Event/CodeChangedEvent.ts
index 916483f2..41398093 100644
--- a/src/application/Context/State/Code/Event/CodeChangedEvent.ts
+++ b/src/application/Context/State/Code/Event/CodeChangedEvent.ts
@@ -37,12 +37,12 @@ export class CodeChangedEvent implements ICodeChangedEvent {
   }
 
   public getScriptPositionInCode(script: Script): ICodePosition {
-    return this.getPositionById(script.id);
+    return this.getPositionById(script.executableId);
   }
 
   private getPositionById(scriptId: string): ICodePosition {
     const position = [...this.scripts.entries()]
-      .filter(([s]) => s.id === scriptId)
+      .filter(([s]) => s.executableId === scriptId)
       .map(([, pos]) => pos)
       .at(0);
     if (!position) {
diff --git a/src/application/Context/State/Filter/AdaptiveFilterContext.ts b/src/application/Context/State/Filter/AdaptiveFilterContext.ts
index 902ec523..6ecba461 100644
--- a/src/application/Context/State/Filter/AdaptiveFilterContext.ts
+++ b/src/application/Context/State/Filter/AdaptiveFilterContext.ts
@@ -1,5 +1,5 @@
 import { EventSource } from '@/infrastructure/Events/EventSource';
-import type { ICategoryCollection } from '@/domain/ICategoryCollection';
+import type { ICategoryCollection } from '@/domain/Collection/ICategoryCollection';
 import { FilterChange } from './Event/FilterChange';
 import { LinearFilterStrategy } from './Strategy/LinearFilterStrategy';
 import type { FilterResult } from './Result/FilterResult';
diff --git a/src/application/Context/State/Filter/Strategy/FilterStrategy.ts b/src/application/Context/State/Filter/Strategy/FilterStrategy.ts
index 2bda8de2..2a4a7862 100644
--- a/src/application/Context/State/Filter/Strategy/FilterStrategy.ts
+++ b/src/application/Context/State/Filter/Strategy/FilterStrategy.ts
@@ -1,4 +1,4 @@
-import type { ICategoryCollection } from '@/domain/ICategoryCollection';
+import type { ICategoryCollection } from '@/domain/Collection/ICategoryCollection';
 import type { FilterResult } from '../Result/FilterResult';
 
 export interface FilterStrategy {
diff --git a/src/application/Context/State/Filter/Strategy/LinearFilterStrategy.ts b/src/application/Context/State/Filter/Strategy/LinearFilterStrategy.ts
index bb3bfb04..327bdf80 100644
--- a/src/application/Context/State/Filter/Strategy/LinearFilterStrategy.ts
+++ b/src/application/Context/State/Filter/Strategy/LinearFilterStrategy.ts
@@ -1,7 +1,7 @@
 import type { Category } from '@/domain/Executables/Category/Category';
 import type { ScriptCode } from '@/domain/Executables/Script/Code/ScriptCode';
 import type { Documentable } from '@/domain/Executables/Documentable';
-import type { ICategoryCollection } from '@/domain/ICategoryCollection';
+import type { ICategoryCollection } from '@/domain/Collection/ICategoryCollection';
 import type { Script } from '@/domain/Executables/Script/Script';
 import { AppliedFilterResult } from '../Result/AppliedFilterResult';
 import type { FilterStrategy } from './FilterStrategy';
diff --git a/src/application/Context/State/ICategoryCollectionState.ts b/src/application/Context/State/ICategoryCollectionState.ts
index 8a485679..3d9bdaa5 100644
--- a/src/application/Context/State/ICategoryCollectionState.ts
+++ b/src/application/Context/State/ICategoryCollectionState.ts
@@ -1,4 +1,4 @@
-import type { ICategoryCollection } from '@/domain/ICategoryCollection';
+import type { ICategoryCollection } from '@/domain/Collection/ICategoryCollection';
 import { OperatingSystem } from '@/domain/OperatingSystem';
 import type { IApplicationCode } from './Code/IApplicationCode';
 import type { ReadonlyFilterContext, FilterContext } from './Filter/FilterContext';
diff --git a/src/application/Context/State/Selection/Category/CategorySelectionChange.ts b/src/application/Context/State/Selection/Category/CategorySelectionChange.ts
index a944a3f6..36b7de90 100644
--- a/src/application/Context/State/Selection/Category/CategorySelectionChange.ts
+++ b/src/application/Context/State/Selection/Category/CategorySelectionChange.ts
@@ -1,3 +1,5 @@
+import type { ExecutableId } from '@/domain/Executables/Identifiable';
+
 type CategorySelectionStatus = {
   readonly isSelected: true;
   readonly isReverted: boolean;
@@ -6,7 +8,7 @@ type CategorySelectionStatus = {
 };
 
 export interface CategorySelectionChange {
-  readonly categoryId: number;
+  readonly categoryId: ExecutableId;
   readonly newStatus: CategorySelectionStatus;
 }
 
diff --git a/src/application/Context/State/Selection/Category/ScriptToCategorySelectionMapper.ts b/src/application/Context/State/Selection/Category/ScriptToCategorySelectionMapper.ts
index a856b0ea..a2916926 100644
--- a/src/application/Context/State/Selection/Category/ScriptToCategorySelectionMapper.ts
+++ b/src/application/Context/State/Selection/Category/ScriptToCategorySelectionMapper.ts
@@ -1,5 +1,5 @@
 import type { Category } from '@/domain/Executables/Category/Category';
-import type { ICategoryCollection } from '@/domain/ICategoryCollection';
+import type { ICategoryCollection } from '@/domain/Collection/ICategoryCollection';
 import type { CategorySelectionChange, CategorySelectionChangeCommand } from './CategorySelectionChange';
 import type { CategorySelection } from './CategorySelection';
 import type { ScriptSelection } from '../Script/ScriptSelection';
@@ -23,7 +23,7 @@ export class ScriptToCategorySelectionMapper implements CategorySelection {
       return false;
     }
     return scripts.every(
-      (script) => selectedScripts.some((selected) => selected.id === script.id),
+      (script) => selectedScripts.some((selected) => selected.id === script.executableId),
     );
   }
 
@@ -50,7 +50,7 @@ export class ScriptToCategorySelectionMapper implements CategorySelection {
     const scripts = category.getAllScriptsRecursively();
     const scriptsChangesInCategory = scripts
       .map((script): ScriptSelectionChange => ({
-        scriptId: script.id,
+        scriptId: script.executableId,
         newStatus: {
           ...change.newStatus,
         },
diff --git a/src/application/Context/State/Selection/Script/DebouncedScriptSelection.ts b/src/application/Context/State/Selection/Script/DebouncedScriptSelection.ts
index 79a7dd46..23184f20 100644
--- a/src/application/Context/State/Selection/Script/DebouncedScriptSelection.ts
+++ b/src/application/Context/State/Selection/Script/DebouncedScriptSelection.ts
@@ -2,7 +2,7 @@ import { InMemoryRepository } from '@/infrastructure/Repository/InMemoryReposito
 import type { Script } from '@/domain/Executables/Script/Script';
 import { EventSource } from '@/infrastructure/Events/EventSource';
 import type { ReadonlyRepository, Repository } from '@/application/Repository/Repository';
-import type { ICategoryCollection } from '@/domain/ICategoryCollection';
+import type { ICategoryCollection } from '@/domain/Collection/ICategoryCollection';
 import { batchedDebounce } from '@/application/Common/Timing/BatchedDebounce';
 import { UserSelectedScript } from './UserSelectedScript';
 import type { ScriptSelection } from './ScriptSelection';
@@ -16,7 +16,7 @@ export type DebounceFunction = typeof batchedDebounce<ScriptSelectionChangeComma
 export class DebouncedScriptSelection implements ScriptSelection {
   public readonly changed = new EventSource<ReadonlyArray<SelectedScript>>();
 
-  private readonly scripts: Repository<string, SelectedScript>;
+  private readonly scripts: Repository<SelectedScript>;
 
   public readonly processChanges: ScriptSelection['processChanges'];
 
@@ -25,7 +25,7 @@ export class DebouncedScriptSelection implements ScriptSelection {
     selectedScripts: ReadonlyArray<SelectedScript>,
     debounce: DebounceFunction = batchedDebounce,
   ) {
-    this.scripts = new InMemoryRepository<string, SelectedScript>();
+    this.scripts = new InMemoryRepository<SelectedScript>();
     for (const script of selectedScripts) {
       this.scripts.addItem(script);
     }
@@ -49,7 +49,7 @@ export class DebouncedScriptSelection implements ScriptSelection {
   public selectAll(): void {
     const scriptsToSelect = this.collection
       .getAllScripts()
-      .filter((script) => !this.scripts.exists(script.id))
+      .filter((script) => !this.scripts.exists(script.executableId))
       .map((script) => new UserSelectedScript(script, false));
     if (scriptsToSelect.length === 0) {
       return;
@@ -116,9 +116,9 @@ export class DebouncedScriptSelection implements ScriptSelection {
   private applyChange(change: ScriptSelectionChange): number {
     const script = this.collection.getScript(change.scriptId);
     if (change.newStatus.isSelected) {
-      return this.addOrUpdateScript(script.id, change.newStatus.isReverted);
+      return this.addOrUpdateScript(script.executableId, change.newStatus.isReverted);
     }
-    return this.removeScript(script.id);
+    return this.removeScript(script.executableId);
   }
 
   private addOrUpdateScript(scriptId: string, revert: boolean): number {
@@ -152,24 +152,24 @@ function assertNonEmptyScriptSelection(selectedItems: readonly Script[]) {
 }
 
 function getScriptIdsToBeSelected(
-  existingItems: ReadonlyRepository<string, SelectedScript>,
+  existingItems: ReadonlyRepository<SelectedScript>,
   desiredScripts: readonly Script[],
 ): string[] {
   return desiredScripts
-    .filter((script) => !existingItems.exists(script.id))
-    .map((script) => script.id);
+    .filter((script) => !existingItems.exists(script.executableId))
+    .map((script) => script.executableId);
 }
 
 function getScriptIdsToBeDeselected(
-  existingItems: ReadonlyRepository<string, SelectedScript>,
+  existingItems: ReadonlyRepository<SelectedScript>,
   desiredScripts: readonly Script[],
 ): string[] {
   return existingItems
     .getItems()
-    .filter((existing) => !desiredScripts.some((script) => existing.id === script.id))
+    .filter((existing) => !desiredScripts.some((script) => existing.id === script.executableId))
     .map((script) => script.id);
 }
 
 function equals(a: SelectedScript, b: SelectedScript): boolean {
-  return a.script.equals(b.script.id) && a.revert === b.revert;
+  return a.script.executableId === b.script.executableId && a.revert === b.revert;
 }
diff --git a/src/application/Context/State/Selection/Script/SelectedScript.ts b/src/application/Context/State/Selection/Script/SelectedScript.ts
index c0059f6e..858dbbbb 100644
--- a/src/application/Context/State/Selection/Script/SelectedScript.ts
+++ b/src/application/Context/State/Selection/Script/SelectedScript.ts
@@ -1,9 +1,7 @@
-import type { IEntity } from '@/infrastructure/Entity/IEntity';
 import type { Script } from '@/domain/Executables/Script/Script';
+import type { RepositoryEntity } from '@/application/Repository/RepositoryEntity';
 
-type ScriptId = Script['id'];
-
-export interface SelectedScript extends IEntity<ScriptId> {
+export interface SelectedScript extends RepositoryEntity {
   readonly script: Script;
   readonly revert: boolean;
 }
diff --git a/src/application/Context/State/Selection/Script/UserSelectedScript.ts b/src/application/Context/State/Selection/Script/UserSelectedScript.ts
index 315da002..01b40b38 100644
--- a/src/application/Context/State/Selection/Script/UserSelectedScript.ts
+++ b/src/application/Context/State/Selection/Script/UserSelectedScript.ts
@@ -1,17 +1,16 @@
-import { BaseEntity } from '@/infrastructure/Entity/BaseEntity';
 import type { Script } from '@/domain/Executables/Script/Script';
-import type { SelectedScript } from './SelectedScript';
+import type { RepositoryEntity } from '@/application/Repository/RepositoryEntity';
 
-type SelectedScriptId = SelectedScript['id'];
+export class UserSelectedScript implements RepositoryEntity {
+  public readonly id: string;
 
-export class UserSelectedScript extends BaseEntity<SelectedScriptId> {
   constructor(
     public readonly script: Script,
     public readonly revert: boolean,
   ) {
-    super(script.id);
+    this.id = script.executableId;
     if (revert && !script.canRevert()) {
-      throw new Error(`The script with ID '${script.id}' is not reversible and cannot be reverted.`);
+      throw new Error(`The script with ID '${script.executableId}' is not reversible and cannot be reverted.`);
     }
   }
 }
diff --git a/src/application/Context/State/Selection/UserSelectionFacade.ts b/src/application/Context/State/Selection/UserSelectionFacade.ts
index 7667d983..6fbc12bc 100644
--- a/src/application/Context/State/Selection/UserSelectionFacade.ts
+++ b/src/application/Context/State/Selection/UserSelectionFacade.ts
@@ -1,4 +1,4 @@
-import type { ICategoryCollection } from '@/domain/ICategoryCollection';
+import type { ICategoryCollection } from '@/domain/Collection/ICategoryCollection';
 import { ScriptToCategorySelectionMapper } from './Category/ScriptToCategorySelectionMapper';
 import { DebouncedScriptSelection } from './Script/DebouncedScriptSelection';
 import type { CategorySelection } from './Category/CategorySelection';
diff --git a/src/application/Parser/CategoryCollectionParser.ts b/src/application/Parser/CategoryCollectionParser.ts
index be10a9d0..b7e71420 100644
--- a/src/application/Parser/CategoryCollectionParser.ts
+++ b/src/application/Parser/CategoryCollectionParser.ts
@@ -1,7 +1,7 @@
 import type { CollectionData } from '@/application/collections/';
 import { OperatingSystem } from '@/domain/OperatingSystem';
-import type { ICategoryCollection } from '@/domain/ICategoryCollection';
-import { CategoryCollection } from '@/domain/CategoryCollection';
+import type { ICategoryCollection } from '@/domain/Collection/ICategoryCollection';
+import { CategoryCollection } from '@/domain/Collection/CategoryCollection';
 import type { ProjectDetails } from '@/domain/Project/ProjectDetails';
 import { createEnumParser, type EnumParser } from '../Common/Enum';
 import { parseCategory, type CategoryParser } from './Executable/CategoryParser';
diff --git a/src/application/Parser/Executable/CategoryParser.ts b/src/application/Parser/Executable/CategoryParser.ts
index 88d77a1b..9b4790e3 100644
--- a/src/application/Parser/Executable/CategoryParser.ts
+++ b/src/application/Parser/Executable/CategoryParser.ts
@@ -3,16 +3,14 @@ import type {
 } from '@/application/collections/';
 import { wrapErrorWithAdditionalContext, type ErrorWithContextWrapper } from '@/application/Parser/Common/ContextualError';
 import type { Category } from '@/domain/Executables/Category/Category';
-import { CollectionCategory } from '@/domain/Executables/Category/CollectionCategory';
 import type { Script } from '@/domain/Executables/Script/Script';
+import { createCategory, type CategoryFactory } from '@/domain/Executables/Category/CategoryFactory';
 import { parseDocs, type DocsParser } from './DocumentationParser';
 import { parseScript, type ScriptParser } from './Script/ScriptParser';
 import { createExecutableDataValidator, type ExecutableValidator, type ExecutableValidatorFactory } from './Validation/ExecutableValidator';
 import { ExecutableType } from './Validation/ExecutableType';
 import type { CategoryCollectionSpecificUtilities } from './CategoryCollectionSpecificUtilities';
 
-let categoryIdCounter = 0;
-
 export const parseCategory: CategoryParser = (
   category: CategoryData,
   collectionUtilities: CategoryCollectionSpecificUtilities,
@@ -59,7 +57,7 @@ function parseCategoryRecursively(
   }
   try {
     return context.categoryUtilities.createCategory({
-      id: categoryIdCounter++,
+      executableId: context.categoryData.category, // arbitrary ID
       name: context.categoryData.category,
       docs: context.categoryUtilities.parseDocs(context.categoryData),
       subcategories: children.subcategories,
@@ -166,10 +164,6 @@ function hasProperty(
   return Object.prototype.hasOwnProperty.call(object, propertyName);
 }
 
-export type CategoryFactory = (
-  ...parameters: ConstructorParameters<typeof CollectionCategory>
-) => Category;
-
 interface CategoryParserUtilities {
   readonly createCategory: CategoryFactory;
   readonly wrapError: ErrorWithContextWrapper;
@@ -179,7 +173,7 @@ interface CategoryParserUtilities {
 }
 
 const DefaultCategoryParserUtilities: CategoryParserUtilities = {
-  createCategory: (...parameters) => new CollectionCategory(...parameters),
+  createCategory,
   wrapError: wrapErrorWithAdditionalContext,
   createValidator: createExecutableDataValidator,
   parseScript,
diff --git a/src/application/Parser/Executable/Script/ScriptParser.ts b/src/application/Parser/Executable/Script/ScriptParser.ts
index d7be9d0c..bad08345 100644
--- a/src/application/Parser/Executable/Script/ScriptParser.ts
+++ b/src/application/Parser/Executable/Script/ScriptParser.ts
@@ -1,7 +1,6 @@
 import type { ScriptData, CodeScriptData, CallScriptData } from '@/application/collections/';
 import { NoEmptyLines } from '@/application/Parser/Executable/Script/Validation/Rules/NoEmptyLines';
 import type { ILanguageSyntax } from '@/application/Parser/Executable/Script/Validation/Syntax/ILanguageSyntax';
-import { CollectionScript } from '@/domain/Executables/Script/CollectionScript';
 import { RecommendationLevel } from '@/domain/Executables/Script/RecommendationLevel';
 import type { ScriptCode } from '@/domain/Executables/Script/Code/ScriptCode';
 import type { ICodeValidator } from '@/application/Parser/Executable/Script/Validation/ICodeValidator';
@@ -11,6 +10,7 @@ import { createScriptCode } from '@/domain/Executables/Script/Code/ScriptCodeFac
 import type { Script } from '@/domain/Executables/Script/Script';
 import { createEnumParser, type EnumParser } from '@/application/Common/Enum';
 import { filterEmptyStrings } from '@/application/Common/Text/FilterEmptyStrings';
+import { createScript, type ScriptFactory } from '@/domain/Executables/Script/ScriptFactory';
 import { parseDocs, type DocsParser } from '../DocumentationParser';
 import { ExecutableType } from '../Validation/ExecutableType';
 import { createExecutableDataValidator, type ExecutableValidator, type ExecutableValidatorFactory } from '../Validation/ExecutableValidator';
@@ -38,6 +38,7 @@ export const parseScript: ScriptParser = (
   validateScript(data, validator);
   try {
     const script = scriptUtilities.createScript({
+      executableId: data.name, // arbitrary ID
       name: data.name,
       code: parseCode(
         data,
@@ -132,14 +133,6 @@ interface ScriptParserUtilities {
   readonly parseDocs: DocsParser;
 }
 
-export type ScriptFactory = (
-  ...parameters: ConstructorParameters<typeof CollectionScript>
-) => Script;
-
-const createScript: ScriptFactory = (...parameters) => {
-  return new CollectionScript(...parameters);
-};
-
 const DefaultUtilities: ScriptParserUtilities = {
   levelParser: createEnumParser(RecommendationLevel),
   createScript,
diff --git a/src/application/Repository/Repository.ts b/src/application/Repository/Repository.ts
index 6232598a..0b2d83d7 100644
--- a/src/application/Repository/Repository.ts
+++ b/src/application/Repository/Repository.ts
@@ -1,17 +1,19 @@
-import type { IEntity } from '@/infrastructure/Entity/IEntity';
+import type { RepositoryEntity } from './RepositoryEntity';
 
-export interface ReadonlyRepository<TKey, TEntity extends IEntity<TKey>> {
+type EntityId = RepositoryEntity['id'];
+
+export interface ReadonlyRepository<TEntity extends RepositoryEntity> {
   readonly length: number;
   getItems(predicate?: (entity: TEntity) => boolean): readonly TEntity[];
-  getById(id: TKey): TEntity;
-  exists(id: TKey): boolean;
+  getById(id: EntityId): TEntity;
+  exists(id: EntityId): boolean;
 }
 
-export interface MutableRepository<TKey, TEntity extends IEntity<TKey>> {
+export interface MutableRepository<TEntity extends RepositoryEntity> {
   addItem(item: TEntity): void;
   addOrUpdateItem(item: TEntity): void;
-  removeItem(id: TKey): void;
+  removeItem(id: EntityId): void;
 }
 
-export interface Repository<TKey, TEntity extends IEntity<TKey>>
-  extends ReadonlyRepository<TKey, TEntity>, MutableRepository<TKey, TEntity> { }
+export interface Repository<TEntity extends RepositoryEntity>
+  extends ReadonlyRepository<TEntity>, MutableRepository<TEntity> { }
diff --git a/src/application/Repository/RepositoryEntity.ts b/src/application/Repository/RepositoryEntity.ts
new file mode 100644
index 00000000..1603cd97
--- /dev/null
+++ b/src/application/Repository/RepositoryEntity.ts
@@ -0,0 +1,6 @@
+/** Aggregate root */
+export type RepositoryEntityId = string;
+
+export interface RepositoryEntity {
+  readonly id: RepositoryEntityId;
+}
diff --git a/src/application/collections/windows.yaml b/src/application/collections/windows.yaml
index b1d7bf12..d582f2f5 100644
--- a/src/application/collections/windows.yaml
+++ b/src/application/collections/windows.yaml
@@ -3207,7 +3207,7 @@ actions:
                                     parameters:
                                         appCapability: bluetoothSync
                     -
-                        category: Disable app access to voice activation
+                        category: Disable app voice activation
                         docs: |- # refactor-with-variable: Same • App Access Caution
                             This category safeguards against unauthorized app activation via voice commands.
 
@@ -15671,7 +15671,7 @@ actions:
                                                         data: '1'
                                                         deleteOnRevert: 'true' # Missing by default since Windows 10 Pro (≥ 22H2) and Windows 11 Pro (≥ 23H2)
                                             -
-                                                category: Minimize CPU usage during scans
+                                                category: Disable intensive CPU usage during Defender scans
                                                 children:
                                                     -
                                                         name: Minimize CPU usage during scans
@@ -15866,7 +15866,7 @@ actions:
                                                 category: Disable scanning archive files
                                                 children:
                                                     -
-                                                        name: Disable scanning archive files
+                                                        name: Disable Defender archive file scanning
                                                         docs:
                                                             - https://admx.help/?Category=Windows_10_2016&Policy=Microsoft.Policies.WindowsDefender::Scan_DisableArchiveScanning
                                                             # Managing with MpPreference module:
diff --git a/src/domain/Application.ts b/src/domain/Application.ts
index 2fc1230d..77e85796 100644
--- a/src/domain/Application.ts
+++ b/src/domain/Application.ts
@@ -1,6 +1,6 @@
 import { OperatingSystem } from './OperatingSystem';
 import type { IApplication } from './IApplication';
-import type { ICategoryCollection } from './ICategoryCollection';
+import type { ICategoryCollection } from './Collection/ICategoryCollection';
 import type { ProjectDetails } from './Project/ProjectDetails';
 
 export class Application implements IApplication {
diff --git a/src/domain/CategoryCollection.ts b/src/domain/Collection/CategoryCollection.ts
similarity index 54%
rename from src/domain/CategoryCollection.ts
rename to src/domain/Collection/CategoryCollection.ts
index 71d8c61e..06527003 100644
--- a/src/domain/CategoryCollection.ts
+++ b/src/domain/Collection/CategoryCollection.ts
@@ -1,11 +1,13 @@
 import { getEnumValues, assertInRange } from '@/application/Common/Enum';
-import { RecommendationLevel } from './Executables/Script/RecommendationLevel';
-import { OperatingSystem } from './OperatingSystem';
-import type { IEntity } from '../infrastructure/Entity/IEntity';
-import type { Category } from './Executables/Category/Category';
-import type { Script } from './Executables/Script/Script';
-import type { IScriptingDefinition } from './IScriptingDefinition';
+import { RecommendationLevel } from '../Executables/Script/RecommendationLevel';
+import { OperatingSystem } from '../OperatingSystem';
+import { validateCategoryCollection } from './Validation/CompositeCategoryCollectionValidator';
+import type { ExecutableId } from '../Executables/Identifiable';
+import type { Category } from '../Executables/Category/Category';
+import type { Script } from '../Executables/Script/Script';
+import type { IScriptingDefinition } from '../IScriptingDefinition';
 import type { ICategoryCollection } from './ICategoryCollection';
+import type { CategoryCollectionValidator } from './Validation/CategoryCollectionValidator';
 
 export class CategoryCollection implements ICategoryCollection {
   public readonly os: OperatingSystem;
@@ -22,22 +24,24 @@ export class CategoryCollection implements ICategoryCollection {
 
   constructor(
     parameters: CategoryCollectionInitParameters,
+    validate: CategoryCollectionValidator = validateCategoryCollection,
   ) {
     this.os = parameters.os;
     this.actions = parameters.actions;
     this.scripting = parameters.scripting;
 
     this.queryable = makeQueryable(this.actions);
-    assertInRange(this.os, OperatingSystem);
-    ensureValid(this.queryable);
-    ensureNoDuplicates(this.queryable.allCategories);
-    ensureNoDuplicates(this.queryable.allScripts);
+    validate({
+      allScripts: this.queryable.allScripts,
+      allCategories: this.queryable.allCategories,
+      operatingSystem: this.os,
+    });
   }
 
-  public getCategory(categoryId: number): Category {
-    const category = this.queryable.allCategories.find((c) => c.id === categoryId);
+  public getCategory(executableId: ExecutableId): Category {
+    const category = this.queryable.allCategories.find((c) => c.executableId === executableId);
     if (!category) {
-      throw new Error(`Missing category with ID: "${categoryId}"`);
+      throw new Error(`Missing category with ID: "${executableId}"`);
     }
     return category;
   }
@@ -48,10 +52,10 @@ export class CategoryCollection implements ICategoryCollection {
     return scripts ?? [];
   }
 
-  public getScript(scriptId: string): Script {
-    const script = this.queryable.allScripts.find((s) => s.id === scriptId);
+  public getScript(executableId: string): Script {
+    const script = this.queryable.allScripts.find((s) => s.executableId === executableId);
     if (!script) {
-      throw new Error(`missing script: ${scriptId}`);
+      throw new Error(`Missing script: ${executableId}`);
     }
     return script;
   }
@@ -65,21 +69,6 @@ export class CategoryCollection implements ICategoryCollection {
   }
 }
 
-function ensureNoDuplicates<TKey>(entities: ReadonlyArray<IEntity<TKey>>) {
-  const isUniqueInArray = (id: TKey, index: number, array: readonly TKey[]) => array
-    .findIndex((otherId) => otherId === id) !== index;
-  const duplicatedIds = entities
-    .map((entity) => entity.id)
-    .filter((id, index, array) => !isUniqueInArray(id, index, array))
-    .filter(isUniqueInArray);
-  if (duplicatedIds.length > 0) {
-    const duplicatedIdsText = duplicatedIds.map((id) => `"${id}"`).join(',');
-    throw new Error(
-      `Duplicate entities are detected with following id(s): ${duplicatedIdsText}`,
-    );
-  }
-}
-
 export interface CategoryCollectionInitParameters {
   readonly os: OperatingSystem;
   readonly actions: ReadonlyArray<Category>;
@@ -92,35 +81,12 @@ interface QueryableCollection {
   readonly scriptsByLevel: Map<RecommendationLevel, readonly Script[]>;
 }
 
-function ensureValid(application: QueryableCollection) {
-  ensureValidCategories(application.allCategories);
-  ensureValidScripts(application.allScripts);
-}
-
-function ensureValidCategories(allCategories: readonly Category[]) {
-  if (!allCategories.length) {
-    throw new Error('must consist of at least one category');
-  }
-}
-
-function ensureValidScripts(allScripts: readonly Script[]) {
-  if (!allScripts.length) {
-    throw new Error('must consist of at least one script');
-  }
-  const missingRecommendationLevels = getEnumValues(RecommendationLevel)
-    .filter((level) => allScripts.every((script) => script.level !== level));
-  if (missingRecommendationLevels.length > 0) {
-    throw new Error('none of the scripts are recommended as'
-      + ` "${missingRecommendationLevels.map((level) => RecommendationLevel[level]).join(', "')}".`);
-  }
-}
-
-function flattenApplication(
+function flattenCategoryHierarchy(
   categories: ReadonlyArray<Category>,
 ): [Category[], Script[]] {
   const [subCategories, subScripts] = (categories || [])
     // Parse children
-    .map((category) => flattenApplication(category.subCategories))
+    .map((category) => flattenCategoryHierarchy(category.subcategories))
     // Flatten results
     .reduce(([previousCategories, previousScripts], [currentCategories, currentScripts]) => {
       return [
@@ -143,7 +109,7 @@ function flattenApplication(
 function makeQueryable(
   actions: ReadonlyArray<Category>,
 ): QueryableCollection {
-  const flattened = flattenApplication(actions);
+  const flattened = flattenCategoryHierarchy(actions);
   return {
     allCategories: flattened[0],
     allScripts: flattened[1],
diff --git a/src/domain/ICategoryCollection.ts b/src/domain/Collection/ICategoryCollection.ts
similarity index 82%
rename from src/domain/ICategoryCollection.ts
rename to src/domain/Collection/ICategoryCollection.ts
index c7b7d799..ac7879fc 100644
--- a/src/domain/ICategoryCollection.ts
+++ b/src/domain/Collection/ICategoryCollection.ts
@@ -3,6 +3,7 @@ import { OperatingSystem } from '@/domain/OperatingSystem';
 import { RecommendationLevel } from '@/domain/Executables/Script/RecommendationLevel';
 import type { Script } from '@/domain/Executables/Script/Script';
 import type { Category } from '@/domain/Executables/Category/Category';
+import type { ExecutableId } from '../Executables/Identifiable';
 
 export interface ICategoryCollection {
   readonly scripting: IScriptingDefinition;
@@ -12,8 +13,8 @@ export interface ICategoryCollection {
   readonly actions: ReadonlyArray<Category>;
 
   getScriptsByLevel(level: RecommendationLevel): ReadonlyArray<Script>;
-  getCategory(categoryId: number): Category;
-  getScript(scriptId: string): Script;
+  getCategory(categoryId: ExecutableId): Category;
+  getScript(scriptId: ExecutableId): Script;
   getAllScripts(): ReadonlyArray<Script>;
   getAllCategories(): ReadonlyArray<Category>;
 }
diff --git a/src/domain/Collection/Validation/CategoryCollectionValidator.ts b/src/domain/Collection/Validation/CategoryCollectionValidator.ts
new file mode 100644
index 00000000..bce3bf82
--- /dev/null
+++ b/src/domain/Collection/Validation/CategoryCollectionValidator.ts
@@ -0,0 +1,15 @@
+import type { Category } from '@/domain/Executables/Category/Category';
+import type { Script } from '@/domain/Executables/Script/Script';
+import type { OperatingSystem } from '@/domain/OperatingSystem';
+
+export interface CategoryCollectionValidationContext {
+  readonly allScripts: readonly Script[];
+  readonly allCategories: readonly Category[];
+  readonly operatingSystem: OperatingSystem;
+}
+
+export interface CategoryCollectionValidator {
+  (
+    context: CategoryCollectionValidationContext,
+  ): void;
+}
diff --git a/src/domain/Collection/Validation/CompositeCategoryCollectionValidator.ts b/src/domain/Collection/Validation/CompositeCategoryCollectionValidator.ts
new file mode 100644
index 00000000..e7876d16
--- /dev/null
+++ b/src/domain/Collection/Validation/CompositeCategoryCollectionValidator.ts
@@ -0,0 +1,33 @@
+import { ensurePresenceOfAtLeastOneScript } from './Rules/EnsurePresenceOfAtLeastOneScript';
+import { ensurePresenceOfAtLeastOneCategory } from './Rules/EnsurePresenceOfAtLeastOneCategory';
+import { ensureUniqueIdsAcrossExecutables } from './Rules/EnsureUniqueIdsAcrossExecutables';
+import { ensureKnownOperatingSystem } from './Rules/EnsureKnownOperatingSystem';
+import type { CategoryCollectionValidationContext, CategoryCollectionValidator } from './CategoryCollectionValidator';
+
+export type CompositeCategoryCollectionValidator = CategoryCollectionValidator & {
+  (
+    ...args: [
+      ...Parameters<CategoryCollectionValidator>,
+      (readonly CategoryCollectionValidator[])?,
+    ]
+  ): void;
+};
+
+export const validateCategoryCollection: CompositeCategoryCollectionValidator = (
+  context: CategoryCollectionValidationContext,
+  validators: readonly CategoryCollectionValidator[] = DefaultValidators,
+) => {
+  if (!validators.length) {
+    throw new Error('No validators provided.');
+  }
+  for (const validate of validators) {
+    validate(context);
+  }
+};
+
+const DefaultValidators: readonly CategoryCollectionValidator[] = [
+  ensureKnownOperatingSystem,
+  ensurePresenceOfAtLeastOneScript,
+  ensurePresenceOfAtLeastOneCategory,
+  ensureUniqueIdsAcrossExecutables,
+];
diff --git a/src/domain/Collection/Validation/Rules/EnsureKnownOperatingSystem.ts b/src/domain/Collection/Validation/Rules/EnsureKnownOperatingSystem.ts
new file mode 100644
index 00000000..b3af7f96
--- /dev/null
+++ b/src/domain/Collection/Validation/Rules/EnsureKnownOperatingSystem.ts
@@ -0,0 +1,9 @@
+import { assertInRange } from '@/application/Common/Enum';
+import { OperatingSystem } from '@/domain/OperatingSystem';
+import type { CategoryCollectionValidator } from '../CategoryCollectionValidator';
+
+export const ensureKnownOperatingSystem: CategoryCollectionValidator = (
+  context,
+) => {
+  assertInRange(context.operatingSystem, OperatingSystem);
+};
diff --git a/src/domain/Collection/Validation/Rules/EnsurePresenceOfAllRecommendationLevels.ts b/src/domain/Collection/Validation/Rules/EnsurePresenceOfAllRecommendationLevels.ts
new file mode 100644
index 00000000..8c2c6114
--- /dev/null
+++ b/src/domain/Collection/Validation/Rules/EnsurePresenceOfAllRecommendationLevels.ts
@@ -0,0 +1,35 @@
+import { getEnumValues } from '@/application/Common/Enum';
+import { RecommendationLevel } from '@/domain/Executables/Script/RecommendationLevel';
+import type { Script } from '@/domain/Executables/Script/Script';
+import type { CategoryCollectionValidator } from '../CategoryCollectionValidator';
+
+export const ensurePresenceOfAllRecommendationLevels: CategoryCollectionValidator = (
+  context,
+) => {
+  const unrepresentedRecommendationLevels = getUnrepresentedRecommendationLevels(
+    context.allScripts,
+  );
+  if (unrepresentedRecommendationLevels.length === 0) {
+    return;
+  }
+  const formattedRecommendationLevels = unrepresentedRecommendationLevels
+    .map((level) => getDisplayName(level))
+    .join(', ');
+  throw new Error(`Missing recommendation levels: ${formattedRecommendationLevels}.`);
+};
+
+function getUnrepresentedRecommendationLevels(
+  scripts: readonly Script[],
+): (RecommendationLevel | undefined)[] {
+  const expectedLevels = [
+    undefined,
+    ...getEnumValues(RecommendationLevel),
+  ];
+  return expectedLevels.filter(
+    (level) => scripts.every((script) => script.level !== level),
+  );
+}
+
+function getDisplayName(level: RecommendationLevel | undefined): string {
+  return level === undefined ? 'None' : RecommendationLevel[level];
+}
diff --git a/src/domain/Collection/Validation/Rules/EnsurePresenceOfAtLeastOneCategory.ts b/src/domain/Collection/Validation/Rules/EnsurePresenceOfAtLeastOneCategory.ts
new file mode 100644
index 00000000..7d3e7655
--- /dev/null
+++ b/src/domain/Collection/Validation/Rules/EnsurePresenceOfAtLeastOneCategory.ts
@@ -0,0 +1,9 @@
+import type { CategoryCollectionValidator } from '../CategoryCollectionValidator';
+
+export const ensurePresenceOfAtLeastOneCategory: CategoryCollectionValidator = (
+  context,
+) => {
+  if (!context.allCategories.length) {
+    throw new Error('Collection must have at least one category');
+  }
+};
diff --git a/src/domain/Collection/Validation/Rules/EnsurePresenceOfAtLeastOneScript.ts b/src/domain/Collection/Validation/Rules/EnsurePresenceOfAtLeastOneScript.ts
new file mode 100644
index 00000000..333e97cb
--- /dev/null
+++ b/src/domain/Collection/Validation/Rules/EnsurePresenceOfAtLeastOneScript.ts
@@ -0,0 +1,9 @@
+import type { CategoryCollectionValidator } from '../CategoryCollectionValidator';
+
+export const ensurePresenceOfAtLeastOneScript: CategoryCollectionValidator = (
+  context,
+) => {
+  if (!context.allScripts.length) {
+    throw new Error('Collection must have at least one script');
+  }
+};
diff --git a/src/domain/Collection/Validation/Rules/EnsureUniqueIdsAcrossExecutables.ts b/src/domain/Collection/Validation/Rules/EnsureUniqueIdsAcrossExecutables.ts
new file mode 100644
index 00000000..34c09180
--- /dev/null
+++ b/src/domain/Collection/Validation/Rules/EnsureUniqueIdsAcrossExecutables.ts
@@ -0,0 +1,43 @@
+import type { Identifiable } from '@/domain/Executables/Identifiable';
+import type { CategoryCollectionValidator } from '../CategoryCollectionValidator';
+
+export const ensureUniqueIdsAcrossExecutables: CategoryCollectionValidator = (
+  context,
+) => {
+  const allExecutables: readonly Identifiable[] = [
+    ...context.allCategories,
+    ...context.allScripts,
+  ];
+  ensureNoDuplicateIds(allExecutables);
+};
+
+function ensureNoDuplicateIds(
+  executables: readonly Identifiable[],
+) {
+  const duplicateExecutables = getExecutablesWithDuplicateIds(executables);
+  if (duplicateExecutables.length === 0) {
+    return;
+  }
+  const formattedDuplicateIds = duplicateExecutables.map(
+    (executable) => `"${executable.executableId}"`,
+  ).join(', ');
+  throw new Error(`Duplicate executable IDs found: ${formattedDuplicateIds}`);
+}
+
+function getExecutablesWithDuplicateIds(
+  executables: readonly Identifiable[],
+): Identifiable[] {
+  return executables
+    .filter(
+      (executable, index, array) => {
+        const otherIndex = array.findIndex(
+          (otherExecutable) => haveIdenticalIds(executable, otherExecutable),
+        );
+        return otherIndex !== index;
+      },
+    );
+}
+
+function haveIdenticalIds(first: Identifiable, second: Identifiable): boolean {
+  return first.executableId === second.executableId;
+}
diff --git a/src/domain/Executables/Category/Category.ts b/src/domain/Executables/Category/Category.ts
index ff0bd93f..a080a331 100644
--- a/src/domain/Executables/Category/Category.ts
+++ b/src/domain/Executables/Category/Category.ts
@@ -1,10 +1,9 @@
 import type { Script } from '../Script/Script';
 import type { Executable } from '../Executable';
 
-export interface Category extends Executable<number> {
-  readonly id: number;
+export interface Category extends Executable {
   readonly name: string;
-  readonly subCategories: ReadonlyArray<Category>;
+  readonly subcategories: ReadonlyArray<Category>;
   readonly scripts: ReadonlyArray<Script>;
   includes(script: Script): boolean;
   getAllScriptsRecursively(): ReadonlyArray<Script>;
diff --git a/src/domain/Executables/Category/CollectionCategory.ts b/src/domain/Executables/Category/CategoryFactory.ts
similarity index 57%
rename from src/domain/Executables/Category/CollectionCategory.ts
rename to src/domain/Executables/Category/CategoryFactory.ts
index 5d51d0a1..7afba3fb 100644
--- a/src/domain/Executables/Category/CollectionCategory.ts
+++ b/src/domain/Executables/Category/CategoryFactory.ts
@@ -1,29 +1,51 @@
-import { BaseEntity } from '@/infrastructure/Entity/BaseEntity';
-import type { Category } from './Category';
-import type { Script } from '../Script/Script';
+import type { Category } from '@/domain/Executables/Category/Category';
+import type { Script } from '@/domain/Executables/Script/Script';
+import type { ExecutableId } from '../Identifiable';
 
-export class CollectionCategory extends BaseEntity<number> implements Category {
-  private allSubScripts?: ReadonlyArray<Script> = undefined;
+export type CategoryFactory = (
+  parameters: CategoryInitParameters,
+) => Category;
+
+export interface CategoryInitParameters {
+  readonly executableId: ExecutableId;
+  readonly name: string;
+  readonly docs: ReadonlyArray<string>;
+  readonly subcategories: ReadonlyArray<Category>;
+  readonly scripts: ReadonlyArray<Script>;
+}
+
+export const createCategory: CategoryFactory = (
+  parameters,
+) => {
+  return new CollectionCategory(parameters);
+};
+
+class CollectionCategory implements Category {
+  public readonly executableId: ExecutableId;
 
   public readonly name: string;
 
   public readonly docs: ReadonlyArray<string>;
 
-  public readonly subCategories: ReadonlyArray<Category>;
+  public readonly subcategories: ReadonlyArray<Category>;
 
   public readonly scripts: ReadonlyArray<Script>;
 
+  private allSubScripts?: ReadonlyArray<Script> = undefined;
+
   constructor(parameters: CategoryInitParameters) {
-    super(parameters.id);
     validateParameters(parameters);
+    this.executableId = parameters.executableId;
     this.name = parameters.name;
     this.docs = parameters.docs;
-    this.subCategories = parameters.subcategories;
+    this.subcategories = parameters.subcategories;
     this.scripts = parameters.scripts;
   }
 
   public includes(script: Script): boolean {
-    return this.getAllScriptsRecursively().some((childScript) => childScript.id === script.id);
+    return this
+      .getAllScriptsRecursively()
+      .some((childScript) => childScript.executableId === script.executableId);
   }
 
   public getAllScriptsRecursively(): readonly Script[] {
@@ -34,22 +56,17 @@ export class CollectionCategory extends BaseEntity<number> implements Category {
   }
 }
 
-export interface CategoryInitParameters {
-  readonly id: number;
-  readonly name: string;
-  readonly docs: ReadonlyArray<string>;
-  readonly subcategories: ReadonlyArray<Category>;
-  readonly scripts: ReadonlyArray<Script>;
-}
-
 function parseScriptsRecursively(category: Category): ReadonlyArray<Script> {
   return [
     ...category.scripts,
-    ...category.subCategories.flatMap((c) => c.getAllScriptsRecursively()),
+    ...category.subcategories.flatMap((c) => c.getAllScriptsRecursively()),
   ];
 }
 
 function validateParameters(parameters: CategoryInitParameters) {
+  if (!parameters.executableId) {
+    throw new Error('missing ID');
+  }
   if (!parameters.name) {
     throw new Error('missing name');
   }
diff --git a/src/domain/Executables/Executable.ts b/src/domain/Executables/Executable.ts
index 39e6d908..c82ba28f 100644
--- a/src/domain/Executables/Executable.ts
+++ b/src/domain/Executables/Executable.ts
@@ -1,6 +1,6 @@
-import type { IEntity } from '@/infrastructure/Entity/IEntity';
 import type { Documentable } from './Documentable';
+import type { Identifiable } from './Identifiable';
 
-export interface Executable<TExecutableKey>
-  extends Documentable, IEntity<TExecutableKey> {
+export interface Executable
+  extends Documentable, Identifiable {
 }
diff --git a/src/domain/Executables/Identifiable.ts b/src/domain/Executables/Identifiable.ts
new file mode 100644
index 00000000..33a1053e
--- /dev/null
+++ b/src/domain/Executables/Identifiable.ts
@@ -0,0 +1,5 @@
+export type ExecutableId = string;
+
+export interface Identifiable {
+  readonly executableId: ExecutableId;
+}
diff --git a/src/domain/Executables/Script/Script.ts b/src/domain/Executables/Script/Script.ts
index 705264d8..0c17f8f9 100644
--- a/src/domain/Executables/Script/Script.ts
+++ b/src/domain/Executables/Script/Script.ts
@@ -3,7 +3,7 @@ import type { Executable } from '../Executable';
 import type { Documentable } from '../Documentable';
 import type { ScriptCode } from './Code/ScriptCode';
 
-export interface Script extends Executable<string>, Documentable {
+export interface Script extends Executable, Documentable {
   readonly name: string;
   readonly level?: RecommendationLevel;
   readonly code: ScriptCode;
diff --git a/src/domain/Executables/Script/CollectionScript.ts b/src/domain/Executables/Script/ScriptFactory.ts
similarity index 73%
rename from src/domain/Executables/Script/CollectionScript.ts
rename to src/domain/Executables/Script/ScriptFactory.ts
index dd9f34fc..244cc9ea 100644
--- a/src/domain/Executables/Script/CollectionScript.ts
+++ b/src/domain/Executables/Script/ScriptFactory.ts
@@ -1,9 +1,26 @@
-import { BaseEntity } from '@/infrastructure/Entity/BaseEntity';
 import { RecommendationLevel } from './RecommendationLevel';
-import type { Script } from './Script';
 import type { ScriptCode } from './Code/ScriptCode';
+import type { Script } from './Script';
+
+export interface ScriptInitParameters {
+  readonly executableId: string;
+  readonly name: string;
+  readonly code: ScriptCode;
+  readonly docs: ReadonlyArray<string>;
+  readonly level?: RecommendationLevel;
+}
+
+export type ScriptFactory = (
+  parameters: ScriptInitParameters,
+) => Script;
+
+export const createScript: ScriptFactory = (parameters) => {
+  return new CollectionScript(parameters);
+};
+
+class CollectionScript implements Script {
+  public readonly executableId: string;
 
-export class CollectionScript extends BaseEntity<string> implements Script {
   public readonly name: string;
 
   public readonly code: ScriptCode;
@@ -13,7 +30,7 @@ export class CollectionScript extends BaseEntity<string> implements Script {
   public readonly level?: RecommendationLevel;
 
   constructor(parameters: ScriptInitParameters) {
-    super(parameters.name);
+    this.executableId = parameters.executableId;
     this.name = parameters.name;
     this.code = parameters.code;
     this.docs = parameters.docs;
@@ -26,13 +43,6 @@ export class CollectionScript extends BaseEntity<string> implements Script {
   }
 }
 
-export interface ScriptInitParameters {
-  readonly name: string;
-  readonly code: ScriptCode;
-  readonly docs: ReadonlyArray<string>;
-  readonly level?: RecommendationLevel;
-}
-
 function validateLevel(level?: RecommendationLevel) {
   if (level !== undefined && !(level in RecommendationLevel)) {
     throw new Error(`invalid level: ${level}`);
diff --git a/src/domain/IApplication.ts b/src/domain/IApplication.ts
index 0cdf6503..946e1128 100644
--- a/src/domain/IApplication.ts
+++ b/src/domain/IApplication.ts
@@ -1,4 +1,4 @@
-import type { ICategoryCollection } from './ICategoryCollection';
+import type { ICategoryCollection } from './Collection/ICategoryCollection';
 import type { ProjectDetails } from './Project/ProjectDetails';
 import type { OperatingSystem } from './OperatingSystem';
 
diff --git a/src/infrastructure/Entity/BaseEntity.ts b/src/infrastructure/Entity/BaseEntity.ts
deleted file mode 100644
index caa212aa..00000000
--- a/src/infrastructure/Entity/BaseEntity.ts
+++ /dev/null
@@ -1,14 +0,0 @@
-import { isNumber } from '@/TypeHelpers';
-import type { IEntity } from './IEntity';
-
-export abstract class BaseEntity<TId> implements IEntity<TId> {
-  protected constructor(public id: TId) {
-    if (!isNumber(id) && !id) {
-      throw new Error('Id cannot be null or empty');
-    }
-  }
-
-  public equals(otherId: TId): boolean {
-    return this.id === otherId;
-  }
-}
diff --git a/src/infrastructure/Entity/IEntity.ts b/src/infrastructure/Entity/IEntity.ts
deleted file mode 100644
index def877b1..00000000
--- a/src/infrastructure/Entity/IEntity.ts
+++ /dev/null
@@ -1,5 +0,0 @@
-/** Aggregate root */
-export interface IEntity<TId> {
-  id: TId;
-  equals(other: TId): boolean;
-}
diff --git a/src/infrastructure/Repository/InMemoryRepository.ts b/src/infrastructure/Repository/InMemoryRepository.ts
index b0051673..e1d19467 100644
--- a/src/infrastructure/Repository/InMemoryRepository.ts
+++ b/src/infrastructure/Repository/InMemoryRepository.ts
@@ -1,12 +1,15 @@
 import type { Repository } from '../../application/Repository/Repository';
-import type { IEntity } from '../Entity/IEntity';
+import type { RepositoryEntity } from '../../application/Repository/RepositoryEntity';
 
-export class InMemoryRepository<TKey, TEntity extends IEntity<TKey>>
-implements Repository<TKey, TEntity> {
+export class InMemoryRepository<TEntity extends RepositoryEntity>
+implements Repository<TEntity> {
   private readonly items: TEntity[];
 
-  constructor(items?: TEntity[]) {
-    this.items = items ?? new Array<TEntity>();
+  constructor(items?: readonly TEntity[]) {
+    this.items = new Array<TEntity>();
+    if (items) {
+      this.items.push(...items);
+    }
   }
 
   public get length(): number {
@@ -17,7 +20,7 @@ implements Repository<TKey, TEntity> {
     return predicate ? this.items.filter(predicate) : this.items;
   }
 
-  public getById(id: TKey): TEntity {
+  public getById(id: string): TEntity {
     const items = this.getItems((entity) => entity.id === id);
     if (!items.length) {
       throw new Error(`missing item: ${id}`);
@@ -39,7 +42,7 @@ implements Repository<TKey, TEntity> {
     this.items.push(item);
   }
 
-  public removeItem(id: TKey): void {
+  public removeItem(id: string): void {
     const index = this.items.findIndex((item) => item.id === id);
     if (index === -1) {
       throw new Error(`Cannot remove (id: ${id}) as it does not exist`);
@@ -47,7 +50,7 @@ implements Repository<TKey, TEntity> {
     this.items.splice(index, 1);
   }
 
-  public exists(id: TKey): boolean {
+  public exists(id: string): boolean {
     const index = this.items.findIndex((item) => item.id === id);
     return index !== -1;
   }
diff --git a/src/presentation/components/Scripts/Menu/Recommendation/RecommendationStatusHandler.ts b/src/presentation/components/Scripts/Menu/Recommendation/RecommendationStatusHandler.ts
index abed6184..5eaff647 100644
--- a/src/presentation/components/Scripts/Menu/Recommendation/RecommendationStatusHandler.ts
+++ b/src/presentation/components/Scripts/Menu/Recommendation/RecommendationStatusHandler.ts
@@ -1,7 +1,7 @@
 import type { Script } from '@/domain/Executables/Script/Script';
 import { RecommendationLevel } from '@/domain/Executables/Script/RecommendationLevel';
 import { scrambledEqual } from '@/application/Common/Array';
-import type { ICategoryCollection } from '@/domain/ICategoryCollection';
+import type { ICategoryCollection } from '@/domain/Collection/ICategoryCollection';
 import type { ReadonlyScriptSelection, ScriptSelection } from '@/application/Context/State/Selection/Script/ScriptSelection';
 import type { SelectedScript } from '@/application/Context/State/Selection/Script/SelectedScript';
 import { RecommendationStatusType } from './RecommendationStatusType';
@@ -99,6 +99,6 @@ function areAllSelected(
   if (expectedScripts.length < selectedScriptIds.length) {
     return false;
   }
-  const expectedScriptIds = expectedScripts.map((script) => script.id);
+  const expectedScriptIds = expectedScripts.map((script) => script.executableId);
   return scrambledEqual(selectedScriptIds, expectedScriptIds);
 }
diff --git a/src/presentation/components/Scripts/Menu/Recommendation/TheRecommendationSelector.vue b/src/presentation/components/Scripts/Menu/Recommendation/TheRecommendationSelector.vue
index f3da4814..bf0db7a5 100644
--- a/src/presentation/components/Scripts/Menu/Recommendation/TheRecommendationSelector.vue
+++ b/src/presentation/components/Scripts/Menu/Recommendation/TheRecommendationSelector.vue
@@ -90,7 +90,7 @@ import {
 } from 'vue';
 import { injectKey } from '@/presentation/injectionSymbols';
 import TooltipWrapper from '@/presentation/components/Shared/TooltipWrapper.vue';
-import type { ICategoryCollection } from '@/domain/ICategoryCollection';
+import type { ICategoryCollection } from '@/domain/Collection/ICategoryCollection';
 import MenuOptionList from '../MenuOptionList.vue';
 import MenuOptionListItem from '../MenuOptionListItem.vue';
 import { setCurrentRecommendationStatus, getCurrentRecommendationStatus } from './RecommendationStatusHandler';
@@ -142,3 +142,4 @@ export default defineComponent({
   },
 });
 </script>
+@/domain/Collection/ICategoryCollection
diff --git a/src/presentation/components/Scripts/View/Cards/CardList.vue b/src/presentation/components/Scripts/View/Cards/CardList.vue
index dd831327..f054265e 100644
--- a/src/presentation/components/Scripts/View/Cards/CardList.vue
+++ b/src/presentation/components/Scripts/View/Cards/CardList.vue
@@ -44,6 +44,7 @@ import {
 } from 'vue';
 import { injectKey } from '@/presentation/injectionSymbols';
 import SizeObserver from '@/presentation/components/Shared/SizeObserver.vue';
+import type { ExecutableId } from '@/domain/Executables/Identifiable';
 import { hasDirective } from './NonCollapsingDirective';
 import CardListItem from './CardListItem.vue';
 
@@ -58,12 +59,12 @@ export default defineComponent({
 
     const width = ref<number | undefined>();
 
-    const categoryIds = computed<readonly number[]>(
-      () => currentState.value.collection.actions.map((category) => category.id),
+    const categoryIds = computed<readonly ExecutableId[]>(
+      () => currentState.value.collection.actions.map((category) => category.executableId),
     );
-    const activeCategoryId = ref<number | undefined>(undefined);
+    const activeCategoryId = ref<ExecutableId | undefined>(undefined);
 
-    function onSelected(categoryId: number, isExpanded: boolean) {
+    function onSelected(categoryId: ExecutableId, isExpanded: boolean) {
       activeCategoryId.value = isExpanded ? categoryId : undefined;
     }
 
diff --git a/src/presentation/components/Scripts/View/Cards/CardListItem.vue b/src/presentation/components/Scripts/View/Cards/CardListItem.vue
index 454167f0..74c175f3 100644
--- a/src/presentation/components/Scripts/View/Cards/CardListItem.vue
+++ b/src/presentation/components/Scripts/View/Cards/CardListItem.vue
@@ -56,12 +56,14 @@
 <script lang="ts">
 import {
   defineComponent, computed, shallowRef,
+  type PropType,
 } from 'vue';
 import AppIcon from '@/presentation/components/Shared/Icon/AppIcon.vue';
 import FlatButton from '@/presentation/components/Shared/FlatButton.vue';
 import { injectKey } from '@/presentation/injectionSymbols';
 import ScriptsTree from '@/presentation/components/Scripts/View/Tree/ScriptsTree.vue';
 import { sleep } from '@/infrastructure/Threading/AsyncSleep';
+import type { ExecutableId } from '@/domain/Executables/Identifiable';
 import CardSelectionIndicator from './CardSelectionIndicator.vue';
 import CardExpandTransition from './CardExpandTransition.vue';
 import CardExpansionArrow from './CardExpansionArrow.vue';
@@ -77,11 +79,11 @@ export default defineComponent({
   },
   props: {
     categoryId: {
-      type: Number,
+      type: String as PropType<ExecutableId>,
       required: true,
     },
     activeCategoryId: {
-      type: Number,
+      type: String as PropType<ExecutableId>,
       default: undefined,
     },
   },
diff --git a/src/presentation/components/Scripts/View/Cards/CardSelectionIndicator.vue b/src/presentation/components/Scripts/View/Cards/CardSelectionIndicator.vue
index 50295ca2..9452ab99 100644
--- a/src/presentation/components/Scripts/View/Cards/CardSelectionIndicator.vue
+++ b/src/presentation/components/Scripts/View/Cards/CardSelectionIndicator.vue
@@ -12,11 +12,12 @@
 </template>
 
 <script lang="ts">
-import { defineComponent, computed } from 'vue';
+import { defineComponent, computed, type PropType } from 'vue';
 import AppIcon from '@/presentation/components/Shared/Icon/AppIcon.vue';
 import { injectKey } from '@/presentation/injectionSymbols';
 import type { Category } from '@/domain/Executables/Category/Category';
-import type { ICategoryCollection } from '@/domain/ICategoryCollection';
+import type { ICategoryCollection } from '@/domain/Collection/ICategoryCollection';
+import type { ExecutableId } from '@/domain/Executables/Identifiable';
 
 export default defineComponent({
   components: {
@@ -24,7 +25,7 @@ export default defineComponent({
   },
   props: {
     categoryId: {
-      type: Number,
+      type: String as PropType<ExecutableId>,
       required: true,
     },
   },
@@ -60,3 +61,4 @@ export default defineComponent({
   font-size: $font-size-absolute-normal;
 }
 </style>
+@/domain/Collection/ICategoryCollection
diff --git a/src/presentation/components/Scripts/View/Tree/NodeContent/NodeMetadata.ts b/src/presentation/components/Scripts/View/Tree/NodeContent/NodeMetadata.ts
index 69e1a55a..a1f8c915 100644
--- a/src/presentation/components/Scripts/View/Tree/NodeContent/NodeMetadata.ts
+++ b/src/presentation/components/Scripts/View/Tree/NodeContent/NodeMetadata.ts
@@ -1,10 +1,12 @@
+import type { ExecutableId } from '@/domain/Executables/Identifiable';
+
 export enum NodeType {
   Script,
   Category,
 }
 
 export interface NodeMetadata {
-  readonly id: string;
+  readonly id: ExecutableId;
   readonly text: string;
   readonly isReversible: boolean;
   readonly docs: ReadonlyArray<string>;
diff --git a/src/presentation/components/Scripts/View/Tree/NodeContent/RevertToggle.vue b/src/presentation/components/Scripts/View/Tree/NodeContent/RevertToggle.vue
index a4f66b1a..36915ea3 100644
--- a/src/presentation/components/Scripts/View/Tree/NodeContent/RevertToggle.vue
+++ b/src/presentation/components/Scripts/View/Tree/NodeContent/RevertToggle.vue
@@ -12,7 +12,7 @@ import {
 } from 'vue';
 import { injectKey } from '@/presentation/injectionSymbols';
 import type { NodeMetadata } from '@/presentation/components/Scripts/View/Tree/NodeContent/NodeMetadata';
-import type { ICategoryCollection } from '@/domain/ICategoryCollection';
+import type { ICategoryCollection } from '@/domain/Collection/ICategoryCollection';
 import { getReverter } from './Reverter/ReverterFactory';
 import ToggleSwitch from './ToggleSwitch.vue';
 import type { Reverter } from './Reverter/Reverter';
@@ -64,3 +64,4 @@ export default defineComponent({
   },
 });
 </script>
+@/domain/Collection/ICategoryCollection
diff --git a/src/presentation/components/Scripts/View/Tree/NodeContent/Reverter/CategoryReverter.ts b/src/presentation/components/Scripts/View/Tree/NodeContent/Reverter/CategoryReverter.ts
index 8175b400..e13affa4 100644
--- a/src/presentation/components/Scripts/View/Tree/NodeContent/Reverter/CategoryReverter.ts
+++ b/src/presentation/components/Scripts/View/Tree/NodeContent/Reverter/CategoryReverter.ts
@@ -1,17 +1,19 @@
 import type { UserSelection } from '@/application/Context/State/Selection/UserSelection';
-import type { ICategoryCollection } from '@/domain/ICategoryCollection';
+import type { ICategoryCollection } from '@/domain/Collection/ICategoryCollection';
 import type { SelectedScript } from '@/application/Context/State/Selection/Script/SelectedScript';
-import { getCategoryId } from '../../TreeViewAdapter/CategoryNodeMetadataConverter';
+import type { ExecutableId } from '@/domain/Executables/Identifiable';
+import { createExecutableIdFromNodeId } from '../../TreeViewAdapter/CategoryNodeMetadataConverter';
 import { ScriptReverter } from './ScriptReverter';
 import type { Reverter } from './Reverter';
+import type { TreeNodeId } from '../../TreeView/Node/TreeNode';
 
 export class CategoryReverter implements Reverter {
-  private readonly categoryId: number;
+  private readonly categoryId: ExecutableId;
 
   private readonly scriptReverters: ReadonlyArray<ScriptReverter>;
 
-  constructor(nodeId: string, collection: ICategoryCollection) {
-    this.categoryId = getCategoryId(nodeId);
+  constructor(nodeId: TreeNodeId, collection: ICategoryCollection) {
+    this.categoryId = createExecutableIdFromNodeId(nodeId);
     this.scriptReverters = createScriptReverters(this.categoryId, collection);
   }
 
@@ -37,12 +39,12 @@ export class CategoryReverter implements Reverter {
 }
 
 function createScriptReverters(
-  categoryId: number,
+  categoryId: ExecutableId,
   collection: ICategoryCollection,
 ): ScriptReverter[] {
   const category = collection.getCategory(categoryId);
   const scripts = category
     .getAllScriptsRecursively()
     .filter((script) => script.canRevert());
-  return scripts.map((script) => new ScriptReverter(script.id));
+  return scripts.map((script) => new ScriptReverter(script.executableId));
 }
diff --git a/src/presentation/components/Scripts/View/Tree/NodeContent/Reverter/ReverterFactory.ts b/src/presentation/components/Scripts/View/Tree/NodeContent/Reverter/ReverterFactory.ts
index 1ea96de0..6c6e2bf0 100644
--- a/src/presentation/components/Scripts/View/Tree/NodeContent/Reverter/ReverterFactory.ts
+++ b/src/presentation/components/Scripts/View/Tree/NodeContent/Reverter/ReverterFactory.ts
@@ -1,10 +1,13 @@
-import type { ICategoryCollection } from '@/domain/ICategoryCollection';
+import type { ICategoryCollection } from '@/domain/Collection/ICategoryCollection';
 import { type NodeMetadata, NodeType } from '../NodeMetadata';
 import { ScriptReverter } from './ScriptReverter';
 import { CategoryReverter } from './CategoryReverter';
 import type { Reverter } from './Reverter';
 
-export function getReverter(node: NodeMetadata, collection: ICategoryCollection): Reverter {
+export function getReverter(
+  node: NodeMetadata,
+  collection: ICategoryCollection,
+): Reverter {
   switch (node.type) {
     case NodeType.Category:
       return new CategoryReverter(node.id, collection);
diff --git a/src/presentation/components/Scripts/View/Tree/NodeContent/Reverter/ScriptReverter.ts b/src/presentation/components/Scripts/View/Tree/NodeContent/Reverter/ScriptReverter.ts
index ae4a5efd..d6f619df 100644
--- a/src/presentation/components/Scripts/View/Tree/NodeContent/Reverter/ScriptReverter.ts
+++ b/src/presentation/components/Scripts/View/Tree/NodeContent/Reverter/ScriptReverter.ts
@@ -1,13 +1,13 @@
 import type { UserSelection } from '@/application/Context/State/Selection/UserSelection';
 import type { SelectedScript } from '@/application/Context/State/Selection/Script/SelectedScript';
-import { getScriptId } from '../../TreeViewAdapter/CategoryNodeMetadataConverter';
+import { createExecutableIdFromNodeId } from '../../TreeViewAdapter/CategoryNodeMetadataConverter';
 import type { Reverter } from './Reverter';
 
 export class ScriptReverter implements Reverter {
   private readonly scriptId: string;
 
   constructor(nodeId: string) {
-    this.scriptId = getScriptId(nodeId);
+    this.scriptId = createExecutableIdFromNodeId(nodeId);
   }
 
   public getState(selectedScripts: ReadonlyArray<SelectedScript>): boolean {
diff --git a/src/presentation/components/Scripts/View/Tree/ScriptsTree.vue b/src/presentation/components/Scripts/View/Tree/ScriptsTree.vue
index daf58d76..c082c829 100644
--- a/src/presentation/components/Scripts/View/Tree/ScriptsTree.vue
+++ b/src/presentation/components/Scripts/View/Tree/ScriptsTree.vue
@@ -24,8 +24,9 @@
 </template>
 
 <script lang="ts">
-import { defineComponent, toRef } from 'vue';
+import { defineComponent, toRef, type PropType } from 'vue';
 import { injectKey } from '@/presentation/injectionSymbols';
+import type { ExecutableId } from '@/domain/Executables/Identifiable';
 import TreeView from './TreeView/TreeView.vue';
 import NodeContent from './NodeContent/NodeContent.vue';
 import { useTreeViewFilterEvent } from './TreeViewAdapter/UseTreeViewFilterEvent';
@@ -41,7 +42,7 @@ export default defineComponent({
   },
   props: {
     categoryId: {
-      type: [Number],
+      type: String as PropType<ExecutableId>,
       default: undefined,
     },
     hasTopPadding: {
diff --git a/src/presentation/components/Scripts/View/Tree/TreeView/Bindings/TreeInputNodeData.ts b/src/presentation/components/Scripts/View/Tree/TreeView/Bindings/TreeInputNodeData.ts
index 7964bfd6..09868d08 100644
--- a/src/presentation/components/Scripts/View/Tree/TreeView/Bindings/TreeInputNodeData.ts
+++ b/src/presentation/components/Scripts/View/Tree/TreeView/Bindings/TreeInputNodeData.ts
@@ -1,5 +1,7 @@
+export type TreeInputNodeDataId = string;
+
 export interface TreeInputNodeData {
-  readonly id: string;
+  readonly id: TreeInputNodeDataId;
   readonly children?: readonly TreeInputNodeData[];
   readonly parent?: TreeInputNodeData | null;
   readonly data?: object;
diff --git a/src/presentation/components/Scripts/View/Tree/TreeView/Node/HierarchicalTreeNode.vue b/src/presentation/components/Scripts/View/Tree/TreeView/Node/HierarchicalTreeNode.vue
index 9f8cd3ec..5d04c734 100644
--- a/src/presentation/components/Scripts/View/Tree/TreeView/Node/HierarchicalTreeNode.vue
+++ b/src/presentation/components/Scripts/View/Tree/TreeView/Node/HierarchicalTreeNode.vue
@@ -56,7 +56,7 @@ import { useNodeState } from './UseNodeState';
 import LeafTreeNode from './LeafTreeNode.vue';
 import InteractableNode from './InteractableNode.vue';
 import type { TreeRoot } from '../TreeRoot/TreeRoot';
-import type { TreeNode } from './TreeNode';
+import type { TreeNode, TreeNodeId } from './TreeNode';
 import type { NodeRenderingStrategy } from '../Rendering/Scheduling/NodeRenderingStrategy';
 import type { PropType } from 'vue';
 
@@ -69,7 +69,7 @@ export default defineComponent({
   },
   props: {
     nodeId: {
-      type: String,
+      type: String as PropType<TreeNodeId>,
       required: true,
     },
     treeRoot: {
diff --git a/src/presentation/components/Scripts/View/Tree/TreeView/Node/InteractableNode.vue b/src/presentation/components/Scripts/View/Tree/TreeView/Node/InteractableNode.vue
index 7eee7e57..94b052a2 100644
--- a/src/presentation/components/Scripts/View/Tree/TreeView/Node/InteractableNode.vue
+++ b/src/presentation/components/Scripts/View/Tree/TreeView/Node/InteractableNode.vue
@@ -18,13 +18,13 @@ import { useCurrentTreeNodes } from '../UseCurrentTreeNodes';
 import { useNodeState } from './UseNodeState';
 import { useKeyboardInteractionState } from './UseKeyboardInteractionState';
 import type { TreeRoot } from '../TreeRoot/TreeRoot';
-import type { TreeNode } from './TreeNode';
+import type { TreeNode, TreeNodeId } from './TreeNode';
 import type { PropType } from 'vue';
 
 export default defineComponent({
   props: {
     nodeId: {
-      type: String,
+      type: String as PropType<TreeNodeId>,
       required: true,
     },
     treeRoot: {
diff --git a/src/presentation/components/Scripts/View/Tree/TreeView/Node/LeafTreeNode.vue b/src/presentation/components/Scripts/View/Tree/TreeView/Node/LeafTreeNode.vue
index 7772081e..db17945b 100644
--- a/src/presentation/components/Scripts/View/Tree/TreeView/Node/LeafTreeNode.vue
+++ b/src/presentation/components/Scripts/View/Tree/TreeView/Node/LeafTreeNode.vue
@@ -28,7 +28,7 @@ import { defineComponent, computed, toRef } from 'vue';
 import { useCurrentTreeNodes } from '../UseCurrentTreeNodes';
 import NodeCheckbox from './NodeCheckbox.vue';
 import InteractableNode from './InteractableNode.vue';
-import type { TreeNode } from './TreeNode';
+import type { TreeNode, TreeNodeId } from './TreeNode';
 import type { TreeRoot } from '../TreeRoot/TreeRoot';
 import type { PropType } from 'vue';
 
@@ -39,7 +39,7 @@ export default defineComponent({
   },
   props: {
     nodeId: {
-      type: String,
+      type: String as PropType<TreeNodeId>,
       required: true,
     },
     treeRoot: {
diff --git a/src/presentation/components/Scripts/View/Tree/TreeView/Node/NodeCheckbox.vue b/src/presentation/components/Scripts/View/Tree/TreeView/Node/NodeCheckbox.vue
index fe73f84c..df447660 100644
--- a/src/presentation/components/Scripts/View/Tree/TreeView/Node/NodeCheckbox.vue
+++ b/src/presentation/components/Scripts/View/Tree/TreeView/Node/NodeCheckbox.vue
@@ -14,13 +14,13 @@ import { useCurrentTreeNodes } from '../UseCurrentTreeNodes';
 import { useNodeState } from './UseNodeState';
 import { TreeNodeCheckState } from './State/CheckState';
 import type { TreeRoot } from '../TreeRoot/TreeRoot';
-import type { TreeNode } from './TreeNode';
+import type { TreeNode, TreeNodeId } from './TreeNode';
 import type { PropType } from 'vue';
 
 export default defineComponent({
   props: {
     nodeId: {
-      type: String,
+      type: String as PropType<TreeNodeId>,
       required: true,
     },
     treeRoot: {
diff --git a/src/presentation/components/Scripts/View/Tree/TreeView/Node/TreeNode.ts b/src/presentation/components/Scripts/View/Tree/TreeView/Node/TreeNode.ts
index 3442bc39..7e4f8f1a 100644
--- a/src/presentation/components/Scripts/View/Tree/TreeView/Node/TreeNode.ts
+++ b/src/presentation/components/Scripts/View/Tree/TreeView/Node/TreeNode.ts
@@ -1,8 +1,10 @@
 import type { HierarchyAccess, HierarchyReader } from './Hierarchy/HierarchyAccess';
 import type { TreeNodeStateAccess, TreeNodeStateReader } from './State/StateAccess';
 
+export type TreeNodeId = string;
+
 export interface ReadOnlyTreeNode {
-  readonly id: string;
+  readonly id: TreeNodeId;
   readonly state: TreeNodeStateReader;
   readonly hierarchy: HierarchyReader;
   readonly metadata?: object;
diff --git a/src/presentation/components/Scripts/View/Tree/TreeView/Node/TreeNodeManager.ts b/src/presentation/components/Scripts/View/Tree/TreeView/Node/TreeNodeManager.ts
index 118e300d..f0c5669d 100644
--- a/src/presentation/components/Scripts/View/Tree/TreeView/Node/TreeNodeManager.ts
+++ b/src/presentation/components/Scripts/View/Tree/TreeView/Node/TreeNodeManager.ts
@@ -1,6 +1,6 @@
 import { TreeNodeHierarchy } from './Hierarchy/TreeNodeHierarchy';
 import { TreeNodeState } from './State/TreeNodeState';
-import type { TreeNode } from './TreeNode';
+import type { TreeNode, TreeNodeId } from './TreeNode';
 import type { TreeNodeStateAccess } from './State/StateAccess';
 import type { HierarchyAccess } from './Hierarchy/HierarchyAccess';
 
@@ -9,7 +9,7 @@ export class TreeNodeManager implements TreeNode {
 
   public readonly hierarchy: HierarchyAccess;
 
-  constructor(public readonly id: string, public readonly metadata?: object) {
+  constructor(public readonly id: TreeNodeId, public readonly metadata?: object) {
     if (!id) {
       throw new Error('missing id');
     }
diff --git a/src/presentation/components/Scripts/View/Tree/TreeView/TreeRoot/TreeRoot.vue b/src/presentation/components/Scripts/View/Tree/TreeView/TreeRoot/TreeRoot.vue
index 674db3f7..0901d059 100644
--- a/src/presentation/components/Scripts/View/Tree/TreeView/TreeRoot/TreeRoot.vue
+++ b/src/presentation/components/Scripts/View/Tree/TreeView/TreeRoot/TreeRoot.vue
@@ -22,6 +22,7 @@ import {
 } from 'vue';
 import HierarchicalTreeNode from '../Node/HierarchicalTreeNode.vue';
 import { useCurrentTreeNodes } from '../UseCurrentTreeNodes';
+import { type TreeNodeId } from '../Node/TreeNode';
 import type { NodeRenderingStrategy } from '../Rendering/Scheduling/NodeRenderingStrategy';
 import type { TreeRoot } from './TreeRoot';
 import type { PropType } from 'vue';
@@ -43,7 +44,7 @@ export default defineComponent({
   setup(props) {
     const { nodes } = useCurrentTreeNodes(toRef(props, 'treeRoot'));
 
-    const renderedNodeIds = computed<string[]>(() => {
+    const renderedNodeIds = computed<TreeNodeId[]>(() => {
       return nodes
         .value
         .rootNodes
diff --git a/src/presentation/components/Scripts/View/Tree/TreeView/TreeView.vue b/src/presentation/components/Scripts/View/Tree/TreeView/TreeView.vue
index 230ea689..bd19c42c 100644
--- a/src/presentation/components/Scripts/View/Tree/TreeView/TreeView.vue
+++ b/src/presentation/components/Scripts/View/Tree/TreeView/TreeView.vue
@@ -26,6 +26,7 @@ import { useLeafNodeCheckedStateUpdater } from './UseLeafNodeCheckedStateUpdater
 import { useAutoUpdateParentCheckState } from './UseAutoUpdateParentCheckState';
 import { useAutoUpdateChildrenCheckState } from './UseAutoUpdateChildrenCheckState';
 import { useGradualNodeRendering, type NodeRenderingControl } from './Rendering/UseGradualNodeRendering';
+import { type TreeNodeId } from './Node/TreeNode';
 import type { TreeNodeStateChangedEmittedEvent } from './Bindings/TreeNodeStateChangedEmittedEvent';
 import type { TreeInputNodeData } from './Bindings/TreeInputNodeData';
 import type { TreeViewFilterEvent } from './Bindings/TreeInputFilterEvent';
@@ -45,7 +46,7 @@ export default defineComponent({
       default: () => undefined,
     },
     selectedLeafNodeIds: {
-      type: Array as PropType<ReadonlyArray<string>>,
+      type: Array as PropType<ReadonlyArray<TreeNodeId>>,
       default: () => [],
     },
   },
diff --git a/src/presentation/components/Scripts/View/Tree/TreeViewAdapter/CategoryNodeMetadataConverter.ts b/src/presentation/components/Scripts/View/Tree/TreeViewAdapter/CategoryNodeMetadataConverter.ts
index b7354e5d..c4639892 100644
--- a/src/presentation/components/Scripts/View/Tree/TreeViewAdapter/CategoryNodeMetadataConverter.ts
+++ b/src/presentation/components/Scripts/View/Tree/TreeViewAdapter/CategoryNodeMetadataConverter.ts
@@ -1,14 +1,17 @@
 import type { Category } from '@/domain/Executables/Category/Category';
-import type { ICategoryCollection } from '@/domain/ICategoryCollection';
+import type { ICategoryCollection } from '@/domain/Collection/ICategoryCollection';
 import type { Script } from '@/domain/Executables/Script/Script';
+import type { ExecutableId } from '@/domain/Executables/Identifiable';
+import type { Executable } from '@/domain/Executables/Executable';
 import { type NodeMetadata, NodeType } from '../NodeContent/NodeMetadata';
+import type { TreeNodeId } from '../TreeView/Node/TreeNode';
 
 export function parseAllCategories(collection: ICategoryCollection): NodeMetadata[] {
   return createCategoryNodes(collection.actions);
 }
 
 export function parseSingleCategory(
-  categoryId: number,
+  categoryId: ExecutableId,
   collection: ICategoryCollection,
 ): NodeMetadata[] {
   const category = collection.getCategory(categoryId);
@@ -16,27 +19,19 @@ export function parseSingleCategory(
   return tree;
 }
 
-export function getScriptNodeId(script: Script): string {
-  return script.id;
+export function createNodeIdForExecutable(executable: Executable): TreeNodeId {
+  return executable.executableId;
 }
 
-export function getScriptId(nodeId: string): string {
+export function createExecutableIdFromNodeId(nodeId: TreeNodeId): ExecutableId {
   return nodeId;
 }
 
-export function getCategoryId(nodeId: string): number {
-  return +nodeId;
-}
-
-export function getCategoryNodeId(category: Category): string {
-  return `${category.id}`;
-}
-
 function parseCategoryRecursively(
   parentCategory: Category,
 ): NodeMetadata[] {
   return [
-    ...createCategoryNodes(parentCategory.subCategories),
+    ...createCategoryNodes(parentCategory.subcategories),
     ...createScriptNodes(parentCategory.scripts),
   ];
 }
@@ -57,7 +52,7 @@ function convertCategoryToNode(
   children: readonly NodeMetadata[],
 ): NodeMetadata {
   return {
-    id: getCategoryNodeId(category),
+    id: createNodeIdForExecutable(category),
     type: NodeType.Category,
     text: category.name,
     children,
@@ -68,7 +63,7 @@ function convertCategoryToNode(
 
 function convertScriptToNode(script: Script): NodeMetadata {
   return {
-    id: getScriptNodeId(script),
+    id: createNodeIdForExecutable(script),
     type: NodeType.Script,
     text: script.name,
     children: [],
diff --git a/src/presentation/components/Scripts/View/Tree/TreeViewAdapter/UseSelectedScriptNodeIds.ts b/src/presentation/components/Scripts/View/Tree/TreeViewAdapter/UseSelectedScriptNodeIds.ts
index e60ebc49..1325cbf6 100644
--- a/src/presentation/components/Scripts/View/Tree/TreeViewAdapter/UseSelectedScriptNodeIds.ts
+++ b/src/presentation/components/Scripts/View/Tree/TreeViewAdapter/UseSelectedScriptNodeIds.ts
@@ -2,20 +2,21 @@ import {
   computed, shallowReadonly,
 } from 'vue';
 import type { useUserSelectionState } from '@/presentation/components/Shared/Hooks/UseUserSelectionState';
-import { getScriptNodeId } from './CategoryNodeMetadataConverter';
+import { createNodeIdForExecutable } from './CategoryNodeMetadataConverter';
+import type { TreeNodeId } from '../TreeView/Node/TreeNode';
 
 export function useSelectedScriptNodeIds(
   useSelectionStateHook: ReturnType<typeof useUserSelectionState>,
-  scriptNodeIdParser = getScriptNodeId,
+  convertToNodeId = createNodeIdForExecutable,
 ) {
   const { currentSelection } = useSelectionStateHook;
 
-  const selectedNodeIds = computed<readonly string[]>(() => {
+  const selectedNodeIds = computed<readonly TreeNodeId[]>(() => {
     return currentSelection
       .value
       .scripts
       .selectedScripts
-      .map((selected) => scriptNodeIdParser(selected.script));
+      .map((selected) => convertToNodeId(selected.script));
   });
 
   return {
diff --git a/src/presentation/components/Scripts/View/Tree/TreeViewAdapter/UseTreeViewFilterEvent.ts b/src/presentation/components/Scripts/View/Tree/TreeViewAdapter/UseTreeViewFilterEvent.ts
index d9088f64..23f1e0e7 100644
--- a/src/presentation/components/Scripts/View/Tree/TreeViewAdapter/UseTreeViewFilterEvent.ts
+++ b/src/presentation/components/Scripts/View/Tree/TreeViewAdapter/UseTreeViewFilterEvent.ts
@@ -1,16 +1,15 @@
 import {
   type Ref, shallowReadonly, shallowRef,
 } from 'vue';
-import type { Script } from '@/domain/Executables/Script/Script';
 import type { Category } from '@/domain/Executables/Category/Category';
 import { injectKey } from '@/presentation/injectionSymbols';
 import type { ReadonlyFilterContext } from '@/application/Context/State/Filter/FilterContext';
 import type { FilterResult } from '@/application/Context/State/Filter/Result/FilterResult';
+import type { ExecutableId } from '@/domain/Executables/Identifiable';
+import type { Executable } from '@/domain/Executables/Executable';
 import { type TreeViewFilterEvent, createFilterRemovedEvent, createFilterTriggeredEvent } from '../TreeView/Bindings/TreeInputFilterEvent';
-import { getNodeMetadata } from './TreeNodeMetadataConverter';
-import { getCategoryNodeId, getScriptNodeId } from './CategoryNodeMetadataConverter';
-import type { NodeMetadata } from '../NodeContent/NodeMetadata';
-import type { ReadOnlyTreeNode } from '../TreeView/Node/TreeNode';
+import { createExecutableIdFromNodeId } from './CategoryNodeMetadataConverter';
+import type { ReadOnlyTreeNode, TreeNodeId } from '../TreeView/Node/TreeNode';
 
 type TreeNodeFilterResultPredicate = (
   node: ReadOnlyTreeNode,
@@ -24,7 +23,7 @@ export function useTreeViewFilterEvent() {
   const latestFilterEvent = shallowRef<TreeViewFilterEvent | undefined>(undefined);
 
   const treeNodePredicate: TreeNodeFilterResultPredicate = (node, filterResult) => filterMatches(
-    getNodeMetadata(node),
+    node.id,
     filterResult,
   );
 
@@ -71,15 +70,17 @@ function createFilterEvent(
   );
 }
 
-function filterMatches(node: NodeMetadata, filter: FilterResult): boolean {
-  return containsScript(node, filter.scriptMatches)
-    || containsCategory(node, filter.categoryMatches);
+function filterMatches(nodeId: TreeNodeId, filter: FilterResult): boolean {
+  const executableId = createExecutableIdFromNodeId(nodeId);
+  return containsExecutable(executableId, filter.scriptMatches)
+    || containsExecutable(executableId, filter.categoryMatches);
 }
 
-function containsScript(expected: NodeMetadata, scripts: readonly Script[]) {
-  return scripts.some((existing: Script) => expected.id === getScriptNodeId(existing));
-}
-
-function containsCategory(expected: NodeMetadata, categories: readonly Category[]) {
-  return categories.some((existing: Category) => expected.id === getCategoryNodeId(existing));
+function containsExecutable(
+  expectedId: ExecutableId,
+  executables: readonly Executable[],
+): boolean {
+  return executables.some(
+    (existing: Category) => existing.executableId === expectedId,
+  );
 }
diff --git a/src/presentation/components/Scripts/View/Tree/TreeViewAdapter/UseTreeViewNodeInput.ts b/src/presentation/components/Scripts/View/Tree/TreeViewAdapter/UseTreeViewNodeInput.ts
index 160d9ee1..693de40d 100644
--- a/src/presentation/components/Scripts/View/Tree/TreeViewAdapter/UseTreeViewNodeInput.ts
+++ b/src/presentation/components/Scripts/View/Tree/TreeViewAdapter/UseTreeViewNodeInput.ts
@@ -1,15 +1,16 @@
 import {
   type Ref, computed, shallowReadonly,
 } from 'vue';
-import type { ICategoryCollection } from '@/domain/ICategoryCollection';
+import type { ICategoryCollection } from '@/domain/Collection/ICategoryCollection';
 import { injectKey } from '@/presentation/injectionSymbols';
+import type { ExecutableId } from '@/domain/Executables/Identifiable';
 import { parseSingleCategory, parseAllCategories } from './CategoryNodeMetadataConverter';
 import { convertToNodeInput } from './TreeNodeMetadataConverter';
 import type { TreeInputNodeData } from '../TreeView/Bindings/TreeInputNodeData';
 import type { NodeMetadata } from '../NodeContent/NodeMetadata';
 
 export function useTreeViewNodeInput(
-  categoryIdRef: Readonly<Ref<number | undefined>>,
+  categoryIdRef: Readonly<Ref<ExecutableId | undefined>>,
   parser: CategoryNodeParser = {
     parseSingle: parseSingleCategory,
     parseAll: parseAllCategories,
@@ -30,7 +31,7 @@ export function useTreeViewNodeInput(
 }
 
 function parseNodes(
-  categoryId: number | undefined,
+  categoryId: ExecutableId | undefined,
   categoryCollection: ICategoryCollection,
   parser: CategoryNodeParser,
 ): NodeMetadata[] {
diff --git a/tests/integration/presentation/components/Scripts/View/Tree/NodeContent/Markdown/CompositeMarkdownRenderer.spec.ts b/tests/integration/presentation/components/Scripts/View/Tree/NodeContent/Markdown/CompositeMarkdownRenderer.spec.ts
index decc2495..b0e161ab 100644
--- a/tests/integration/presentation/components/Scripts/View/Tree/NodeContent/Markdown/CompositeMarkdownRenderer.spec.ts
+++ b/tests/integration/presentation/components/Scripts/View/Tree/NodeContent/Markdown/CompositeMarkdownRenderer.spec.ts
@@ -225,7 +225,7 @@ function collectAllDocumentedExecutables(): DocumentedExecutable[] {
   ]);
   const allDocumentedExecutables = allExecutables.filter((e) => e.docs.length > 0);
   return allDocumentedExecutables.map((executable): DocumentedExecutable => ({
-    executableLabel: `${executable.name} (${executable.id})`,
+    executableLabel: `${executable.name} (${executable.executableId})`,
     docs: executable.docs.join('\n'),
   }));
 }
diff --git a/tests/unit/application/Context/ApplicationContextFactory.spec.ts b/tests/unit/application/Context/ApplicationContextFactory.spec.ts
index ee1332cd..6909ef90 100644
--- a/tests/unit/application/Context/ApplicationContextFactory.spec.ts
+++ b/tests/unit/application/Context/ApplicationContextFactory.spec.ts
@@ -1,6 +1,6 @@
 import { describe, it, expect } from 'vitest';
 import { OperatingSystem } from '@/domain/OperatingSystem';
-import type { ICategoryCollection } from '@/domain/ICategoryCollection';
+import type { ICategoryCollection } from '@/domain/Collection/ICategoryCollection';
 import { buildContext } from '@/application/Context/ApplicationContextFactory';
 import type { IApplicationFactory } from '@/application/IApplicationFactory';
 import type { IApplication } from '@/domain/IApplication';
diff --git a/tests/unit/application/Context/State/CategoryCollectionState.spec.ts b/tests/unit/application/Context/State/CategoryCollectionState.spec.ts
index 8ff028cb..cd91a9e6 100644
--- a/tests/unit/application/Context/State/CategoryCollectionState.spec.ts
+++ b/tests/unit/application/Context/State/CategoryCollectionState.spec.ts
@@ -4,7 +4,7 @@ import { CategoryCollectionState } from '@/application/Context/State/CategoryCol
 import { OperatingSystem } from '@/domain/OperatingSystem';
 import { CategoryCollectionStub } from '@tests/unit/shared/Stubs/CategoryCollectionStub';
 import { ScriptingDefinitionStub } from '@tests/unit/shared/Stubs/ScriptingDefinitionStub';
-import type { ICategoryCollection } from '@/domain/ICategoryCollection';
+import type { ICategoryCollection } from '@/domain/Collection/ICategoryCollection';
 import { ApplicationCodeStub } from '@tests/unit/shared/Stubs/ApplicationCodeStub';
 import type { IScriptingDefinition } from '@/domain/IScriptingDefinition';
 import { expectExists } from '@tests/shared/Assertions/ExpectExists';
diff --git a/tests/unit/application/Context/State/Filter/AdaptiveFilterContext.spec.ts b/tests/unit/application/Context/State/Filter/AdaptiveFilterContext.spec.ts
index 0a12d1ea..a8e487bc 100644
--- a/tests/unit/application/Context/State/Filter/AdaptiveFilterContext.spec.ts
+++ b/tests/unit/application/Context/State/Filter/AdaptiveFilterContext.spec.ts
@@ -8,7 +8,7 @@ import { FilterResultStub } from '@tests/unit/shared/Stubs/FilterResultStub';
 import { FilterStrategyStub } from '@tests/unit/shared/Stubs/FilterStrategyStub';
 import type { FilterStrategy } from '@/application/Context/State/Filter/Strategy/FilterStrategy';
 import type { FilterResult } from '@/application/Context/State/Filter/Result/FilterResult';
-import type { ICategoryCollection } from '@/domain/ICategoryCollection';
+import type { ICategoryCollection } from '@/domain/Collection/ICategoryCollection';
 
 describe('AdaptiveFilterContext', () => {
   describe('clearFilter', () => {
diff --git a/tests/unit/application/Context/State/Filter/Result/AppliedFilterResult.spec.ts b/tests/unit/application/Context/State/Filter/Result/AppliedFilterResult.spec.ts
index bdfc8a85..206944b9 100644
--- a/tests/unit/application/Context/State/Filter/Result/AppliedFilterResult.spec.ts
+++ b/tests/unit/application/Context/State/Filter/Result/AppliedFilterResult.spec.ts
@@ -48,7 +48,7 @@ describe('AppliedFilterResult', () => {
       const expected = true;
       const result = new ResultBuilder()
         .withScriptMatches([])
-        .withCategoryMatches([new CategoryStub(5)])
+        .withCategoryMatches([new CategoryStub('matched-category-id')])
         .build();
       // act
       const actual = result.hasAnyMatches();
@@ -58,8 +58,8 @@ describe('AppliedFilterResult', () => {
       // arrange
       const expected = true;
       const result = new ResultBuilder()
-        .withScriptMatches([new ScriptStub('id')])
-        .withCategoryMatches([new CategoryStub(5)])
+        .withScriptMatches([new ScriptStub('matched-script-id')])
+        .withCategoryMatches([new CategoryStub('matched-category-id')])
         .build();
       // act
       const actual = result.hasAnyMatches();
@@ -69,9 +69,13 @@ describe('AppliedFilterResult', () => {
 });
 
 class ResultBuilder {
-  private scriptMatches: readonly Script[] = [new ScriptStub('id')];
+  private scriptMatches: readonly Script[] = [
+    new ScriptStub(`[${ResultBuilder.name}]matched-script-id`),
+  ];
 
-  private categoryMatches: readonly Category[] = [new CategoryStub(5)];
+  private categoryMatches: readonly Category[] = [
+    new CategoryStub(`[${ResultBuilder.name}]matched-category-id`),
+  ];
 
   private query: string = `[${ResultBuilder.name}]query`;
 
diff --git a/tests/unit/application/Context/State/Filter/Strategy/LinearFilterStrategy.spec.ts b/tests/unit/application/Context/State/Filter/Strategy/LinearFilterStrategy.spec.ts
index e2639a52..9a3bcab0 100644
--- a/tests/unit/application/Context/State/Filter/Strategy/LinearFilterStrategy.spec.ts
+++ b/tests/unit/application/Context/State/Filter/Strategy/LinearFilterStrategy.spec.ts
@@ -2,7 +2,7 @@ import { describe, it, expect } from 'vitest';
 import { CategoryStub } from '@tests/unit/shared/Stubs/CategoryStub';
 import { ScriptStub } from '@tests/unit/shared/Stubs/ScriptStub';
 import { CategoryCollectionStub } from '@tests/unit/shared/Stubs/CategoryCollectionStub';
-import type { ICategoryCollection } from '@/domain/ICategoryCollection';
+import type { ICategoryCollection } from '@/domain/Collection/ICategoryCollection';
 import type { Category } from '@/domain/Executables/Category/Category';
 import type { Script } from '@/domain/Executables/Script/Script';
 import type { FilterResult } from '@/application/Context/State/Filter/Result/FilterResult';
@@ -37,7 +37,10 @@ describe('LinearFilterStrategy', () => {
         // arrange
         const matchingFilter = 'matching filter';
         const collection = new CategoryCollectionStub()
-          .withAction(new CategoryStub(2).withScript(createMatchingScript(matchingFilter)));
+          .withAction(
+            new CategoryStub('parent-category-of-matching-script')
+              .withScript(createMatchingScript(matchingFilter)),
+          );
         const strategy = new FilterStrategyTestBuilder()
           .withFilter(matchingFilter)
           .withCollection(collection);
@@ -64,7 +67,7 @@ describe('LinearFilterStrategy', () => {
         const matchingFilter = 'matching filter';
         const collection = new CategoryCollectionStub()
           .withAction(createMatchingCategory(matchingFilter))
-          .withAction(new CategoryStub(2).withScript(createMatchingScript(matchingFilter)));
+          .withAction(new CategoryStub('matching-script-parent').withScript(createMatchingScript(matchingFilter)));
         const strategy = new FilterStrategyTestBuilder()
           .withFilter(matchingFilter)
           .withCollection(collection);
@@ -120,7 +123,7 @@ describe('LinearFilterStrategy', () => {
             // arrange
             const expectedMatches = [matchingScript];
             const collection = new CategoryCollectionStub()
-              .withAction(new CategoryStub(33).withScript(matchingScript));
+              .withAction(new CategoryStub('matching-script-parent').withScript(matchingScript));
             const strategy = new FilterStrategyTestBuilder()
               .withFilter(filter)
               .withCollection(collection);
@@ -140,7 +143,7 @@ describe('LinearFilterStrategy', () => {
         ];
         const expectedMatches = [...matchingScripts];
         const collection = new CategoryCollectionStub()
-          .withAction(new CategoryStub(0).withScripts(...matchingScripts));
+          .withAction(new CategoryStub('matching-scripts-parent').withScripts(...matchingScripts));
         const strategy = new FilterStrategyTestBuilder()
           .withFilter(filter)
           .withCollection(collection);
@@ -171,12 +174,12 @@ describe('LinearFilterStrategy', () => {
           {
             description: 'match with case-insensitive name',
             filter: 'Hello WoRLD',
-            matchingCategory: new CategoryStub(55).withName('HELLO world'),
+            matchingCategory: new CategoryStub('matching-script-parent').withName('HELLO world'),
           },
           {
             description: 'case-sensitive documentation',
             filter: 'Hello WoRLD',
-            matchingCategory: new CategoryStub(55).withDocs(['unrelated-docs', 'HELLO world']),
+            matchingCategory: new CategoryStub('matching-script-parent').withDocs(['unrelated-docs', 'HELLO world']),
           },
         ];
         testScenarios.forEach(({
@@ -230,7 +233,7 @@ function createMatchingScript(
 function createMatchingCategory(
   matchingFilter: string,
 ): CategoryStub {
-  return new CategoryStub(1)
+  return new CategoryStub('matching-category')
     .withName(matchingFilter)
     .withDocs([matchingFilter]);
 }
diff --git a/tests/unit/application/Context/State/Selection/Category/ScriptToCategorySelectionMapper.spec.ts b/tests/unit/application/Context/State/Selection/Category/ScriptToCategorySelectionMapper.spec.ts
index 7c14ce4b..c2c9f1ec 100644
--- a/tests/unit/application/Context/State/Selection/Category/ScriptToCategorySelectionMapper.spec.ts
+++ b/tests/unit/application/Context/State/Selection/Category/ScriptToCategorySelectionMapper.spec.ts
@@ -2,14 +2,13 @@ import { CategoryStub } from '@tests/unit/shared/Stubs/CategoryStub';
 import { CategoryCollectionStub } from '@tests/unit/shared/Stubs/CategoryCollectionStub';
 import { ScriptStub } from '@tests/unit/shared/Stubs/ScriptStub';
 import type { ScriptSelection } from '@/application/Context/State/Selection/Script/ScriptSelection';
-import type { ICategoryCollection } from '@/domain/ICategoryCollection';
+import type { ICategoryCollection } from '@/domain/Collection/ICategoryCollection';
 import { ScriptToCategorySelectionMapper } from '@/application/Context/State/Selection/Category/ScriptToCategorySelectionMapper';
 import { ScriptSelectionStub } from '@tests/unit/shared/Stubs/ScriptSelectionStub';
 import type { CategorySelectionChange } from '@/application/Context/State/Selection/Category/CategorySelectionChange';
 import type { ScriptSelectionChange, ScriptSelectionChangeCommand } from '@/application/Context/State/Selection/Script/ScriptSelectionChange';
 import { expectExists } from '@tests/shared/Assertions/ExpectExists';
-import type { Category } from '@/domain/Executables/Category/Category';
-import type { Script } from '@/domain/Executables/Script/Script';
+import type { ExecutableId } from '@/domain/Executables/Identifiable';
 
 describe('ScriptToCategorySelectionMapper', () => {
   describe('areAllScriptsSelected', () => {
@@ -65,18 +64,18 @@ describe('ScriptToCategorySelectionMapper', () => {
       readonly description: string;
       readonly changes: readonly CategorySelectionChange[];
       readonly categories: ReadonlyArray<{
-        readonly categoryId: Category['id'],
-        readonly scriptIds: readonly Script['id'][],
+        readonly categoryId: ExecutableId,
+        readonly scriptIds: readonly ExecutableId[],
       }>;
       readonly expected: readonly ScriptSelectionChange[],
     }> = [
       {
         description: 'single script: select without revert',
         categories: [
-          { categoryId: 1, scriptIds: ['single-script'] },
+          { categoryId: 'category-1', scriptIds: ['single-script'] },
         ],
         changes: [
-          { categoryId: 1, newStatus: { isSelected: true, isReverted: false } },
+          { categoryId: 'category-1', newStatus: { isSelected: true, isReverted: false } },
         ],
         expected: [
           { scriptId: 'single-script', newStatus: { isSelected: true, isReverted: false } },
@@ -85,12 +84,12 @@ describe('ScriptToCategorySelectionMapper', () => {
       {
         description: 'multiple scripts: select without revert',
         categories: [
-          { categoryId: 1, scriptIds: ['script1-cat1', 'script2-cat1'] },
-          { categoryId: 2, scriptIds: ['script3-cat2'] },
+          { categoryId: 'category-1', scriptIds: ['script1-cat1', 'script2-cat1'] },
+          { categoryId: 'category-2', scriptIds: ['script3-cat2'] },
         ],
         changes: [
-          { categoryId: 1, newStatus: { isSelected: true, isReverted: false } },
-          { categoryId: 2, newStatus: { isSelected: true, isReverted: false } },
+          { categoryId: 'category-1', newStatus: { isSelected: true, isReverted: false } },
+          { categoryId: 'category-2', newStatus: { isSelected: true, isReverted: false } },
         ],
         expected: [
           { scriptId: 'script1-cat1', newStatus: { isSelected: true, isReverted: false } },
@@ -101,10 +100,10 @@ describe('ScriptToCategorySelectionMapper', () => {
       {
         description: 'single script: select with revert',
         categories: [
-          { categoryId: 1, scriptIds: ['single-script'] },
+          { categoryId: 'category-1', scriptIds: ['single-script'] },
         ],
         changes: [
-          { categoryId: 1, newStatus: { isSelected: true, isReverted: true } },
+          { categoryId: 'category-1', newStatus: { isSelected: true, isReverted: true } },
         ],
         expected: [
           { scriptId: 'single-script', newStatus: { isSelected: true, isReverted: true } },
@@ -113,14 +112,14 @@ describe('ScriptToCategorySelectionMapper', () => {
       {
         description: 'multiple scripts: select with revert',
         categories: [
-          { categoryId: 1, scriptIds: ['script-1-cat-1'] },
-          { categoryId: 2, scriptIds: ['script-2-cat-2'] },
-          { categoryId: 3, scriptIds: ['script-3-cat-3'] },
+          { categoryId: 'category-1', scriptIds: ['script-1-cat-1'] },
+          { categoryId: 'category-2', scriptIds: ['script-2-cat-2'] },
+          { categoryId: 'category-3', scriptIds: ['script-3-cat-3'] },
         ],
         changes: [
-          { categoryId: 1, newStatus: { isSelected: true, isReverted: true } },
-          { categoryId: 2, newStatus: { isSelected: true, isReverted: true } },
-          { categoryId: 3, newStatus: { isSelected: true, isReverted: true } },
+          { categoryId: 'category-1', newStatus: { isSelected: true, isReverted: true } },
+          { categoryId: 'category-2', newStatus: { isSelected: true, isReverted: true } },
+          { categoryId: 'category-3', newStatus: { isSelected: true, isReverted: true } },
         ],
         expected: [
           { scriptId: 'script-1-cat-1', newStatus: { isSelected: true, isReverted: true } },
@@ -131,10 +130,10 @@ describe('ScriptToCategorySelectionMapper', () => {
       {
         description: 'single script: deselect',
         categories: [
-          { categoryId: 1, scriptIds: ['single-script'] },
+          { categoryId: 'category-1', scriptIds: ['single-script'] },
         ],
         changes: [
-          { categoryId: 1, newStatus: { isSelected: false } },
+          { categoryId: 'category-1', newStatus: { isSelected: false } },
         ],
         expected: [
           { scriptId: 'single-script', newStatus: { isSelected: false } },
@@ -143,12 +142,12 @@ describe('ScriptToCategorySelectionMapper', () => {
       {
         description: 'multiple scripts: deselect',
         categories: [
-          { categoryId: 1, scriptIds: ['script-1-cat1'] },
-          { categoryId: 2, scriptIds: ['script-2-cat2'] },
+          { categoryId: 'category-1', scriptIds: ['script-1-cat1'] },
+          { categoryId: 'category-2', scriptIds: ['script-2-cat2'] },
         ],
         changes: [
-          { categoryId: 1, newStatus: { isSelected: false } },
-          { categoryId: 2, newStatus: { isSelected: false } },
+          { categoryId: 'category-1', newStatus: { isSelected: false } },
+          { categoryId: 'category-2', newStatus: { isSelected: false } },
         ],
         expected: [
           { scriptId: 'script-1-cat1', newStatus: { isSelected: false } },
@@ -158,14 +157,14 @@ describe('ScriptToCategorySelectionMapper', () => {
       {
         description: 'mixed operations (select, revert, deselect)',
         categories: [
-          { categoryId: 1, scriptIds: ['to-revert'] },
-          { categoryId: 2, scriptIds: ['not-revert'] },
-          { categoryId: 3, scriptIds: ['to-deselect'] },
+          { categoryId: 'category-1', scriptIds: ['to-revert'] },
+          { categoryId: 'category-2', scriptIds: ['not-revert'] },
+          { categoryId: 'category-3', scriptIds: ['to-deselect'] },
         ],
         changes: [
-          { categoryId: 1, newStatus: { isSelected: true, isReverted: true } },
-          { categoryId: 2, newStatus: { isSelected: true, isReverted: false } },
-          { categoryId: 3, newStatus: { isSelected: false } },
+          { categoryId: 'category-1', newStatus: { isSelected: true, isReverted: true } },
+          { categoryId: 'category-2', newStatus: { isSelected: true, isReverted: false } },
+          { categoryId: 'category-3', newStatus: { isSelected: false } },
         ],
         expected: [
           { scriptId: 'to-revert', newStatus: { isSelected: true, isReverted: true } },
@@ -176,12 +175,12 @@ describe('ScriptToCategorySelectionMapper', () => {
       {
         description: 'affecting selected categories only',
         categories: [
-          { categoryId: 1, scriptIds: ['relevant-1', 'relevant-2'] },
-          { categoryId: 2, scriptIds: ['not-relevant-1', 'not-relevant-2'] },
-          { categoryId: 3, scriptIds: ['not-relevant-3', 'not-relevant-4'] },
+          { categoryId: 'category-1', scriptIds: ['relevant-1', 'relevant-2'] },
+          { categoryId: 'category-2', scriptIds: ['not-relevant-1', 'not-relevant-2'] },
+          { categoryId: 'category-3', scriptIds: ['not-relevant-3', 'not-relevant-4'] },
         ],
         changes: [
-          { categoryId: 1, newStatus: { isSelected: true, isReverted: true } },
+          { categoryId: 'category-1', newStatus: { isSelected: true, isReverted: true } },
         ],
         expected: [
           { scriptId: 'relevant-1', newStatus: { isSelected: true, isReverted: true } },
@@ -198,7 +197,7 @@ describe('ScriptToCategorySelectionMapper', () => {
         const sut = new ScriptToCategorySelectionMapperBuilder()
           .withScriptSelection(scriptSelectionStub)
           .withCollection(new CategoryCollectionStub().withAction(
-            new CategoryStub(99)
+            new CategoryStub('single-parent-category-action')
               // Register scripts to test for nested items
               .withAllScriptIdsRecursively(...categories.flatMap((c) => c.scriptIds))
               .withCategories(...categories.map(
@@ -256,7 +255,7 @@ function setupTestWithPreselectedScripts(options: {
     new ScriptStub('third-script'),
   ];
   const preselectedScripts = options.preselect(allScripts);
-  const category = new CategoryStub(1)
+  const category = new CategoryStub('single-parent-category-action')
     .withAllScriptsRecursively(...allScripts); // Register scripts to test for nested items
   const collection = new CategoryCollectionStub().withAction(category);
   const sut = new ScriptToCategorySelectionMapperBuilder()
diff --git a/tests/unit/application/Context/State/Selection/Script/DebouncedScriptSelection.spec.ts b/tests/unit/application/Context/State/Selection/Script/DebouncedScriptSelection.spec.ts
index 3d840137..b0ef2cdc 100644
--- a/tests/unit/application/Context/State/Selection/Script/DebouncedScriptSelection.spec.ts
+++ b/tests/unit/application/Context/State/Selection/Script/DebouncedScriptSelection.spec.ts
@@ -4,7 +4,7 @@ import { CategoryStub } from '@tests/unit/shared/Stubs/CategoryStub';
 import { CategoryCollectionStub } from '@tests/unit/shared/Stubs/CategoryCollectionStub';
 import { SelectedScriptStub } from '@tests/unit/shared/Stubs/SelectedScriptStub';
 import { ScriptStub } from '@tests/unit/shared/Stubs/ScriptStub';
-import type { ICategoryCollection } from '@/domain/ICategoryCollection';
+import type { ICategoryCollection } from '@/domain/Collection/ICategoryCollection';
 import type { SelectedScript } from '@/application/Context/State/Selection/Script/SelectedScript';
 import { BatchedDebounceStub } from '@tests/unit/shared/Stubs/BatchedDebounceStub';
 import type { ScriptSelectionChange, ScriptSelectionChangeCommand } from '@/application/Context/State/Selection/Script/ScriptSelectionChange';
@@ -104,7 +104,7 @@ describe('DebouncedScriptSelection', () => {
       const { scriptSelection, unselectedScripts } = setupTestWithPreselectedScripts({
         preselect: (allScripts) => [allScripts[0]],
       });
-      const scriptIdToCheck = unselectedScripts[0].id;
+      const scriptIdToCheck = unselectedScripts[0].executableId;
       // act
       const actual = scriptSelection.isSelected(scriptIdToCheck);
       // assert
@@ -300,7 +300,10 @@ describe('DebouncedScriptSelection', () => {
           preselect: (allScripts) => [allScripts[0], allScripts[1]]
             .map((s) => s.toSelectedScript()),
           getChanges: (allScripts) => [
-            { scriptId: allScripts[2].id, newStatus: { isReverted: true, isSelected: true } },
+            {
+              scriptId: allScripts[2].executableId,
+              newStatus: { isReverted: true, isSelected: true },
+            },
           ],
           getExpectedFinalSelection: (allScripts) => [
             allScripts[0].toSelectedScript(),
@@ -313,7 +316,10 @@ describe('DebouncedScriptSelection', () => {
           preselect: (allScripts) => [allScripts[0], allScripts[1]]
             .map((s) => s.toSelectedScript()),
           getChanges: (allScripts) => [
-            { scriptId: allScripts[2].id, newStatus: { isReverted: false, isSelected: true } },
+            {
+              scriptId: allScripts[2].executableId,
+              newStatus: { isReverted: false, isSelected: true },
+            },
           ],
           getExpectedFinalSelection: (allScripts) => [
             allScripts[0].toSelectedScript(),
@@ -326,7 +332,7 @@ describe('DebouncedScriptSelection', () => {
           preselect: (allScripts) => [allScripts[0], allScripts[1]]
             .map((s) => s.toSelectedScript()),
           getChanges: (allScripts) => [
-            { scriptId: allScripts[0].id, newStatus: { isSelected: false } },
+            { scriptId: allScripts[0].executableId, newStatus: { isSelected: false } },
           ],
           getExpectedFinalSelection: (allScripts) => [
             allScripts[1].toSelectedScript(),
@@ -339,7 +345,10 @@ describe('DebouncedScriptSelection', () => {
             allScripts[1].toSelectedScript(),
           ],
           getChanges: (allScripts) => [
-            { scriptId: allScripts[0].id, newStatus: { isSelected: true, isReverted: true } },
+            {
+              scriptId: allScripts[0].executableId,
+              newStatus: { isSelected: true, isReverted: true },
+            },
           ],
           getExpectedFinalSelection: (allScripts) => [
             allScripts[0].toSelectedScript().withRevert(true),
@@ -353,7 +362,10 @@ describe('DebouncedScriptSelection', () => {
             allScripts[1].toSelectedScript(),
           ],
           getChanges: (allScripts) => [
-            { scriptId: allScripts[0].id, newStatus: { isSelected: true, isReverted: false } },
+            {
+              scriptId: allScripts[0].executableId,
+              newStatus: { isSelected: true, isReverted: false },
+            },
           ],
           getExpectedFinalSelection: (allScripts) => [
             allScripts[0].toSelectedScript().withRevert(false),
@@ -367,9 +379,18 @@ describe('DebouncedScriptSelection', () => {
             allScripts[2].toSelectedScript(), // remove
           ],
           getChanges: (allScripts) => [
-            { scriptId: allScripts[0].id, newStatus: { isSelected: true, isReverted: false } },
-            { scriptId: allScripts[1].id, newStatus: { isSelected: true, isReverted: true } },
-            { scriptId: allScripts[2].id, newStatus: { isSelected: false } },
+            {
+              scriptId: allScripts[0].executableId,
+              newStatus: { isSelected: true, isReverted: false },
+            },
+            {
+              scriptId: allScripts[1].executableId,
+              newStatus: { isSelected: true, isReverted: true },
+            },
+            {
+              scriptId: allScripts[2].executableId,
+              newStatus: { isSelected: false },
+            },
           ],
           getExpectedFinalSelection: (allScripts) => [
             allScripts[0].toSelectedScript().withRevert(false),
@@ -408,7 +429,10 @@ describe('DebouncedScriptSelection', () => {
           description: 'does not change selection for an already selected script',
           preselect: (allScripts) => [allScripts[0].toSelectedScript().withRevert(true)],
           getChanges: (allScripts) => [
-            { scriptId: allScripts[0].id, newStatus: { isReverted: true, isSelected: true } },
+            {
+              scriptId: allScripts[0].executableId,
+              newStatus: { isReverted: true, isSelected: true },
+            },
           ],
         },
         {
@@ -416,15 +440,21 @@ describe('DebouncedScriptSelection', () => {
           preselect: (allScripts) => [allScripts[0], allScripts[1]]
             .map((s) => s.toSelectedScript()),
           getChanges: (allScripts) => [
-            { scriptId: allScripts[2].id, newStatus: { isSelected: false } },
+            { scriptId: allScripts[2].executableId, newStatus: { isSelected: false } },
           ],
         },
         {
           description: 'handles no mutations for mixed unchanged operations',
           preselect: (allScripts) => [allScripts[0].toSelectedScript().withRevert(false)],
           getChanges: (allScripts) => [
-            { scriptId: allScripts[0].id, newStatus: { isSelected: true, isReverted: false } },
-            { scriptId: allScripts[1].id, newStatus: { isSelected: false } },
+            {
+              scriptId: allScripts[0].executableId,
+              newStatus: { isSelected: true, isReverted: false },
+            },
+            {
+              scriptId: allScripts[1].executableId,
+              newStatus: { isSelected: false },
+            },
           ],
         },
       ];
@@ -459,7 +489,7 @@ describe('DebouncedScriptSelection', () => {
           .build();
         const expectedCommand: ScriptSelectionChangeCommand = {
           changes: [
-            { scriptId: script.id, newStatus: { isReverted: true, isSelected: true } },
+            { scriptId: script.executableId, newStatus: { isReverted: true, isSelected: true } },
           ],
         };
         // act
@@ -481,7 +511,7 @@ describe('DebouncedScriptSelection', () => {
         // act
         selection.processChanges({
           changes: [
-            { scriptId: script.id, newStatus: { isReverted: true, isSelected: true } },
+            { scriptId: script.executableId, newStatus: { isReverted: true, isSelected: true } },
           ],
         });
         // assert
@@ -502,7 +532,7 @@ describe('DebouncedScriptSelection', () => {
         // act
         selection.processChanges({
           changes: [
-            { scriptId: script.id, newStatus: { isReverted: true, isSelected: true } },
+            { scriptId: script.executableId, newStatus: { isReverted: true, isSelected: true } },
           ],
         });
         debounceStub.execute();
@@ -525,7 +555,7 @@ describe('DebouncedScriptSelection', () => {
         for (const script of scripts) {
           selection.processChanges({
             changes: [
-              { scriptId: script.id, newStatus: { isReverted: true, isSelected: true } },
+              { scriptId: script.executableId, newStatus: { isReverted: true, isSelected: true } },
             ],
           });
         }
@@ -539,7 +569,7 @@ describe('DebouncedScriptSelection', () => {
 });
 
 function createCollectionWithScripts(...scripts: Script[]): CategoryCollectionStub {
-  const category = new CategoryStub(1).withScripts(...scripts);
+  const category = new CategoryStub('parent-category').withScripts(...scripts);
   const collection = new CategoryCollectionStub().withAction(category);
   return collection;
 }
@@ -572,7 +602,7 @@ function setupTestWithPreselectedScripts(options: {
     return initialSelection;
   })();
   const unselectedScripts = allScripts.filter(
-    (s) => !preselectedScripts.map((selected) => selected.id).includes(s.id),
+    (s) => !preselectedScripts.map((selected) => selected.id).includes(s.executableId),
   );
   const collection = createCollectionWithScripts(...allScripts);
   const scriptSelection = new DebouncedScriptSelectionBuilder()
diff --git a/tests/unit/application/Context/State/Selection/UserSelectionFacade.spec.ts b/tests/unit/application/Context/State/Selection/UserSelectionFacade.spec.ts
index 20c46b68..4bf6e05b 100644
--- a/tests/unit/application/Context/State/Selection/UserSelectionFacade.spec.ts
+++ b/tests/unit/application/Context/State/Selection/UserSelectionFacade.spec.ts
@@ -1,7 +1,7 @@
 import { describe, it } from 'vitest';
 import type { SelectedScript } from '@/application/Context/State/Selection/Script/SelectedScript';
 import { UserSelectionFacade } from '@/application/Context/State/Selection/UserSelectionFacade';
-import type { ICategoryCollection } from '@/domain/ICategoryCollection';
+import type { ICategoryCollection } from '@/domain/Collection/ICategoryCollection';
 import { CategoryCollectionStub } from '@tests/unit/shared/Stubs/CategoryCollectionStub';
 import type { ScriptsFactory, CategoriesFactory } from '@/application/Context/State/Selection/UserSelectionFacade';
 import { ScriptSelectionStub } from '@tests/unit/shared/Stubs/ScriptSelectionStub';
diff --git a/tests/unit/application/Parser/ApplicationParser.spec.ts b/tests/unit/application/Parser/ApplicationParser.spec.ts
index b3cb15d3..58bdbd07 100644
--- a/tests/unit/application/Parser/ApplicationParser.spec.ts
+++ b/tests/unit/application/Parser/ApplicationParser.spec.ts
@@ -14,7 +14,7 @@ import { ProjectDetailsStub } from '@tests/unit/shared/Stubs/ProjectDetailsStub'
 import type { CategoryCollectionParser } from '@/application/Parser/CategoryCollectionParser';
 import type { NonEmptyCollectionAssertion, TypeValidator } from '@/application/Parser/Common/TypeValidator';
 import { TypeValidatorStub } from '@tests/unit/shared/Stubs/TypeValidatorStub';
-import type { ICategoryCollection } from '@/domain/ICategoryCollection';
+import type { ICategoryCollection } from '@/domain/Collection/ICategoryCollection';
 
 describe('ApplicationParser', () => {
   describe('parseApplication', () => {
diff --git a/tests/unit/application/Parser/CategoryCollectionParser.spec.ts b/tests/unit/application/Parser/CategoryCollectionParser.spec.ts
index 0b311704..c27f7cd6 100644
--- a/tests/unit/application/Parser/CategoryCollectionParser.spec.ts
+++ b/tests/unit/application/Parser/CategoryCollectionParser.spec.ts
@@ -66,7 +66,10 @@ describe('CategoryCollectionParser', () => {
           getInitParameters,
         } = createCategoryCollectionFactorySpy();
         const actionsData = [getCategoryStub('test1'), getCategoryStub('test2')];
-        const expectedActions = [new CategoryStub(1), new CategoryStub(2)];
+        const expectedActions = [
+          new CategoryStub('expected-action-1'),
+          new CategoryStub('expected-action-2'),
+        ];
         const categoryParserStub = new CategoryParserStub()
           .withConfiguredParseResult(actionsData[0], expectedActions[0])
           .withConfiguredParseResult(actionsData[1], expectedActions[1]);
diff --git a/tests/unit/application/Parser/Executable/CategoryParser.spec.ts b/tests/unit/application/Parser/Executable/CategoryParser.spec.ts
index d6a9ba30..40a1642c 100644
--- a/tests/unit/application/Parser/Executable/CategoryParser.spec.ts
+++ b/tests/unit/application/Parser/Executable/CategoryParser.spec.ts
@@ -1,6 +1,6 @@
 import { describe, it, expect } from 'vitest';
 import type { CategoryData, ExecutableData } from '@/application/collections/';
-import { type CategoryFactory, parseCategory } from '@/application/Parser/Executable/CategoryParser';
+import { parseCategory } from '@/application/Parser/Executable/CategoryParser';
 import { type ScriptParser } from '@/application/Parser/Executable/Script/ScriptParser';
 import { type DocsParser } from '@/application/Parser/Executable/DocumentationParser';
 import { CategoryCollectionSpecificUtilitiesStub } from '@tests/unit/shared/Stubs/CategoryCollectionSpecificUtilitiesStub';
@@ -20,14 +20,48 @@ import { ScriptParserStub } from '@tests/unit/shared/Stubs/ScriptParserStub';
 import { formatAssertionMessage } from '@tests/shared/FormatAssertionMessage';
 import type { NonEmptyCollectionAssertion, ObjectAssertion } from '@/application/Parser/Common/TypeValidator';
 import { indentText } from '@/application/Common/Text/IndentText';
+import type { ExecutableId } from '@/domain/Executables/Identifiable';
+import type { CategoryFactory } from '@/domain/Executables/Category/CategoryFactory';
 import { itThrowsContextualError } from '../Common/ContextualErrorTester';
 import { itValidatesName, itValidatesType, itAsserts } from './Validation/ExecutableValidationTester';
 import { generateDataValidationTestScenarios } from './Validation/DataValidationTestScenarioGenerator';
 
 describe('CategoryParser', () => {
   describe('parseCategory', () => {
-    describe('validation', () => {
-      describe('validates for name', () => {
+    describe('id', () => {
+      it('creates ID correctly', () => {
+        // arrange
+        const expectedId: ExecutableId = 'expected-id';
+        const categoryData = new CategoryDataStub()
+          .withName(expectedId);
+        const { categoryFactorySpy, getInitParameters } = createCategoryFactorySpy();
+        // act
+        const actualScript = new TestContext()
+          .withData(categoryData)
+          .withCategoryFactory(categoryFactorySpy)
+          .parseCategory();
+        // assert
+        const actualId = getInitParameters(actualScript)?.executableId;
+        expect(actualId).to.equal(expectedId);
+      });
+    });
+    describe('name', () => {
+      it('parses name correctly', () => {
+        // arrange
+        const expectedName = 'test-expected-name';
+        const categoryData = new CategoryDataStub()
+          .withName(expectedName);
+        const { categoryFactorySpy, getInitParameters } = createCategoryFactorySpy();
+        // act
+        const actualCategory = new TestContext()
+          .withData(categoryData)
+          .withCategoryFactory(categoryFactorySpy)
+          .parseCategory();
+        // assert
+        const actualName = getInitParameters(actualCategory)?.name;
+        expect(actualName).to.equal(expectedName);
+      });
+      describe('validates name', () => {
         // arrange
         const expectedName = 'expected category name to be validated';
         const category = new CategoryDataStub()
@@ -38,7 +72,7 @@ describe('CategoryParser', () => {
         };
         itValidatesName((validatorFactory) => {
           // act
-          new TestBuilder()
+          new TestContext()
             .withData(category)
             .withValidatorFactory(validatorFactory)
             .parseCategory();
@@ -49,7 +83,33 @@ describe('CategoryParser', () => {
           };
         });
       });
-      describe('validates for unknown object', () => {
+    });
+    describe('docs', () => {
+      it('parses docs correctly', () => {
+        // arrange
+        const url = 'https://privacy.sexy';
+        const categoryData = new CategoryDataStub()
+          .withDocs(url);
+        const parseDocs: DocsParser = (data) => {
+          return [
+            `parsed docs: ${JSON.stringify(data)}`,
+          ];
+        };
+        const expectedDocs = parseDocs(categoryData);
+        const { categoryFactorySpy, getInitParameters } = createCategoryFactorySpy();
+        // act
+        const actualCategory = new TestContext()
+          .withData(categoryData)
+          .withCategoryFactory(categoryFactorySpy)
+          .withDocsParser(parseDocs)
+          .parseCategory();
+        // assert
+        const actualDocs = getInitParameters(actualCategory)?.docs;
+        expect(actualDocs).to.deep.equal(expectedDocs);
+      });
+    });
+    describe('property validation', () => {
+      describe('validates for unknown executable', () => {
         // arrange
         const category = new CategoryDataStub();
         const expectedContext: CategoryErrorContext = {
@@ -63,7 +123,7 @@ describe('CategoryParser', () => {
         itValidatesType(
           (validatorFactory) => {
             // act
-            new TestBuilder()
+            new TestContext()
               .withData(category)
               .withValidatorFactory(validatorFactory)
               .parseCategory();
@@ -90,7 +150,7 @@ describe('CategoryParser', () => {
         itValidatesType(
           (validatorFactory) => {
             // act
-            new TestBuilder()
+            new TestContext()
               .withData(category)
               .withValidatorFactory(validatorFactory)
               .parseCategory();
@@ -102,6 +162,8 @@ describe('CategoryParser', () => {
           },
         );
       });
+    });
+    describe('children', () => {
       describe('validates children for non-empty collection', () => {
         // arrange
         const category = new CategoryDataStub()
@@ -117,7 +179,7 @@ describe('CategoryParser', () => {
         itValidatesType(
           (validatorFactory) => {
             // act
-            new TestBuilder()
+            new TestContext()
               .withData(category)
               .withValidatorFactory(validatorFactory)
               .parseCategory();
@@ -167,7 +229,7 @@ describe('CategoryParser', () => {
                   parentCategory: parent,
                 };
                 // act
-                new TestBuilder()
+                new TestContext()
                   .withData(parent)
                   .withValidatorFactory(validatorFactory)
                   .parseCategory();
@@ -201,7 +263,7 @@ describe('CategoryParser', () => {
           itValidatesType(
             (validatorFactory) => {
               // act
-              new TestBuilder()
+              new TestContext()
                 .withData(parent)
                 .withValidatorFactory(validatorFactory)
                 .parseCategory();
@@ -231,7 +293,7 @@ describe('CategoryParser', () => {
           };
           itValidatesName((validatorFactory) => {
             // act
-            new TestBuilder()
+            new TestContext()
               .withData(parent)
               .withValidatorFactory(validatorFactory)
               .parseCategory();
@@ -243,178 +305,169 @@ describe('CategoryParser', () => {
           });
         });
       });
-    });
-    describe('rethrows exception if category factory fails', () => {
-      // arrange
-      const givenData = new CategoryDataStub();
-      const expectedContextMessage = 'Failed to parse category.';
-      const expectedError = new Error();
-      // act & assert
-      itThrowsContextualError({
-        throwingAction: (wrapError) => {
-          const validatorStub = new ExecutableValidatorStub();
-          validatorStub.createContextualErrorMessage = (message) => message;
-          const factoryMock: CategoryFactory = () => {
-            throw expectedError;
-          };
-          new TestBuilder()
-            .withCategoryFactory(factoryMock)
-            .withValidatorFactory(() => validatorStub)
-            .withErrorWrapper(wrapError)
-            .withData(givenData)
+      describe('parses correct subscript', () => {
+        it('parses single script correctly', () => {
+          // arrange
+          const expectedScript = new ScriptStub('expected script');
+          const scriptParser = new ScriptParserStub();
+          const childScriptData = createScriptDataWithCode();
+          const categoryData = new CategoryDataStub()
+            .withChildren([childScriptData]);
+          scriptParser.setupParsedResultForData(childScriptData, expectedScript);
+          const { categoryFactorySpy, getInitParameters } = createCategoryFactorySpy();
+          // act
+          const actualCategory = new TestContext()
+            .withData(categoryData)
+            .withScriptParser(scriptParser.get())
+            .withCategoryFactory(categoryFactorySpy)
             .parseCategory();
-        },
-        expectedWrappedError: expectedError,
-        expectedContextMessage,
+          // assert
+          const actualScripts = getInitParameters(actualCategory)?.scripts;
+          expectExists(actualScripts);
+          expect(actualScripts).to.have.lengthOf(1);
+          const actualScript = actualScripts[0];
+          expect(actualScript).to.equal(expectedScript);
+        });
+        it('parses multiple scripts correctly', () => {
+          // arrange
+          const expectedScripts = [
+            new ScriptStub('expected-first-script'),
+            new ScriptStub('expected-second-script'),
+          ];
+          const childrenData = [
+            createScriptDataWithCall(),
+            createScriptDataWithCode(),
+          ];
+          const scriptParser = new ScriptParserStub();
+          childrenData.forEach((_, index) => {
+            scriptParser.setupParsedResultForData(childrenData[index], expectedScripts[index]);
+          });
+          const categoryData = new CategoryDataStub()
+            .withChildren(childrenData);
+          const { categoryFactorySpy, getInitParameters } = createCategoryFactorySpy();
+          // act
+          const actualCategory = new TestContext()
+            .withScriptParser(scriptParser.get())
+            .withData(categoryData)
+            .withCategoryFactory(categoryFactorySpy)
+            .parseCategory();
+          // assert
+          const actualParsedScripts = getInitParameters(actualCategory)?.scripts;
+          expectExists(actualParsedScripts);
+          expect(actualParsedScripts.length).to.equal(expectedScripts.length);
+          expect(actualParsedScripts).to.have.members(expectedScripts);
+        });
+        it('parses all scripts with correct utilities', () => {
+          // arrange
+          const expected = new CategoryCollectionSpecificUtilitiesStub();
+          const scriptParser = new ScriptParserStub();
+          const childrenData = [
+            createScriptDataWithCode(),
+            createScriptDataWithCode(),
+            createScriptDataWithCode(),
+          ];
+          const categoryData = new CategoryDataStub()
+            .withChildren(childrenData);
+          const { categoryFactorySpy, getInitParameters } = createCategoryFactorySpy();
+          // act
+          const actualCategory = new TestContext()
+            .withData(categoryData)
+            .withCollectionUtilities(expected)
+            .withScriptParser(scriptParser.get())
+            .withCategoryFactory(categoryFactorySpy)
+            .parseCategory();
+          // assert
+          const actualParsedScripts = getInitParameters(actualCategory)?.scripts;
+          expectExists(actualParsedScripts);
+          const actualUtilities = actualParsedScripts.map(
+            (s) => scriptParser.getParseParameters(s)[1],
+          );
+          expect(
+            actualUtilities.every(
+              (actual) => actual === expected,
+            ),
+            formatAssertionMessage([
+              `Expected all elements to be ${JSON.stringify(expected)}`,
+              'All elements:',
+              indentText(JSON.stringify(actualUtilities)),
+            ]),
+          ).to.equal(true);
+        });
       });
-    });
-    it('parses docs correctly', () => {
-      // arrange
-      const url = 'https://privacy.sexy';
-      const categoryData = new CategoryDataStub()
-        .withDocs(url);
-      const parseDocs: DocsParser = (data) => {
-        return [
-          `parsed docs: ${JSON.stringify(data)}`,
-        ];
-      };
-      const expectedDocs = parseDocs(categoryData);
-      const { categoryFactorySpy, getInitParameters } = createCategoryFactorySpy();
-      // act
-      const actualCategory = new TestBuilder()
-        .withData(categoryData)
-        .withCategoryFactory(categoryFactorySpy)
-        .withDocsParser(parseDocs)
-        .parseCategory();
-      // assert
-      const actualDocs = getInitParameters(actualCategory)?.docs;
-      expect(actualDocs).to.deep.equal(expectedDocs);
-    });
-    describe('parses expected subscript', () => {
-      it('parses single script correctly', () => {
+      it('parses correct subcategories', () => {
         // arrange
-        const expectedScript = new ScriptStub('expected script');
-        const scriptParser = new ScriptParserStub();
-        const childScriptData = createScriptDataWithCode();
+        const expectedChildCategory = new CategoryStub('expected-child-category');
+        const childCategoryData = new CategoryDataStub()
+          .withName('expected child category')
+          .withChildren([createScriptDataWithCode()]);
         const categoryData = new CategoryDataStub()
-          .withChildren([childScriptData]);
-        scriptParser.setupParsedResultForData(childScriptData, expectedScript);
+          .withName('category name')
+          .withChildren([childCategoryData]);
         const { categoryFactorySpy, getInitParameters } = createCategoryFactorySpy();
         // act
-        const actualCategory = new TestBuilder()
+        const actualCategory = new TestContext()
           .withData(categoryData)
-          .withScriptParser(scriptParser.get())
-          .withCategoryFactory(categoryFactorySpy)
+          .withCategoryFactory((parameters) => {
+            if (parameters.name === childCategoryData.category) {
+              return expectedChildCategory;
+            }
+            return categoryFactorySpy(parameters);
+          })
           .parseCategory();
         // assert
-        const actualScripts = getInitParameters(actualCategory)?.scripts;
-        expectExists(actualScripts);
-        expect(actualScripts).to.have.lengthOf(1);
-        const actualScript = actualScripts[0];
-        expect(actualScript).to.equal(expectedScript);
+        const actualSubcategories = getInitParameters(actualCategory)?.subcategories;
+        expectExists(actualSubcategories);
+        expect(actualSubcategories).to.have.lengthOf(1);
+        expect(actualSubcategories[0]).to.equal(expectedChildCategory);
       });
-      it('parses multiple scripts correctly', () => {
+    });
+    describe('category creation', () => {
+      it('creates category from the factory', () => {
         // arrange
-        const expectedScripts = [
-          new ScriptStub('expected-first-script'),
-          new ScriptStub('expected-second-script'),
-        ];
-        const childrenData = [
-          createScriptDataWithCall(),
-          createScriptDataWithCode(),
-        ];
-        const scriptParser = new ScriptParserStub();
-        childrenData.forEach((_, index) => {
-          scriptParser.setupParsedResultForData(childrenData[index], expectedScripts[index]);
-        });
-        const categoryData = new CategoryDataStub()
-          .withChildren(childrenData);
-        const { categoryFactorySpy, getInitParameters } = createCategoryFactorySpy();
+        const expectedCategory = new CategoryStub('expected-category');
+        const categoryFactory: CategoryFactory = () => expectedCategory;
         // act
-        const actualCategory = new TestBuilder()
-          .withScriptParser(scriptParser.get())
-          .withData(categoryData)
-          .withCategoryFactory(categoryFactorySpy)
+        const actualCategory = new TestContext()
+          .withCategoryFactory(categoryFactory)
           .parseCategory();
         // assert
-        const actualParsedScripts = getInitParameters(actualCategory)?.scripts;
-        expectExists(actualParsedScripts);
-        expect(actualParsedScripts.length).to.equal(expectedScripts.length);
-        expect(actualParsedScripts).to.have.members(expectedScripts);
+        expect(actualCategory).to.equal(expectedCategory);
       });
-      it('parses all scripts with correct utilities', () => {
+      describe('rethrows exception if category factory fails', () => {
         // arrange
-        const expected = new CategoryCollectionSpecificUtilitiesStub();
-        const scriptParser = new ScriptParserStub();
-        const childrenData = [
-          createScriptDataWithCode(),
-          createScriptDataWithCode(),
-          createScriptDataWithCode(),
-        ];
-        const categoryData = new CategoryDataStub()
-          .withChildren(childrenData);
-        const { categoryFactorySpy, getInitParameters } = createCategoryFactorySpy();
-        // act
-        const actualCategory = new TestBuilder()
-          .withData(categoryData)
-          .withCollectionUtilities(expected)
-          .withScriptParser(scriptParser.get())
-          .withCategoryFactory(categoryFactorySpy)
-          .parseCategory();
-        // assert
-        const actualParsedScripts = getInitParameters(actualCategory)?.scripts;
-        expectExists(actualParsedScripts);
-        const actualUtilities = actualParsedScripts.map(
-          (s) => scriptParser.getParseParameters(s)[1],
-        );
-        expect(
-          actualUtilities.every(
-            (actual) => actual === expected,
-          ),
-          formatAssertionMessage([
-            `Expected all elements to be ${JSON.stringify(expected)}`,
-            'All elements:',
-            indentText(JSON.stringify(actualUtilities)),
-          ]),
-        ).to.equal(true);
+        const givenData = new CategoryDataStub();
+        const expectedContextMessage = 'Failed to parse category.';
+        const expectedError = new Error();
+        // act & assert
+        itThrowsContextualError({
+          throwingAction: (wrapError) => {
+            const validatorStub = new ExecutableValidatorStub();
+            validatorStub.createContextualErrorMessage = (message) => message;
+            const factoryMock: CategoryFactory = () => {
+              throw expectedError;
+            };
+            new TestContext()
+              .withCategoryFactory(factoryMock)
+              .withValidatorFactory(() => validatorStub)
+              .withErrorWrapper(wrapError)
+              .withData(givenData)
+              .parseCategory();
+          },
+          expectedWrappedError: expectedError,
+          expectedContextMessage,
+        });
       });
     });
-    it('returns expected subcategories', () => {
-      // arrange
-      const expectedChildCategory = new CategoryStub(33);
-      const childCategoryData = new CategoryDataStub()
-        .withName('expected child category')
-        .withChildren([createScriptDataWithCode()]);
-      const categoryData = new CategoryDataStub()
-        .withName('category name')
-        .withChildren([childCategoryData]);
-      const { categoryFactorySpy, getInitParameters } = createCategoryFactorySpy();
-      // act
-      const actualCategory = new TestBuilder()
-        .withData(categoryData)
-        .withCategoryFactory((parameters) => {
-          if (parameters.name === childCategoryData.category) {
-            return expectedChildCategory;
-          }
-          return categoryFactorySpy(parameters);
-        })
-        .parseCategory();
-      // assert
-      const actualSubcategories = getInitParameters(actualCategory)?.subcategories;
-      expectExists(actualSubcategories);
-      expect(actualSubcategories).to.have.lengthOf(1);
-      expect(actualSubcategories[0]).to.equal(expectedChildCategory);
-    });
   });
 });
 
-class TestBuilder {
+class TestContext {
   private data: CategoryData = new CategoryDataStub();
 
   private collectionUtilities:
   CategoryCollectionSpecificUtilitiesStub = new CategoryCollectionSpecificUtilitiesStub();
 
-  private categoryFactory: CategoryFactory = () => new CategoryStub(33);
+  private categoryFactory: CategoryFactory = createCategoryFactorySpy().categoryFactorySpy;
 
   private errorWrapper: ErrorWithContextWrapper = new ErrorWrapperStub().get();
 
diff --git a/tests/unit/application/Parser/Executable/Script/ScriptParser.spec.ts b/tests/unit/application/Parser/Executable/Script/ScriptParser.spec.ts
index de27f5b2..74b034c7 100644
--- a/tests/unit/application/Parser/Executable/Script/ScriptParser.spec.ts
+++ b/tests/unit/application/Parser/Executable/Script/ScriptParser.spec.ts
@@ -1,6 +1,6 @@
 import { describe, it, expect } from 'vitest';
 import type { ScriptData, CallScriptData, CodeScriptData } from '@/application/collections/';
-import { parseScript, type ScriptFactory } from '@/application/Parser/Executable/Script/ScriptParser';
+import { parseScript } from '@/application/Parser/Executable/Script/ScriptParser';
 import { type DocsParser } from '@/application/Parser/Executable/DocumentationParser';
 import { RecommendationLevel } from '@/domain/Executables/Script/RecommendationLevel';
 import { itEachAbsentStringValue } from '@tests/unit/shared/TestCases/AbsentTests';
@@ -29,53 +29,207 @@ import { itThrowsContextualError } from '@tests/unit/application/Parser/Common/C
 import { CategoryCollectionSpecificUtilitiesStub } from '@tests/unit/shared/Stubs/CategoryCollectionSpecificUtilitiesStub';
 import type { CategoryCollectionSpecificUtilities } from '@/application/Parser/Executable/CategoryCollectionSpecificUtilities';
 import type { ObjectAssertion } from '@/application/Parser/Common/TypeValidator';
+import type { ExecutableId } from '@/domain/Executables/Identifiable';
+import type { ScriptFactory } from '@/domain/Executables/Script/ScriptFactory';
 import { itAsserts, itValidatesType, itValidatesName } from '../Validation/ExecutableValidationTester';
 import { generateDataValidationTestScenarios } from '../Validation/DataValidationTestScenarioGenerator';
 
 describe('ScriptParser', () => {
   describe('parseScript', () => {
-    it('parses name correctly', () => {
-      // arrange
-      const expected = 'test-expected-name';
-      const scriptData = createScriptDataWithCode()
-        .withName(expected);
-      const { scriptFactorySpy, getInitParameters } = createScriptFactorySpy();
-      // act
-      const actualScript = new TestContext()
-        .withData(scriptData)
-        .withScriptFactory(scriptFactorySpy)
-        .parseScript();
-      // assert
-      const actualName = getInitParameters(actualScript)?.name;
-      expect(actualName).to.equal(expected);
+    describe('property validation', () => {
+      describe('validates object', () => {
+        // arrange
+        const expectedScript = createScriptDataWithCall();
+        const expectedContext: ScriptErrorContext = {
+          type: ExecutableType.Script,
+          self: expectedScript,
+        };
+        const expectedAssertion: ObjectAssertion<CallScriptData & CodeScriptData> = {
+          value: expectedScript,
+          valueName: expectedScript.name,
+          allowedProperties: [
+            'name', 'recommend', 'code', 'revertCode', 'call', 'docs',
+          ],
+        };
+        itValidatesType(
+          (validatorFactory) => {
+            // act
+            new TestContext()
+              .withData(expectedScript)
+              .withValidatorFactory(validatorFactory)
+              .parseScript();
+            // assert
+            return {
+              expectedDataToValidate: expectedScript,
+              expectedErrorContext: expectedContext,
+              assertValidation: (validator) => validator.assertObject(expectedAssertion),
+            };
+          },
+        );
+      });
+      describe('validates union type', () => {
+        // arrange
+        const testScenarios = generateDataValidationTestScenarios<ScriptData>(
+          {
+            assertErrorMessage: 'Neither "call" or "code" is defined.',
+            expectFail: [{
+              description: 'with no call or code',
+              data: createScriptDataWithoutCallOrCodes(),
+            }],
+            expectPass: [
+              {
+                description: 'with call',
+                data: createScriptDataWithCall(),
+              },
+              {
+                description: 'with code',
+                data: createScriptDataWithCode(),
+              },
+            ],
+          },
+          {
+            assertErrorMessage: 'Both "call" and "revertCode" are defined.',
+            expectFail: [{
+              description: 'with both call and revertCode',
+              data: createScriptDataWithCall()
+                .withRevertCode('revert-code'),
+            }],
+            expectPass: [
+              {
+                description: 'with call, without revertCode',
+                data: createScriptDataWithCall()
+                  .withRevertCode(undefined),
+              },
+              {
+                description: 'with revertCode, without call',
+                data: createScriptDataWithCode()
+                  .withRevertCode('revert code'),
+              },
+            ],
+          },
+          {
+            assertErrorMessage: 'Both "call" and "code" are defined.',
+            expectFail: [{
+              description: 'with both call and code',
+              data: createScriptDataWithCall()
+                .withCode('code'),
+            }],
+            expectPass: [
+              {
+                description: 'with call, without code',
+                data: createScriptDataWithCall()
+                  .withCode(''),
+              },
+              {
+                description: 'with code, without call',
+                data: createScriptDataWithCode()
+                  .withCode('code'),
+              },
+            ],
+          },
+        );
+        testScenarios.forEach(({
+          description, expectedPass, data: scriptData, expectedMessage,
+        }) => {
+          describe(description, () => {
+            itAsserts({
+              expectedConditionResult: expectedPass,
+              test: (validatorFactory) => {
+                const expectedContext: ScriptErrorContext = {
+                  type: ExecutableType.Script,
+                  self: scriptData,
+                };
+                // act
+                new TestContext()
+                  .withData(scriptData)
+                  .withValidatorFactory(validatorFactory)
+                  .parseScript();
+                // assert
+                expectExists(expectedMessage);
+                return {
+                  expectedErrorMessage: expectedMessage,
+                  expectedErrorContext: expectedContext,
+                };
+              },
+            });
+          });
+        });
+      });
     });
-    it('parses docs correctly', () => {
-      // arrange
-      const expectedDocs = ['https://expected-doc1.com', 'https://expected-doc2.com'];
-      const { scriptFactorySpy, getInitParameters } = createScriptFactorySpy();
-      const scriptData = createScriptDataWithCode()
-        .withDocs(expectedDocs);
-      const docsParser: DocsParser = (data) => data.docs as typeof expectedDocs;
-      // act
-      const actualScript = new TestContext()
-        .withData(scriptData)
-        .withScriptFactory(scriptFactorySpy)
-        .withDocsParser(docsParser)
-        .parseScript();
-      // assert
-      const actualDocs = getInitParameters(actualScript)?.docs;
-      expect(actualDocs).to.deep.equal(expectedDocs);
+    describe('id', () => {
+      it('creates ID correctly', () => {
+        // arrange
+        const expectedId: ExecutableId = 'expected-id';
+        const scriptData = createScriptDataWithCode()
+          .withName(expectedId);
+        const { scriptFactorySpy, getInitParameters } = createScriptFactorySpy();
+        // act
+        const actualScript = new TestContext()
+          .withData(scriptData)
+          .withScriptFactory(scriptFactorySpy)
+          .parseScript();
+        // assert
+        const actualId = getInitParameters(actualScript)?.executableId;
+        expect(actualId).to.equal(expectedId);
+      });
+    });
+    describe('name', () => {
+      it('parses name correctly', () => {
+        // arrange
+        const expected = 'test-expected-name';
+        const scriptData = createScriptDataWithCode()
+          .withName(expected);
+        const { scriptFactorySpy, getInitParameters } = createScriptFactorySpy();
+        // act
+        const actualScript = new TestContext()
+          .withData(scriptData)
+          .withScriptFactory(scriptFactorySpy)
+          .parseScript();
+        // assert
+        const actualName = getInitParameters(actualScript)?.name;
+        expect(actualName).to.equal(expected);
+      });
+      describe('validates name', () => {
+        // arrange
+        const expectedName = 'expected script name to be validated';
+        const script = createScriptDataWithCall()
+          .withName(expectedName);
+        const expectedContext: ScriptErrorContext = {
+          type: ExecutableType.Script,
+          self: script,
+        };
+        itValidatesName((validatorFactory) => {
+          // act
+          new TestContext()
+            .withData(script)
+            .withValidatorFactory(validatorFactory)
+            .parseScript();
+          // assert
+          return {
+            expectedNameToValidate: expectedName,
+            expectedErrorContext: expectedContext,
+          };
+        });
+      });
     });
-    it('gets script from the factory', () => {
-      // arrange
-      const expectedScript = new ScriptStub('expected-script');
-      const scriptFactory: ScriptFactory = () => expectedScript;
-      // act
-      const actualScript = new TestContext()
-        .withScriptFactory(scriptFactory)
-        .parseScript();
-      // assert
-      expect(actualScript).to.equal(expectedScript);
+    describe('docs', () => {
+      it('parses docs correctly', () => {
+        // arrange
+        const expectedDocs = ['https://expected-doc1.com', 'https://expected-doc2.com'];
+        const { scriptFactorySpy, getInitParameters } = createScriptFactorySpy();
+        const scriptData = createScriptDataWithCode()
+          .withDocs(expectedDocs);
+        const docsParser: DocsParser = (data) => data.docs as typeof expectedDocs;
+        // act
+        const actualScript = new TestContext()
+          .withData(scriptData)
+          .withScriptFactory(scriptFactorySpy)
+          .withDocsParser(docsParser)
+          .parseScript();
+        // assert
+        const actualDocs = getInitParameters(actualScript)?.docs;
+        expect(actualDocs).to.deep.equal(expectedDocs);
+      });
     });
     describe('level', () => {
       describe('generated `undefined` level if given absent value', () => {
@@ -261,175 +415,46 @@ describe('ScriptParser', () => {
         });
       });
     });
-    describe('validation', () => {
-      describe('validates for name', () => {
+    describe('script creation', () => {
+      it('creates script from the factory', () => {
         // arrange
-        const expectedName = 'expected script name to be validated';
-        const script = createScriptDataWithCall()
-          .withName(expectedName);
-        const expectedContext: ScriptErrorContext = {
-          type: ExecutableType.Script,
-          self: script,
-        };
-        itValidatesName((validatorFactory) => {
-          // act
-          new TestContext()
-            .withData(script)
-            .withValidatorFactory(validatorFactory)
-            .parseScript();
-          // assert
-          return {
-            expectedNameToValidate: expectedName,
-            expectedErrorContext: expectedContext,
-          };
-        });
+        const expectedScript = new ScriptStub('expected-script');
+        const scriptFactory: ScriptFactory = () => expectedScript;
+        // act
+        const actualScript = new TestContext()
+          .withScriptFactory(scriptFactory)
+          .parseScript();
+        // assert
+        expect(actualScript).to.equal(expectedScript);
       });
-      describe('validates for defined data', () => {
+      describe('rethrows exception if script factory fails', () => {
         // arrange
-        const expectedScript = createScriptDataWithCall();
-        const expectedContext: ScriptErrorContext = {
-          type: ExecutableType.Script,
-          self: expectedScript,
-        };
-        const expectedAssertion: ObjectAssertion<CallScriptData & CodeScriptData> = {
-          value: expectedScript,
-          valueName: expectedScript.name,
-          allowedProperties: [
-            'name', 'recommend', 'code', 'revertCode', 'call', 'docs',
-          ],
+        const givenData = createScriptDataWithCode();
+        const expectedContextMessage = 'Failed to parse script.';
+        const expectedError = new Error();
+        const validatorFactory: ExecutableValidatorFactory = () => {
+          const validatorStub = new ExecutableValidatorStub();
+          validatorStub.createContextualErrorMessage = (message) => message;
+          return validatorStub;
         };
-        itValidatesType(
-          (validatorFactory) => {
-            // act
+        // act & assert
+        itThrowsContextualError({
+          throwingAction: (wrapError) => {
+            const factoryMock: ScriptFactory = () => {
+              throw expectedError;
+            };
             new TestContext()
-              .withData(expectedScript)
+              .withScriptFactory(factoryMock)
+              .withErrorWrapper(wrapError)
               .withValidatorFactory(validatorFactory)
+              .withData(givenData)
               .parseScript();
-            // assert
-            return {
-              expectedDataToValidate: expectedScript,
-              expectedErrorContext: expectedContext,
-              assertValidation: (validator) => validator.assertObject(expectedAssertion),
-            };
           },
-        );
-      });
-      describe('validates data', () => {
-        // arrange
-        const testScenarios = generateDataValidationTestScenarios<ScriptData>(
-          {
-            assertErrorMessage: 'Neither "call" or "code" is defined.',
-            expectFail: [{
-              description: 'with no call or code',
-              data: createScriptDataWithoutCallOrCodes(),
-            }],
-            expectPass: [
-              {
-                description: 'with call',
-                data: createScriptDataWithCall(),
-              },
-              {
-                description: 'with code',
-                data: createScriptDataWithCode(),
-              },
-            ],
-          },
-          {
-            assertErrorMessage: 'Both "call" and "revertCode" are defined.',
-            expectFail: [{
-              description: 'with both call and revertCode',
-              data: createScriptDataWithCall()
-                .withRevertCode('revert-code'),
-            }],
-            expectPass: [
-              {
-                description: 'with call, without revertCode',
-                data: createScriptDataWithCall()
-                  .withRevertCode(undefined),
-              },
-              {
-                description: 'with revertCode, without call',
-                data: createScriptDataWithCode()
-                  .withRevertCode('revert code'),
-              },
-            ],
-          },
-          {
-            assertErrorMessage: 'Both "call" and "code" are defined.',
-            expectFail: [{
-              description: 'with both call and code',
-              data: createScriptDataWithCall()
-                .withCode('code'),
-            }],
-            expectPass: [
-              {
-                description: 'with call, without code',
-                data: createScriptDataWithCall()
-                  .withCode(''),
-              },
-              {
-                description: 'with code, without call',
-                data: createScriptDataWithCode()
-                  .withCode('code'),
-              },
-            ],
-          },
-        );
-        testScenarios.forEach(({
-          description, expectedPass, data: scriptData, expectedMessage,
-        }) => {
-          describe(description, () => {
-            itAsserts({
-              expectedConditionResult: expectedPass,
-              test: (validatorFactory) => {
-                const expectedContext: ScriptErrorContext = {
-                  type: ExecutableType.Script,
-                  self: scriptData,
-                };
-                // act
-                new TestContext()
-                  .withData(scriptData)
-                  .withValidatorFactory(validatorFactory)
-                  .parseScript();
-                // assert
-                expectExists(expectedMessage);
-                return {
-                  expectedErrorMessage: expectedMessage,
-                  expectedErrorContext: expectedContext,
-                };
-              },
-            });
-          });
+          expectedWrappedError: expectedError,
+          expectedContextMessage,
         });
       });
     });
-    describe('rethrows exception if script factory fails', () => {
-      // arrange
-      const givenData = createScriptDataWithCode();
-      const expectedContextMessage = 'Failed to parse script.';
-      const expectedError = new Error();
-      const validatorFactory: ExecutableValidatorFactory = () => {
-        const validatorStub = new ExecutableValidatorStub();
-        validatorStub.createContextualErrorMessage = (message) => message;
-        return validatorStub;
-      };
-      // act & assert
-      itThrowsContextualError({
-        throwingAction: (wrapError) => {
-          const factoryMock: ScriptFactory = () => {
-            throw expectedError;
-          };
-          new TestContext()
-            .withScriptFactory(factoryMock)
-            .withErrorWrapper(wrapError)
-            .withValidatorFactory(validatorFactory)
-            .withData(givenData)
-            .parseScript();
-        },
-        expectedWrappedError: expectedError,
-        expectedContextMessage,
-      });
-    });
   });
 });
 
diff --git a/tests/unit/domain/Application.spec.ts b/tests/unit/domain/Application.spec.ts
index 29f44610..a408a6b8 100644
--- a/tests/unit/domain/Application.spec.ts
+++ b/tests/unit/domain/Application.spec.ts
@@ -3,7 +3,7 @@ import { Application } from '@/domain/Application';
 import { OperatingSystem } from '@/domain/OperatingSystem';
 import { CategoryCollectionStub } from '@tests/unit/shared/Stubs/CategoryCollectionStub';
 import { ProjectDetailsStub } from '@tests/unit/shared/Stubs/ProjectDetailsStub';
-import type { ICategoryCollection } from '@/domain/ICategoryCollection';
+import type { ICategoryCollection } from '@/domain/Collection/ICategoryCollection';
 import { getAbsentCollectionTestCases } from '@tests/unit/shared/TestCases/AbsentTests';
 
 describe('Application', () => {
diff --git a/tests/unit/domain/CategoryCollection.spec.ts b/tests/unit/domain/Collection/CategoryCollection.spec.ts
similarity index 57%
rename from tests/unit/domain/CategoryCollection.spec.ts
rename to tests/unit/domain/Collection/CategoryCollection.spec.ts
index b19d2fa5..e7310732 100644
--- a/tests/unit/domain/CategoryCollection.spec.ts
+++ b/tests/unit/domain/Collection/CategoryCollection.spec.ts
@@ -5,7 +5,7 @@ import type { IScriptingDefinition } from '@/domain/IScriptingDefinition';
 import { ScriptingLanguage } from '@/domain/ScriptingLanguage';
 import { RecommendationLevel } from '@/domain/Executables/Script/RecommendationLevel';
 import { getEnumValues } from '@/application/Common/Enum';
-import { CategoryCollection } from '@/domain/CategoryCollection';
+import { CategoryCollection } from '@/domain/Collection/CategoryCollection';
 import { ScriptStub } from '@tests/unit/shared/Stubs/ScriptStub';
 import { CategoryStub } from '@tests/unit/shared/Stubs/CategoryStub';
 import { EnumRangeTestRunner } from '@tests/unit/application/Common/EnumRangeTestRunner';
@@ -20,10 +20,10 @@ describe('CategoryCollection', () => {
       );
       const toIgnore = new ScriptStub('script-to-ignore').withLevel(undefined);
       for (const currentLevel of recommendationLevels) {
-        const category = new CategoryStub(0)
+        const category = new CategoryStub('parent-action')
           .withScripts(...scriptsWithLevels)
           .withScript(toIgnore);
-        const sut = new CategoryCollectionBuilder()
+        const sut = new TestContext()
           .withActions([category])
           .construct();
         // act
@@ -40,12 +40,12 @@ describe('CategoryCollection', () => {
         new ScriptStub('S2').withLevel(level),
       ];
       const actions = [
-        new CategoryStub(3).withScripts(
+        new CategoryStub('parent-category').withScripts(
           ...expected,
           new ScriptStub('S3').withLevel(RecommendationLevel.Strict),
         ),
       ];
-      const sut = new CategoryCollectionBuilder()
+      const sut = new TestContext()
         .withActions(actions)
         .construct();
       // act
@@ -61,9 +61,9 @@ describe('CategoryCollection', () => {
         new ScriptStub('S2').withLevel(RecommendationLevel.Strict),
       ];
       const actions = [
-        new CategoryStub(3).withScripts(...expected),
+        new CategoryStub('parent-category').withScripts(...expected),
       ];
-      const sut = new CategoryCollectionBuilder()
+      const sut = new TestContext()
         .withActions(actions)
         .construct();
       // act
@@ -74,7 +74,7 @@ describe('CategoryCollection', () => {
     describe('throws when given invalid level', () => {
       new EnumRangeTestRunner<RecommendationLevel>((level) => {
         // arrange
-        const sut = new CategoryCollectionBuilder()
+        const sut = new TestContext()
           .construct();
         // act
         sut.getScriptsByLevel(level);
@@ -84,93 +84,23 @@ describe('CategoryCollection', () => {
         .testValidValueDoesNotThrow(RecommendationLevel.Standard);
     });
   });
-  describe('actions', () => {
-    it('cannot construct without actions', () => {
-      // arrange
-      const categories = [];
-      // act
-      function construct() {
-        new CategoryCollectionBuilder()
-          .withActions(categories)
-          .construct();
-      }
-      // assert
-      expect(construct).to.throw('must consist of at least one category');
-    });
-    it('cannot construct without scripts', () => {
-      // arrange
-      const categories = [
-        new CategoryStub(3),
-        new CategoryStub(2),
-      ];
-      // act
-      function construct() {
-        new CategoryCollectionBuilder()
-          .withActions(categories)
-          .construct();
-      }
-      // assert
-      expect(construct).to.throw('must consist of at least one script');
-    });
-    describe('cannot construct without any recommended scripts', () => {
-      describe('single missing', () => {
-        // arrange
-        const recommendationLevels = getEnumValues(RecommendationLevel);
-        for (const missingLevel of recommendationLevels) {
-          it(`when "${RecommendationLevel[missingLevel]}" is missing`, () => {
-            const expectedError = `none of the scripts are recommended as "${RecommendationLevel[missingLevel]}".`;
-            const otherLevels = recommendationLevels.filter((level) => level !== missingLevel);
-            const categories = otherLevels.map(
-              (level, index) => new CategoryStub(index)
-                .withScript(
-                  new ScriptStub(`Script${index}`).withLevel(level),
-                ),
-            );
-            // act
-            const construct = () => new CategoryCollectionBuilder()
-              .withActions(categories)
-              .construct();
-            // assert
-            expect(construct).to.throw(expectedError);
-          });
-        }
-      });
-      it('multiple are missing', () => {
-        // arrange
-        const expectedError = 'none of the scripts are recommended as '
-          + `"${RecommendationLevel[RecommendationLevel.Standard]}, "${RecommendationLevel[RecommendationLevel.Strict]}".`;
-        const categories = [
-          new CategoryStub(0)
-            .withScript(
-              new ScriptStub(`Script${0}`).withLevel(undefined),
-            ),
-        ];
-        // act
-        const construct = () => new CategoryCollectionBuilder()
-          .withActions(categories)
-          .construct();
-        // assert
-        expect(construct).to.throw(expectedError);
-      });
-    });
-  });
   describe('totalScripts', () => {
     it('returns total of initial scripts', () => {
       // arrange
       const categories = [
-        new CategoryStub(1).withScripts(
+        new CategoryStub('category-1').withScripts(
           new ScriptStub('S1').withLevel(RecommendationLevel.Standard),
         ),
-        new CategoryStub(2).withScripts(
+        new CategoryStub('category-2').withScripts(
           new ScriptStub('S2'),
           new ScriptStub('S3').withLevel(RecommendationLevel.Strict),
         ),
-        new CategoryStub(3).withCategories(
-          new CategoryStub(4).withScripts(new ScriptStub('S4')),
+        new CategoryStub('category-3').withCategories(
+          new CategoryStub('category-3-subcategory-1').withScripts(new ScriptStub('S4')),
         ),
       ];
       // act
-      const sut = new CategoryCollectionBuilder()
+      const sut = new TestContext()
         .withActions(categories)
         .construct();
       // assert
@@ -182,12 +112,12 @@ describe('CategoryCollection', () => {
       // arrange
       const expected = 4;
       const categories = [
-        new CategoryStub(1).withScripts(new ScriptStub('S1').withLevel(RecommendationLevel.Strict)),
-        new CategoryStub(2).withScripts(new ScriptStub('S2'), new ScriptStub('S3')),
-        new CategoryStub(3).withCategories(new CategoryStub(4).withScripts(new ScriptStub('S4'))),
+        new CategoryStub('category-1').withScripts(new ScriptStub('S1').withLevel(RecommendationLevel.Strict)),
+        new CategoryStub('category-2').withScripts(new ScriptStub('S2'), new ScriptStub('S3')),
+        new CategoryStub('category-3').withCategories(new CategoryStub('category-3-subcategory-1').withScripts(new ScriptStub('S4'))),
       ];
       // act
-      const sut = new CategoryCollectionBuilder()
+      const sut = new TestContext()
         .withActions(categories)
         .construct();
       // assert
@@ -199,28 +129,19 @@ describe('CategoryCollection', () => {
       // arrange
       const expected = OperatingSystem.macOS;
       // act
-      const sut = new CategoryCollectionBuilder()
+      const sut = new TestContext()
         .withOs(expected)
         .construct();
       // assert
       expect(sut.os).to.deep.equal(expected);
     });
-    describe('throws when invalid', () => {
-      // act
-      const act = (os: OperatingSystem) => new CategoryCollectionBuilder()
-        .withOs(os)
-        .construct();
-      // assert
-      new EnumRangeTestRunner(act)
-        .testOutOfRangeThrows();
-    });
   });
   describe('scriptingDefinition', () => {
     it('sets scriptingDefinition as expected', () => {
       // arrange
       const expected = getValidScriptingDefinition();
       // act
-      const sut = new CategoryCollectionBuilder()
+      const sut = new TestContext()
         .withScripting(expected)
         .construct();
       // assert
@@ -230,25 +151,25 @@ describe('CategoryCollection', () => {
   describe('getCategory', () => {
     it('throws if category is not found', () => {
       // arrange
-      const categoryId = 123;
-      const expectedError = `Missing category with ID: "${categoryId}"`;
-      const collection = new CategoryCollectionBuilder()
-        .withActions([new CategoryStub(456).withMandatoryScripts()])
+      const missingCategoryId = 'missing-category-id';
+      const expectedError = `Missing category with ID: "${missingCategoryId}"`;
+      const collection = new TestContext()
+        .withActions([new CategoryStub(`different than ${missingCategoryId}`).withMandatoryScripts()])
         .construct();
       // act
-      const act = () => collection.getCategory(categoryId);
+      const act = () => collection.getCategory(missingCategoryId);
       // assert
       expect(act).to.throw(expectedError);
     });
     it('finds correct category', () => {
       // arrange
-      const categoryId = 123;
-      const expectedCategory = new CategoryStub(categoryId).withMandatoryScripts();
-      const collection = new CategoryCollectionBuilder()
+      const existingCategoryId = 'expected-action-category-id';
+      const expectedCategory = new CategoryStub(existingCategoryId).withMandatoryScripts();
+      const collection = new TestContext()
         .withActions([expectedCategory])
         .construct();
       // act
-      const actualCategory = collection.getCategory(categoryId);
+      const actualCategory = collection.getCategory(existingCategoryId);
       // assert
       expect(actualCategory).to.equal(expectedCategory);
     });
@@ -257,9 +178,9 @@ describe('CategoryCollection', () => {
     it('throws if script is not found', () => {
       // arrange
       const scriptId = 'missingScript';
-      const expectedError = `missing script: ${scriptId}`;
-      const collection = new CategoryCollectionBuilder()
-        .withActions([new CategoryStub(456).withMandatoryScripts()])
+      const expectedError = `Missing script: ${scriptId}`;
+      const collection = new TestContext()
+        .withActions([new CategoryStub('parent-action').withMandatoryScripts()])
         .construct();
       // act
       const act = () => collection.getScript(scriptId);
@@ -270,10 +191,10 @@ describe('CategoryCollection', () => {
       // arrange
       const scriptId = 'existingScript';
       const expectedScript = new ScriptStub(scriptId);
-      const parentCategory = new CategoryStub(123)
+      const parentCategory = new CategoryStub('parent-action')
         .withMandatoryScripts()
         .withScript(expectedScript);
-      const collection = new CategoryCollectionBuilder()
+      const collection = new TestContext()
         .withActions([parentCategory])
         .construct();
       // act
@@ -293,11 +214,11 @@ function getValidScriptingDefinition(): IScriptingDefinition {
   };
 }
 
-class CategoryCollectionBuilder {
+class TestContext {
   private os = OperatingSystem.Windows;
 
   private actions: readonly Category[] = [
-    new CategoryStub(1).withMandatoryScripts(),
+    new CategoryStub(`[${TestContext.name}]-action-1`).withMandatoryScripts(),
   ];
 
   private scriptingDefinition: IScriptingDefinition = getValidScriptingDefinition();
diff --git a/tests/unit/domain/Collection/Validation/CompositeCategoryCollectionValidator.spec.ts b/tests/unit/domain/Collection/Validation/CompositeCategoryCollectionValidator.spec.ts
new file mode 100644
index 00000000..2250c28a
--- /dev/null
+++ b/tests/unit/domain/Collection/Validation/CompositeCategoryCollectionValidator.spec.ts
@@ -0,0 +1,170 @@
+import { describe, it, expect } from 'vitest';
+import { validateCategoryCollection } from '@/domain/Collection/Validation/CompositeCategoryCollectionValidator';
+import type { CategoryCollectionValidationContext, CategoryCollectionValidator } from '@/domain/Collection/Validation/CategoryCollectionValidator';
+import { CategoryCollectionValidationContextStub } from '@tests/unit/shared/Stubs/CategoryCollectionValidationContextStub';
+
+describe('validateCategoryCollection', () => {
+  it('throws error when no validators are provided', () => {
+    // arrange
+    const emptyValidators: CategoryCollectionValidator[] = [];
+    const expectedErrorMessage = 'No validators provided.';
+
+    // act
+    const act = () => new TestContext()
+      .withValidators(emptyValidators)
+      .runValidation();
+
+    // assert
+    expect(act).to.throw(expectedErrorMessage);
+  });
+
+  describe('validator execution', () => {
+    it('executes single validator', () => {
+      // arrange
+      let isCalled = false;
+      const singleValidator: CategoryCollectionValidator = () => {
+        isCalled = true;
+      };
+      const validators = [singleValidator];
+
+      // act
+      new TestContext()
+        .withValidators(validators)
+        .runValidation();
+
+      // assert
+      expect(isCalled).to.equal(true);
+    });
+
+    it('executes multiple validators in order', () => {
+      // arrange
+      const expectedExecutionSequence: readonly string[] = [
+        'validator1Call',
+        'validator2Call',
+      ];
+      const actualExecutionSequence: string[] = [];
+      const validator1: CategoryCollectionValidator = () => {
+        actualExecutionSequence.push(expectedExecutionSequence[0]);
+      };
+      const validator2: CategoryCollectionValidator = () => {
+        actualExecutionSequence.push(expectedExecutionSequence[1]);
+      };
+      const validators = [validator1, validator2];
+
+      // act
+      new TestContext()
+        .withValidators(validators)
+        .runValidation();
+
+      // assert
+      expect(actualExecutionSequence).to.deep.equal(expectedExecutionSequence);
+    });
+
+    it('passes correct context to single validator', () => {
+      // arrange
+      const expectedContext = new CategoryCollectionValidationContextStub();
+      let actualContext: CategoryCollectionValidationContext | undefined;
+      const validator: CategoryCollectionValidator = (context) => {
+        actualContext = context;
+      };
+      const validators = [validator];
+
+      // act
+      new TestContext()
+        .withValidators(validators)
+        .withValidationContext(expectedContext)
+        .runValidation();
+
+      // assert
+      expect(expectedContext).to.equal(actualContext);
+    });
+
+    it('passes same context to all validators', () => {
+      // arrange
+      const expectedContext = new CategoryCollectionValidationContextStub();
+      const receivedContexts = new Array<CategoryCollectionValidationContext>();
+      const contextStoringValidator: CategoryCollectionValidator = (context) => {
+        receivedContexts.push(context);
+      };
+      const validators = [
+        contextStoringValidator,
+        contextStoringValidator,
+        contextStoringValidator,
+      ];
+
+      // act
+      new TestContext()
+        .withValidators(validators)
+        .withValidationContext(expectedContext)
+        .runValidation();
+
+      // assert
+      expect(receivedContexts.every((c) => c === expectedContext)).to.equal(true);
+    });
+  });
+
+  it('propagates error from validator', () => {
+    // arrange
+    const expectedError = 'Error from validator';
+    const errorThrowingValidator: CategoryCollectionValidator = () => {
+      throw new Error(expectedError);
+    };
+    const validators = [errorThrowingValidator];
+
+    // act
+    const act = () => new TestContext()
+      .withValidators(validators)
+      .runValidation();
+
+    // Act & Assert
+    expect(act).to.throw(expectedError);
+  });
+
+  it('halts execution on validator error', () => {
+    // arrange
+    const errorThrowingValidator: CategoryCollectionValidator = () => {
+      throw new Error('Error from validator');
+    };
+    let isSecondValidatorCalled = false;
+    const secondValidator: CategoryCollectionValidator = () => {
+      isSecondValidatorCalled = true;
+    };
+    const validators = [errorThrowingValidator, secondValidator];
+
+    // act
+    try {
+      new TestContext()
+        .withValidators(validators)
+        .runValidation();
+    } catch { /* Swallow */ }
+
+    // Act & Assert
+    expect(isSecondValidatorCalled).to.equal(false);
+  });
+});
+
+class TestContext {
+  private validators: readonly CategoryCollectionValidator[] = [
+    () => {},
+  ];
+
+  private validationContext
+  : CategoryCollectionValidationContext = new CategoryCollectionValidationContextStub();
+
+  public withValidators(validators: readonly CategoryCollectionValidator[]): this {
+    this.validators = validators;
+    return this;
+  }
+
+  public withValidationContext(validationContext: CategoryCollectionValidationContext): this {
+    this.validationContext = validationContext;
+    return this;
+  }
+
+  public runValidation(): ReturnType<typeof validateCategoryCollection> {
+    return validateCategoryCollection(
+      this.validationContext,
+      this.validators,
+    );
+  }
+}
diff --git a/tests/unit/domain/Collection/Validation/Rules/EnsureKnownOperatingSystem.spec.ts b/tests/unit/domain/Collection/Validation/Rules/EnsureKnownOperatingSystem.spec.ts
new file mode 100644
index 00000000..1195e383
--- /dev/null
+++ b/tests/unit/domain/Collection/Validation/Rules/EnsureKnownOperatingSystem.spec.ts
@@ -0,0 +1,21 @@
+import { describe } from 'vitest';
+import { OperatingSystem } from '@/domain/OperatingSystem';
+import { EnumRangeTestRunner } from '@tests/unit/application/Common/EnumRangeTestRunner';
+import { ensureKnownOperatingSystem } from '@/domain/Collection/Validation/Rules/EnsureKnownOperatingSystem';
+import { CategoryCollectionValidationContextStub } from '@tests/unit/shared/Stubs/CategoryCollectionValidationContextStub';
+
+describe('ensureKnownOperatingSystem', () => {
+  // act
+  const act = (os: OperatingSystem) => test(os);
+  // assert
+  new EnumRangeTestRunner(act)
+    .testValidValueDoesNotThrow(OperatingSystem.Android)
+    .testOutOfRangeThrows();
+});
+
+function test(operatingSystem: OperatingSystem):
+ReturnType<typeof ensureKnownOperatingSystem> {
+  const context = new CategoryCollectionValidationContextStub()
+    .withOperatingSystem(operatingSystem);
+  return ensureKnownOperatingSystem(context);
+}
diff --git a/tests/unit/domain/Collection/Validation/Rules/EnsurePresenceOfAllRecommendationLevels.spec.ts b/tests/unit/domain/Collection/Validation/Rules/EnsurePresenceOfAllRecommendationLevels.spec.ts
new file mode 100644
index 00000000..17d0175a
--- /dev/null
+++ b/tests/unit/domain/Collection/Validation/Rules/EnsurePresenceOfAllRecommendationLevels.spec.ts
@@ -0,0 +1,99 @@
+import { describe, it, expect } from 'vitest';
+import { RecommendationLevel } from '@/domain/Executables/Script/RecommendationLevel';
+import type { Script } from '@/domain/Executables/Script/Script';
+import { ensurePresenceOfAllRecommendationLevels } from '@/domain/Collection/Validation/Rules/EnsurePresenceOfAllRecommendationLevels';
+import { CategoryCollectionValidationContextStub } from '@tests/unit/shared/Stubs/CategoryCollectionValidationContextStub';
+import { ScriptStub } from '@tests/unit/shared/Stubs/ScriptStub';
+import { getEnumValues } from '@/application/Common/Enum';
+import { collectExceptionMessage } from '@tests/unit/shared/ExceptionCollector';
+
+describe('ensurePresenceOfAllRecommendationLevels', () => {
+  it('passes when all recommendation levels are present', () => {
+    // arrange
+    const scripts = getAllPossibleRecommendationLevels().map((level, index) => {
+      return new ScriptStub(`script-${index}`)
+        .withLevel(level);
+    });
+
+    // act
+    const act = () => test(scripts);
+
+    // assert
+    expect(act).to.not.throw();
+  });
+
+  describe('missing single level', () => {
+    // arrange
+    const recommendationLevels = getAllPossibleRecommendationLevels();
+    recommendationLevels.forEach((missingLevel) => {
+      const expectedDisplayName = getDisplayName(missingLevel);
+      it(`throws an error when when "${expectedDisplayName}" is missing`, () => {
+        const expectedError = `Missing recommendation levels: ${expectedDisplayName}.`;
+        const otherLevels = recommendationLevels.filter((level) => level !== missingLevel);
+        const scripts = otherLevels.map(
+          (level, index) => new ScriptStub(`script-${index}`).withLevel(level),
+        );
+        // act
+        const act = () => test(scripts);
+        // assert
+        expect(act).to.throw(expectedError);
+      });
+    });
+  });
+
+  it('throws an error with multiple missing recommendation levels', () => {
+    // arrange
+    const [
+      notExpectedLevelInError,
+      ...expectedLevelsInError
+    ] = getAllPossibleRecommendationLevels();
+    const scripts: Script[] = [
+      new ScriptStub('recommended').withLevel(notExpectedLevelInError),
+    ];
+
+    // act
+    const act = () => test(scripts);
+
+    // assert
+    const actualErrorMessage = collectExceptionMessage(act);
+    expectedLevelsInError.forEach((level) => {
+      const expectedLevelInError = getDisplayName(level);
+      expect(actualErrorMessage).to.include(expectedLevelInError);
+    });
+    expect(actualErrorMessage).to.not.include(getDisplayName(notExpectedLevelInError));
+  });
+
+  it('throws an error when no scripts are provided', () => {
+    // arrange
+    const expectedLevelsInError = getAllPossibleRecommendationLevels()
+      .map((level) => getDisplayName(level));
+    const scripts: Script[] = [];
+
+    // act
+    const act = () => test(scripts);
+
+    // assert
+    const actualErrorMessage = collectExceptionMessage(act);
+    expectedLevelsInError.forEach((expectedLevelInError) => {
+      expect(actualErrorMessage).to.include(expectedLevelInError);
+    });
+  });
+});
+
+function test(allScripts: Script[]):
+ReturnType<typeof ensurePresenceOfAllRecommendationLevels> {
+  const context = new CategoryCollectionValidationContextStub()
+    .withAllScripts(allScripts);
+  return ensurePresenceOfAllRecommendationLevels(context);
+}
+
+function getAllPossibleRecommendationLevels(): readonly (RecommendationLevel | undefined)[] {
+  return [
+    ...getEnumValues(RecommendationLevel),
+    undefined,
+  ];
+}
+
+function getDisplayName(level: RecommendationLevel | undefined): string {
+  return level === undefined ? 'None' : RecommendationLevel[level];
+}
diff --git a/tests/unit/domain/Collection/Validation/Rules/EnsurePresenceOfAtLeastOneCategory.spec.ts b/tests/unit/domain/Collection/Validation/Rules/EnsurePresenceOfAtLeastOneCategory.spec.ts
new file mode 100644
index 00000000..077e4703
--- /dev/null
+++ b/tests/unit/domain/Collection/Validation/Rules/EnsurePresenceOfAtLeastOneCategory.spec.ts
@@ -0,0 +1,39 @@
+import { describe, it, expect } from 'vitest';
+import { CategoryCollectionValidationContextStub } from '@tests/unit/shared/Stubs/CategoryCollectionValidationContextStub';
+import type { Category } from '@/domain/Executables/Category/Category';
+import { ensurePresenceOfAtLeastOneCategory } from '@/domain/Collection/Validation/Rules/EnsurePresenceOfAtLeastOneCategory';
+import { CategoryStub } from '@tests/unit/shared/Stubs/CategoryStub';
+
+describe('ensurePresenceOfAtLeastOneCategory', () => {
+  it('throws an error when no categories are present', () => {
+    // arrange
+    const expectedErrorMessage = 'Collection must have at least one category';
+    const categories: Category[] = [];
+
+    // act
+    const act = () => test(categories);
+
+    // assert
+    expect(act).to.throw(expectedErrorMessage);
+  });
+
+  it('does not throw an error when at least one category is present', () => {
+    // arrange
+    const categories: Category[] = [
+      new CategoryStub('existing-category'),
+    ];
+
+    // act
+    const act = () => test(categories);
+
+    // assert
+    expect(act).not.to.throw();
+  });
+});
+
+function test(allCategories: readonly Category[]):
+ReturnType<typeof ensurePresenceOfAtLeastOneCategory> {
+  const context = new CategoryCollectionValidationContextStub()
+    .withAllCategories(allCategories);
+  return ensurePresenceOfAtLeastOneCategory(context);
+}
diff --git a/tests/unit/domain/Collection/Validation/Rules/EnsurePresenceOfAtLeastOneScript.spec.ts b/tests/unit/domain/Collection/Validation/Rules/EnsurePresenceOfAtLeastOneScript.spec.ts
new file mode 100644
index 00000000..5f893e76
--- /dev/null
+++ b/tests/unit/domain/Collection/Validation/Rules/EnsurePresenceOfAtLeastOneScript.spec.ts
@@ -0,0 +1,39 @@
+import { describe, it, expect } from 'vitest';
+import { CategoryCollectionValidationContextStub } from '@tests/unit/shared/Stubs/CategoryCollectionValidationContextStub';
+import type { Script } from '@/domain/Executables/Script/Script';
+import { ensurePresenceOfAtLeastOneScript } from '@/domain/Collection/Validation/Rules/EnsurePresenceOfAtLeastOneScript';
+import { ScriptStub } from '@tests/unit/shared/Stubs/ScriptStub';
+
+describe('ensurePresenceOfAtLeastOneScript', () => {
+  it('throws an error when no scripts are present', () => {
+    // arrange
+    const expectedErrorMessage = 'Collection must have at least one script';
+    const scripts: Script[] = [];
+
+    // act
+    const act = () => test(scripts);
+
+    // assert
+    expect(act).to.throw(expectedErrorMessage);
+  });
+
+  it('does not throw an error when at least one category is present', () => {
+    // arrange
+    const scripts: Script[] = [
+      new ScriptStub('existing-script'),
+    ];
+
+    // act
+    const act = () => test(scripts);
+
+    // assert
+    expect(act).not.to.throw();
+  });
+});
+
+function test(allScripts: readonly Script[]):
+ReturnType<typeof ensurePresenceOfAtLeastOneScript> {
+  const context = new CategoryCollectionValidationContextStub()
+    .withAllScripts(allScripts);
+  return ensurePresenceOfAtLeastOneScript(context);
+}
diff --git a/tests/unit/domain/Collection/Validation/Rules/EnsureUniqueIdsAcrossExecutables.spec.ts b/tests/unit/domain/Collection/Validation/Rules/EnsureUniqueIdsAcrossExecutables.spec.ts
new file mode 100644
index 00000000..6069e754
--- /dev/null
+++ b/tests/unit/domain/Collection/Validation/Rules/EnsureUniqueIdsAcrossExecutables.spec.ts
@@ -0,0 +1,146 @@
+import { describe, it, expect } from 'vitest';
+import { ensureUniqueIdsAcrossExecutables } from '@/domain/Collection/Validation/Rules/EnsureUniqueIdsAcrossExecutables';
+import type { Category } from '@/domain/Executables/Category/Category';
+import type { Script } from '@/domain/Executables/Script/Script';
+import { CategoryCollectionValidationContextStub } from '@tests/unit/shared/Stubs/CategoryCollectionValidationContextStub';
+import { CategoryStub } from '@tests/unit/shared/Stubs/CategoryStub';
+import { ScriptStub } from '@tests/unit/shared/Stubs/ScriptStub';
+import type { ExecutableId } from '@/domain/Executables/Identifiable';
+
+describe('ensureUniqueIdsAcrossExecutables', () => {
+  it('does not throw an error when all IDs are unique', () => {
+    // arrange
+    const testData: TestData = {
+      categories: [
+        new CategoryStub('category1'),
+        new CategoryStub('category2'),
+      ],
+      scripts: [
+        new ScriptStub('script1'),
+        new ScriptStub('script2'),
+      ],
+    };
+
+    // act
+    const act = () => test(testData);
+
+    // assert
+    expect(act).to.not.throw();
+  });
+
+  it('throws an error when duplicate IDs are found across categories and scripts', () => {
+    // arrange
+    const duplicateId: ExecutableId = 'duplicate';
+    const expectedErrorMessage = `Duplicate executable IDs found: "${duplicateId}"`;
+    const testData: TestData = {
+      categories: [
+        new CategoryStub(duplicateId),
+        new CategoryStub('category2'),
+      ],
+      scripts: [
+        new ScriptStub(duplicateId),
+        new ScriptStub('script2'),
+      ],
+    };
+
+    // act
+    const act = () => test(testData);
+
+    // assert
+    expect(act).to.throw(expectedErrorMessage);
+  });
+
+  it('throws an error when duplicate IDs are found within categories', () => {
+    // arrange
+    const duplicateId: ExecutableId = 'duplicate';
+    const expectedErrorMessage = `Duplicate executable IDs found: "${duplicateId}"`;
+    const testData: TestData = {
+      categories: [
+        new CategoryStub(duplicateId),
+        new CategoryStub(duplicateId),
+      ],
+      scripts: [
+        new ScriptStub('script1'),
+        new ScriptStub('script2'),
+      ],
+    };
+
+    // act
+    const act = () => test(testData);
+
+    // assert
+    expect(act).to.throw(expectedErrorMessage);
+  });
+
+  it('throws an error when duplicate IDs are found within scripts', () => {
+    // arrange
+    const duplicateId: ExecutableId = 'duplicate';
+    const expectedErrorMessage = `Duplicate executable IDs found: "${duplicateId}"`;
+    const testData: TestData = {
+      categories: [
+        new CategoryStub('category1'),
+        new CategoryStub('category2'),
+      ],
+      scripts: [
+        new ScriptStub(duplicateId),
+        new ScriptStub(duplicateId),
+      ],
+    };
+
+    // act
+    const act = () => test(testData);
+
+    // assert
+    expect(act).to.throw(expectedErrorMessage);
+  });
+
+  it('throws an error with multiple duplicate IDs', () => {
+    // arrange
+    const duplicateId1: ExecutableId = 'duplicate-1';
+    const duplicateId2: ExecutableId = 'duplicate-2';
+    const expectedErrorMessage = `Duplicate executable IDs found: "${duplicateId1}", "${duplicateId2}"`;
+    const testData: TestData = {
+      categories: [
+        new CategoryStub(duplicateId1),
+        new CategoryStub(duplicateId2),
+      ],
+      scripts: [
+        new ScriptStub(duplicateId1),
+        new ScriptStub(duplicateId2),
+      ],
+    };
+
+    // act
+    const act = () => test(testData);
+
+    // assert
+    expect(act).to.throw(expectedErrorMessage);
+  });
+
+  it('handles empty categories and scripts arrays', () => {
+    // arrange
+    const testData: TestData = {
+      categories: [],
+      scripts: [],
+    };
+
+    // act
+    const act = () => test(testData);
+
+    // assert
+    expect(act).to.not.throw();
+  });
+});
+
+interface TestData {
+  readonly categories: readonly Category[];
+  readonly scripts: readonly Script[];
+}
+
+function test(testData: TestData):
+ReturnType<typeof ensureUniqueIdsAcrossExecutables> {
+  const context = new CategoryCollectionValidationContextStub()
+    .withAllCategories(testData.categories)
+    .withAllScripts(testData.scripts);
+  return ensureUniqueIdsAcrossExecutables(context);
+}
diff --git a/tests/unit/domain/Executables/Category/CategoryFactory.spec.ts b/tests/unit/domain/Executables/Category/CategoryFactory.spec.ts
new file mode 100644
index 00000000..b61acfc8
--- /dev/null
+++ b/tests/unit/domain/Executables/Category/CategoryFactory.spec.ts
@@ -0,0 +1,316 @@
+import { describe, it, expect } from 'vitest';
+import { CategoryStub } from '@tests/unit/shared/Stubs/CategoryStub';
+import { ScriptStub } from '@tests/unit/shared/Stubs/ScriptStub';
+import { itEachAbsentStringValue } from '@tests/unit/shared/TestCases/AbsentTests';
+import type { Category } from '@/domain/Executables/Category/Category';
+import type { Script } from '@/domain/Executables/Script/Script';
+import { createCategory } from '@/domain/Executables/Category/CategoryFactory';
+import type { ExecutableId } from '@/domain/Executables/Identifiable';
+
+describe('CategoryFactory', () => {
+  describe('createCategory', () => {
+    describe('id', () => {
+      it('assigns id correctly', () => {
+        // arrange
+        const expectedId: ExecutableId = 'expected category id';
+        // act
+        const category = new TestContext()
+          .withId(expectedId)
+          .build();
+        // assert
+        const actualId = category.executableId;
+        expect(actualId).to.equal(expectedId);
+      });
+      describe('throws error if id is absent', () => {
+        itEachAbsentStringValue((absentValue) => {
+          // arrange
+          const expectedError = 'missing ID';
+          const id = absentValue;
+          // act
+          const construct = () => new TestContext()
+            .withId(id)
+            .build();
+          // assert
+          expect(construct).to.throw(expectedError);
+        }, { excludeNull: true, excludeUndefined: true });
+      });
+    });
+    describe('name', () => {
+      it('assigns name correctly', () => {
+        // arrange
+        const expectedName = 'expected category name';
+        // act
+        const category = new TestContext()
+          .withName(expectedName)
+          .build();
+        // assert
+        const actualName = category.name;
+        expect(actualName).to.equal(expectedName);
+      });
+      describe('throws error if name is absent', () => {
+        itEachAbsentStringValue((absentValue) => {
+          // arrange
+          const expectedError = 'missing name';
+          const name = absentValue;
+          // act
+          const construct = () => new TestContext()
+            .withName(name)
+            .build();
+          // assert
+          expect(construct).to.throw(expectedError);
+        }, { excludeNull: true, excludeUndefined: true });
+      });
+    });
+    describe('docs', () => {
+      it('assigns docs correctly', () => {
+        // arrange
+        const expectedDocs = ['expected', 'docs'];
+        // act
+        const category = new TestContext()
+          .withDocs(expectedDocs)
+          .build();
+        // assert
+        const actualDocs = category.docs;
+        expect(actualDocs).to.equal(expectedDocs);
+      });
+    });
+    describe('children', () => {
+      it('assigns scripts correctly', () => {
+        // arrange
+        const expectedScripts = [
+          new ScriptStub('expected-script-1'),
+          new ScriptStub('expected-script-2'),
+        ];
+        // act
+        const category = new TestContext()
+          .withScripts(expectedScripts)
+          .build();
+        // assert
+        const actualScripts = category.scripts;
+        expect(actualScripts).to.equal(expectedScripts);
+      });
+      it('assigns categories correctly', () => {
+        // arrange
+        const expectedCategories = [
+          new CategoryStub('expected-subcategory-1'),
+          new CategoryStub('expected-subcategory-2'),
+        ];
+        // act
+        const category = new TestContext()
+          .withSubcategories(expectedCategories)
+          .build();
+        // assert
+        const actualCategories = category.subcategories;
+        expect(actualCategories).to.equal(expectedCategories);
+      });
+      it('throws error if no children are present', () => {
+        // arrange
+        const expectedError = 'A category must have at least one sub-category or script';
+        const scriptChildren: readonly Script[] = [];
+        const categoryChildren: readonly Category[] = [];
+        // act
+        const construct = () => new TestContext()
+          .withSubcategories(categoryChildren)
+          .withScripts(scriptChildren)
+          .build();
+        // assert
+        expect(construct).to.throw(expectedError);
+      });
+    });
+    describe('getAllScriptsRecursively', () => {
+      it('retrieves direct child scripts', () => {
+        // arrange
+        const expectedScripts: readonly Script[] = [
+          new ScriptStub('expected-script-1'),
+          new ScriptStub('expected-script-2'),
+        ];
+        const category = new TestContext()
+          .withScripts(expectedScripts)
+          .build();
+        // act
+        const actual = category.getAllScriptsRecursively();
+        // assert
+        expect(actual).to.have.deep.members(expectedScripts);
+      });
+      it('retrieves scripts from direct child categories', () => {
+        // arrange
+        const expectedScriptIds: readonly string[] = [
+          '1', '2', '3', '4',
+        ];
+        const subcategories: readonly Category[] = [
+          new CategoryStub('subcategory-1').withScriptIds('1', '2'),
+          new CategoryStub('subcategory-2').withScriptIds('3', '4'),
+        ];
+        const category = new TestContext()
+          .withScripts([])
+          .withSubcategories(subcategories)
+          .build();
+        // act
+        const actualIds = category
+          .getAllScriptsRecursively()
+          .map((s) => s.executableId);
+        // assert
+        expect(actualIds).to.have.deep.members(expectedScriptIds);
+      });
+      it('retrieves scripts from both direct children and child categories', () => {
+        // arrange
+        const expectedScriptIds: readonly string[] = [
+          '1', '2', '3', '4', '5', '6',
+        ];
+        const subcategories: readonly Category[] = [
+          new CategoryStub('subcategory-1').withScriptIds('1', '2'),
+          new CategoryStub('subcategory-2').withScriptIds('3', '4'),
+        ];
+        const scripts: readonly Script[] = [
+          new ScriptStub('5'),
+          new ScriptStub('6'),
+        ];
+        const category = new TestContext()
+          .withSubcategories(subcategories)
+          .withScripts(scripts)
+          .build();
+        // act
+        const actualIds = category
+          .getAllScriptsRecursively()
+          .map((s) => s.executableId);
+        // assert
+        expect(actualIds).to.have.deep.members(expectedScriptIds);
+      });
+      it('retrieves scripts from nested categories recursively', () => {
+        // arrange
+        const expectedScriptIds: readonly string[] = [
+          '1', '2', '3', '4', '5', '6',
+        ];
+        const subcategories: readonly Category[] = [
+          new CategoryStub('subcategory-1')
+            .withScriptIds('1', '2')
+            .withCategory(
+              new CategoryStub('subcategory-1-subcategory-1')
+                .withScriptIds('3', '4'),
+            ),
+          new CategoryStub('subcategory-2')
+            .withCategories(
+              new CategoryStub('subcategory-2-subcategory-1')
+                .withScriptIds('5')
+                .withCategory(
+                  new CategoryStub('subcategory-2-subcategory-1-subcategory-1')
+                    .withCategory(
+                      new CategoryStub('subcategory-2-subcategory-1-subcategory-1-subcategory-1')
+                        .withScriptIds('6'),
+                    ),
+                ),
+            ),
+        ];
+        // assert
+        const category = new TestContext()
+          .withScripts([])
+          .withSubcategories(subcategories)
+          .build();
+        // act
+        const actualIds = category
+          .getAllScriptsRecursively()
+          .map((s) => s.executableId);
+        // assert
+        expect(actualIds).to.have.deep.members(expectedScriptIds);
+      });
+    });
+    describe('includes', () => {
+      it('returns false for scripts not included', () => {
+        // assert
+        const expectedResult = false;
+        const script = new ScriptStub('3');
+        const childCategory = new CategoryStub('subcategory')
+          .withScriptIds('1', '2');
+        const category = new TestContext()
+          .withSubcategories([childCategory])
+          .build();
+        // act
+        const actual = category.includes(script);
+        // assert
+        expect(actual).to.equal(expectedResult);
+      });
+      it('returns true for scripts directly included', () => {
+        // assert
+        const expectedResult = true;
+        const script = new ScriptStub('3');
+        const childCategory = new CategoryStub('subcategory')
+          .withScript(script)
+          .withScriptIds('non-related');
+        const category = new TestContext()
+          .withSubcategories([childCategory])
+          .build();
+        // act
+        const actual = category.includes(script);
+        // assert
+        expect(actual).to.equal(expectedResult);
+      });
+      it('returns true for scripts included in nested categories', () => {
+        // assert
+        const expectedResult = true;
+        const script = new ScriptStub('3');
+        const childCategory = new CategoryStub('subcategory')
+          .withScriptIds('non-related')
+          .withCategory(
+            new CategoryStub('nested-subcategory')
+              .withScript(script),
+          );
+        const category = new TestContext()
+          .withSubcategories([childCategory])
+          .build();
+        // act
+        const actual = category.includes(script);
+        // assert
+        expect(actual).to.equal(expectedResult);
+      });
+    });
+  });
+});
+
+class TestContext {
+  private id = `[${TestContext.name}] test category`;
+
+  private name = 'test-category';
+
+  private docs: ReadonlyArray<string> = [];
+
+  private subcategories: ReadonlyArray<Category> = [];
+
+  private scripts: ReadonlyArray<Script> = [
+    new ScriptStub(`[${TestContext.name}] script`),
+  ];
+
+  public withId(id: string): this {
+    this.id = id;
+    return this;
+  }
+
+  public withName(name: string): this {
+    this.name = name;
+    return this;
+  }
+
+  public withDocs(docs: ReadonlyArray<string>): this {
+    this.docs = docs;
+    return this;
+  }
+
+  public withScripts(scripts: ReadonlyArray<Script>): this {
+    this.scripts = scripts;
+    return this;
+  }
+
+  public withSubcategories(subcategories: ReadonlyArray<Category>): this {
+    this.subcategories = subcategories;
+    return this;
+  }
+
+  public build(): ReturnType<typeof createCategory> {
+    return createCategory({
+      executableId: this.id,
+      name: this.name,
+      docs: this.docs,
+      subcategories: this.subcategories,
+      scripts: this.scripts,
+    });
+  }
+}
diff --git a/tests/unit/domain/Executables/Category/CollectionCategory.spec.ts b/tests/unit/domain/Executables/Category/CollectionCategory.spec.ts
deleted file mode 100644
index 1c4268db..00000000
--- a/tests/unit/domain/Executables/Category/CollectionCategory.spec.ts
+++ /dev/null
@@ -1,217 +0,0 @@
-import { describe, it, expect } from 'vitest';
-import { CollectionCategory } from '@/domain/Executables/Category/CollectionCategory';
-import { CategoryStub } from '@tests/unit/shared/Stubs/CategoryStub';
-import { ScriptStub } from '@tests/unit/shared/Stubs/ScriptStub';
-import { itEachAbsentStringValue } from '@tests/unit/shared/TestCases/AbsentTests';
-import type { Category } from '@/domain/Executables/Category/Category';
-import type { Script } from '@/domain/Executables/Script/Script';
-
-describe('CollectionCategory', () => {
-  describe('ctor', () => {
-    describe('throws error if name is absent', () => {
-      itEachAbsentStringValue((absentValue) => {
-        // arrange
-        const expectedError = 'missing name';
-        const name = absentValue;
-        // act
-        const construct = () => new CategoryBuilder()
-          .withName(name)
-          .build();
-        // assert
-        expect(construct).to.throw(expectedError);
-      }, { excludeNull: true, excludeUndefined: true });
-    });
-    it('throws error if no children are present', () => {
-      // arrange
-      const expectedError = 'A category must have at least one sub-category or script';
-      const scriptChildren: readonly Script[] = [];
-      const categoryChildren: readonly Category[] = [];
-      // act
-      const construct = () => new CategoryBuilder()
-        .withSubcategories(categoryChildren)
-        .withScripts(scriptChildren)
-        .build();
-      // assert
-      expect(construct).to.throw(expectedError);
-    });
-  });
-  describe('getAllScriptsRecursively', () => {
-    it('retrieves direct child scripts', () => {
-      // arrange
-      const expectedScripts = [new ScriptStub('1'), new ScriptStub('2')];
-      const sut = new CategoryBuilder()
-        .withScripts(expectedScripts)
-        .build();
-      // act
-      const actual = sut.getAllScriptsRecursively();
-      // assert
-      expect(actual).to.have.deep.members(expectedScripts);
-    });
-    it('retrieves scripts from direct child categories', () => {
-      // arrange
-      const expectedScriptIds = ['1', '2', '3', '4'];
-      const categories = [
-        new CategoryStub(31).withScriptIds('1', '2'),
-        new CategoryStub(32).withScriptIds('3', '4'),
-      ];
-      const sut = new CategoryBuilder()
-        .withScripts([])
-        .withSubcategories(categories)
-        .build();
-      // act
-      const actualIds = sut
-        .getAllScriptsRecursively()
-        .map((s) => s.id);
-      // assert
-      expect(actualIds).to.have.deep.members(expectedScriptIds);
-    });
-    it('retrieves scripts from both direct children and child categories', () => {
-      // arrange
-      const expectedScriptIds = ['1', '2', '3', '4', '5', '6'];
-      const categories = [
-        new CategoryStub(31).withScriptIds('1', '2'),
-        new CategoryStub(32).withScriptIds('3', '4'),
-      ];
-      const scripts = [new ScriptStub('5'), new ScriptStub('6')];
-      const sut = new CategoryBuilder()
-        .withSubcategories(categories)
-        .withScripts(scripts)
-        .build();
-      // act
-      const actualIds = sut
-        .getAllScriptsRecursively()
-        .map((s) => s.id);
-      // assert
-      expect(actualIds).to.have.deep.members(expectedScriptIds);
-    });
-    it('retrieves scripts from nested categories recursively', () => {
-      // arrange
-      const expectedScriptIds = ['1', '2', '3', '4', '5', '6'];
-      const categories = [
-        new CategoryStub(31)
-          .withScriptIds('1', '2')
-          .withCategory(
-            new CategoryStub(32)
-              .withScriptIds('3', '4'),
-          ),
-        new CategoryStub(33)
-          .withCategories(
-            new CategoryStub(34)
-              .withScriptIds('5')
-              .withCategory(
-                new CategoryStub(35)
-                  .withCategory(
-                    new CategoryStub(35).withScriptIds('6'),
-                  ),
-              ),
-          ),
-      ];
-      // assert
-      const sut = new CategoryBuilder()
-        .withScripts([])
-        .withSubcategories(categories)
-        .build();
-      // act
-      const actualIds = sut
-        .getAllScriptsRecursively()
-        .map((s) => s.id);
-      // assert
-      expect(actualIds).to.have.deep.members(expectedScriptIds);
-    });
-  });
-  describe('includes', () => {
-    it('returns false for scripts not included', () => {
-      // assert
-      const expectedResult = false;
-      const script = new ScriptStub('3');
-      const childCategory = new CategoryStub(33)
-        .withScriptIds('1', '2');
-      const sut = new CategoryBuilder()
-        .withSubcategories([childCategory])
-        .build();
-      // act
-      const actual = sut.includes(script);
-      // assert
-      expect(actual).to.equal(expectedResult);
-    });
-    it('returns true for scripts directly included', () => {
-      // assert
-      const expectedResult = true;
-      const script = new ScriptStub('3');
-      const childCategory = new CategoryStub(33)
-        .withScript(script)
-        .withScriptIds('non-related');
-      const sut = new CategoryBuilder()
-        .withSubcategories([childCategory])
-        .build();
-      // act
-      const actual = sut.includes(script);
-      // assert
-      expect(actual).to.equal(expectedResult);
-    });
-    it('returns true for scripts included in nested categories', () => {
-      // assert
-      const expectedResult = true;
-      const script = new ScriptStub('3');
-      const childCategory = new CategoryStub(22)
-        .withScriptIds('non-related')
-        .withCategory(new CategoryStub(33).withScript(script));
-      const sut = new CategoryBuilder()
-        .withSubcategories([childCategory])
-        .build();
-      // act
-      const actual = sut.includes(script);
-      // assert
-      expect(actual).to.equal(expectedResult);
-    });
-  });
-});
-
-class CategoryBuilder {
-  private id = 3264;
-
-  private name = 'test-script';
-
-  private docs: ReadonlyArray<string> = [];
-
-  private subcategories: ReadonlyArray<Category> = [];
-
-  private scripts: ReadonlyArray<Script> = [
-    new ScriptStub(`[${CategoryBuilder.name}] script`),
-  ];
-
-  public withId(id: number): this {
-    this.id = id;
-    return this;
-  }
-
-  public withName(name: string): this {
-    this.name = name;
-    return this;
-  }
-
-  public withDocs(docs: ReadonlyArray<string>): this {
-    this.docs = docs;
-    return this;
-  }
-
-  public withScripts(scripts: ReadonlyArray<Script>): this {
-    this.scripts = scripts;
-    return this;
-  }
-
-  public withSubcategories(subcategories: ReadonlyArray<Category>): this {
-    this.subcategories = subcategories;
-    return this;
-  }
-
-  public build(): CollectionCategory {
-    return new CollectionCategory({
-      id: this.id,
-      name: this.name,
-      docs: this.docs,
-      subcategories: this.subcategories,
-      scripts: this.scripts,
-    });
-  }
-}
diff --git a/tests/unit/domain/Executables/Script/CollectionScript.spec.ts b/tests/unit/domain/Executables/Script/ScriptFactory.spec.ts
similarity index 60%
rename from tests/unit/domain/Executables/Script/CollectionScript.spec.ts
rename to tests/unit/domain/Executables/Script/ScriptFactory.spec.ts
index 753aaf3f..9432afc7 100644
--- a/tests/unit/domain/Executables/Script/CollectionScript.spec.ts
+++ b/tests/unit/domain/Executables/Script/ScriptFactory.spec.ts
@@ -1,21 +1,35 @@
 import { describe, it, expect } from 'vitest';
 import { getEnumValues } from '@/application/Common/Enum';
-import { CollectionScript } from '@/domain/Executables/Script/CollectionScript';
 import { RecommendationLevel } from '@/domain/Executables/Script/RecommendationLevel';
 import type { ScriptCode } from '@/domain/Executables/Script/Code/ScriptCode';
 import { ScriptCodeStub } from '@tests/unit/shared/Stubs/ScriptCodeStub';
+import { createScript } from '@/domain/Executables/Script/ScriptFactory';
+import type { ExecutableId } from '@/domain/Executables/Identifiable';
 
-describe('CollectionScript', () => {
-  describe('ctor', () => {
+describe('ScriptFactory', () => {
+  describe('createScript', () => {
+    describe('id', () => {
+      it('correctly assigns id', () => {
+        // arrange
+        const expectedId: ExecutableId = 'expected-id';
+        // act
+        const script = new TestContext()
+          .withId(expectedId)
+          .build();
+        // assert
+        const actualId = script.executableId;
+        expect(actualId).to.equal(expectedId);
+      });
+    });
     describe('scriptCode', () => {
       it('assigns code correctly', () => {
         // arrange
         const expected = new ScriptCodeStub();
-        const sut = new ScriptBuilder()
+        const script = new TestContext()
           .withCode(expected)
           .build();
         // act
-        const actual = sut.code;
+        const actual = script.code;
         // assert
         expect(actual).to.deep.equal(expected);
       });
@@ -23,21 +37,21 @@ describe('CollectionScript', () => {
     describe('canRevert', () => {
       it('returns false without revert code', () => {
         // arrange
-        const sut = new ScriptBuilder()
+        const script = new TestContext()
           .withCodes('code')
           .build();
         // act
-        const actual = sut.canRevert();
+        const actual = script.canRevert();
         // assert
         expect(actual).to.equal(false);
       });
       it('returns true with revert code', () => {
         // arrange
-        const sut = new ScriptBuilder()
+        const script = new TestContext()
           .withCodes('code', 'non empty revert code')
           .build();
         // act
-        const actual = sut.canRevert();
+        const actual = script.canRevert();
         // assert
         expect(actual).to.equal(true);
       });
@@ -48,7 +62,7 @@ describe('CollectionScript', () => {
         const invalidValue: RecommendationLevel = 55 as never;
         const expectedError = 'invalid level';
         // act
-        const construct = () => new ScriptBuilder()
+        const construct = () => new TestContext()
           .withRecommendationLevel(invalidValue)
           .build();
         // assert
@@ -58,43 +72,46 @@ describe('CollectionScript', () => {
         // arrange
         const expected = undefined;
         // act
-        const sut = new ScriptBuilder()
+        const script = new TestContext()
           .withRecommendationLevel(expected)
           .build();
         // assert
-        expect(sut.level).to.equal(expected);
+        expect(script.level).to.equal(expected);
       });
       it('correctly assigns valid recommendation levels', () => {
-        // arrange
-        for (const expected of getEnumValues(RecommendationLevel)) {
+        getEnumValues(RecommendationLevel).forEach((enumValue) => {
+          // arrange
+          const expectedRecommendationLevel = enumValue;
           // act
-          const sut = new ScriptBuilder()
-            .withRecommendationLevel(expected)
+          const script = new TestContext()
+            .withRecommendationLevel(expectedRecommendationLevel)
             .build();
           // assert
-          const actual = sut.level;
-          expect(actual).to.equal(expected);
-        }
+          const actualRecommendationLevel = script.level;
+          expect(actualRecommendationLevel).to.equal(expectedRecommendationLevel);
+        });
       });
     });
     describe('docs', () => {
       it('correctly assigns docs', () => {
         // arrange
-        const expected = ['doc1', 'doc2'];
+        const expectedDocs = ['doc1', 'doc2'];
         // act
-        const sut = new ScriptBuilder()
-          .withDocs(expected)
+        const script = new TestContext()
+          .withDocs(expectedDocs)
           .build();
-        const actual = sut.docs;
         // assert
-        expect(actual).to.equal(expected);
+        const actualDocs = script.docs;
+        expect(actualDocs).to.equal(expectedDocs);
       });
     });
   });
 });
 
-class ScriptBuilder {
-  private name = 'test-script';
+class TestContext {
+  private name = `[${TestContext.name}]test-script`;
+
+  private id: ExecutableId = `[${TestContext.name}]id`;
 
   private code: ScriptCode = new ScriptCodeStub();
 
@@ -109,6 +126,11 @@ class ScriptBuilder {
     return this;
   }
 
+  public withId(id: ExecutableId): this {
+    this.id = id;
+    return this;
+  }
+
   public withCode(code: ScriptCode): this {
     this.code = code;
     return this;
@@ -129,8 +151,9 @@ class ScriptBuilder {
     return this;
   }
 
-  public build(): CollectionScript {
-    return new CollectionScript({
+  public build(): ReturnType<typeof createScript> {
+    return createScript({
+      executableId: this.id,
       name: this.name,
       code: this.code,
       docs: this.docs,
diff --git a/tests/unit/infrastructure/InMemoryRepository.spec.ts b/tests/unit/infrastructure/InMemoryRepository.spec.ts
index 66dfcb96..1f589a48 100644
--- a/tests/unit/infrastructure/InMemoryRepository.spec.ts
+++ b/tests/unit/infrastructure/InMemoryRepository.spec.ts
@@ -1,125 +1,180 @@
 import { describe, it, expect } from 'vitest';
-import { NumericEntityStub } from '@tests/unit/shared/Stubs/NumericEntityStub';
 import { InMemoryRepository } from '@/infrastructure/Repository/InMemoryRepository';
+import { RepositoryEntityStub } from '@tests/unit/shared/Stubs/RepositoryEntityStub';
+import type { RepositoryEntity, RepositoryEntityId } from '@/application/Repository/RepositoryEntity';
 
 describe('InMemoryRepository', () => {
   describe('exists', () => {
-    const sut = new InMemoryRepository<number, NumericEntityStub>(
-      [new NumericEntityStub(1), new NumericEntityStub(2), new NumericEntityStub(3)],
-    );
-
-    describe('item exists', () => {
-      const actual = sut.exists(1);
-      it('returns true', () => expect(actual).to.be.true);
+    it('returns true when item exists', () => {
+      // arrange
+      const expectedExistence = true;
+      const existingItemId: RepositoryEntityId = 'existing-entity-id';
+      const items: readonly RepositoryEntity[] = [
+        new RepositoryEntityStub('unrelated-entity-1'),
+        new RepositoryEntityStub(existingItemId),
+        new RepositoryEntityStub('unrelated-entity-2'),
+      ];
+      const sut = new InMemoryRepository(items);
+      // act
+      const actualExistence = sut.exists(existingItemId);
+      // assert
+      expect(actualExistence).to.equal(expectedExistence);
     });
-    describe('item does not exist', () => {
-      const actual = sut.exists(99);
-      it('returns false', () => expect(actual).to.be.false);
+    it('returns false when item does not exist', () => {
+      // arrange
+      const expectedExistence = false;
+      const absentItemId: RepositoryEntityId = 'id-that-does-not-belong';
+      const items: readonly RepositoryEntity[] = [
+        new RepositoryEntityStub('unrelated-entity-1'),
+        new RepositoryEntityStub('unrelated-entity-2'),
+      ];
+      const sut = new InMemoryRepository(items);
+      // act
+      const actualExistence = sut.exists(absentItemId);
+      // assert
+      expect(actualExistence).to.equal(expectedExistence);
     });
   });
-  it('getItems gets initial items', () => {
-    // arrange
-    const expected = [
-      new NumericEntityStub(1), new NumericEntityStub(2),
-      new NumericEntityStub(3), new NumericEntityStub(4),
-    ];
-
-    // act
-    const sut = new InMemoryRepository<number, NumericEntityStub>(expected);
-    const actual = sut.getItems();
-
-    // assert
-    expect(actual).to.deep.equal(expected);
+  describe('getItems', () => {
+    it('returns initial items', () => {
+      // arrange
+      const expectedItems: readonly RepositoryEntity[] = [
+        new RepositoryEntityStub('expected-item-1'),
+        new RepositoryEntityStub('expected-item-2'),
+        new RepositoryEntityStub('expected-item-3'),
+      ];
+      // act
+      const sut = new InMemoryRepository(expectedItems);
+      const actualItems = sut.getItems();
+      // assert
+      expect(actualItems).to.have.lengthOf(expectedItems.length);
+      expect(actualItems).to.deep.members(expectedItems);
+    });
   });
   describe('addItem', () => {
-    it('adds', () => {
+    it('increases length', () => {
       // arrange
-      const sut = new InMemoryRepository<number, NumericEntityStub>();
-      const expected = {
-        length: 1,
-        item: new NumericEntityStub(1),
-      };
+      const sut = new InMemoryRepository<RepositoryEntity>();
+      const expectedLength = 1;
 
       // act
-      sut.addItem(expected.item);
-      const actual = {
-        length: sut.length,
-        item: sut.getItems()[0],
-      };
+      sut.addItem(new RepositoryEntityStub('unrelated-id'));
 
       // assert
-      expect(actual.length).to.equal(expected.length);
-      expect(actual.item).to.deep.equal(expected.item);
+      const actualLength = sut.length;
+      expect(actualLength).to.equal(expectedLength);
     });
-  });
-  it('removeItem removes', () => {
-    // arrange
-    const initialItems = [
-      new NumericEntityStub(1), new NumericEntityStub(2),
-      new NumericEntityStub(3), new NumericEntityStub(4),
-    ];
-    const idToDelete = 3;
-    const expected = {
-      length: 3,
-      items: [new NumericEntityStub(1), new NumericEntityStub(2), new NumericEntityStub(4)],
-    };
-    const sut = new InMemoryRepository<number, NumericEntityStub>(initialItems);
+    it('adds as item', () => {
+      // arrange
+      const sut = new InMemoryRepository<RepositoryEntity>();
+      const expectedItem = new RepositoryEntityStub('expected-entity-id');
 
-    // act
-    sut.removeItem(idToDelete);
-    const actual = {
-      length: sut.length,
-      items: sut.getItems(),
-    };
+      // act
+      sut.addItem(expectedItem);
 
-    // assert
-    expect(actual.length).to.equal(expected.length);
-    expect(actual.items).to.deep.equal(expected.items);
+      // assert
+      const actualItems = sut.getItems();
+      expect(actualItems).to.have.lengthOf(1);
+      expect(actualItems).to.deep.include(expectedItem);
+    });
+  });
+  describe('removeItem', () => {
+    it('decreases length', () => {
+      // arrange
+      const itemIdToDelete: RepositoryEntityId = 'entity-id-to-be-deleted';
+      const initialItems: readonly RepositoryEntity[] = [
+        new RepositoryEntityStub('entity-to-be-retained-1'),
+        new RepositoryEntityStub(itemIdToDelete),
+        new RepositoryEntityStub('entity-to-be-retained-2'),
+      ];
+      const expectedLength = 2;
+      const sut = new InMemoryRepository<RepositoryEntity>(initialItems);
+      // act
+      sut.removeItem(itemIdToDelete);
+      // assert
+      const actualLength = sut.length;
+      expect(actualLength).to.equal(expectedLength);
+    });
+    it('removes from items', () => {
+      // arrange
+      const expectedItems: readonly RepositoryEntity[] = [
+        new RepositoryEntityStub('entity-to-be-retained-1'),
+        new RepositoryEntityStub('entity-to-be-retained-2'),
+      ];
+      const itemIdToDelete: RepositoryEntityId = 'entity-id-to-be-deleted';
+      const initialItems: readonly RepositoryEntity[] = [
+        ...expectedItems,
+        new RepositoryEntityStub(itemIdToDelete),
+      ];
+      const sut = new InMemoryRepository<RepositoryEntity>(initialItems);
+      // act
+      sut.removeItem(itemIdToDelete);
+      // assert
+      const actualItems = sut.getItems();
+      expect(actualItems).to.have.lengthOf(expectedItems.length);
+      expect(actualItems).to.have.deep.members(expectedItems);
+    });
   });
   describe('addOrUpdateItem', () => {
     it('adds when item does not exist', () => {
       // arrange
-      const initialItems = [new NumericEntityStub(1), new NumericEntityStub(2)];
-      const newItem = new NumericEntityStub(3);
-      const expected = [...initialItems, newItem];
-      const sut = new InMemoryRepository<number, NumericEntityStub>(initialItems);
+      const initialItems: readonly RepositoryEntity[] = [
+        new RepositoryEntityStub('existing-item-1'),
+        new RepositoryEntityStub('existing-item-2'),
+      ];
+      const newItem = new RepositoryEntityStub('new-item');
+      const expectedItems: readonly RepositoryEntity[] = [
+        ...initialItems,
+        newItem,
+      ];
+      const sut = new InMemoryRepository(initialItems);
       // act
       sut.addOrUpdateItem(newItem);
       // assert
-      const actual = sut.getItems();
-      expect(actual).to.deep.equal(expected);
+      const actualItems = sut.getItems();
+      expect(actualItems).to.have.lengthOf(expectedItems.length);
+      expect(actualItems).to.have.members(expectedItems);
     });
     it('updates when item exists', () => {
       // arrange
-      const initialItems = [new NumericEntityStub(1).withCustomProperty('bca')];
-      const updatedItem = new NumericEntityStub(1).withCustomProperty('abc');
-      const expected = [updatedItem];
-      const sut = new InMemoryRepository<number, NumericEntityStub>(initialItems);
+      const itemId: RepositoryEntityId = 'same-item-id';
+      const initialItems: readonly RepositoryEntity[] = [
+        new RepositoryEntityStub(itemId)
+          .withCustomPropertyValue('initial-property-value'),
+      ];
+      const updatedItem = new RepositoryEntityStub(itemId)
+        .withCustomPropertyValue('changed-property-value');
+      const sut = new InMemoryRepository(initialItems);
       // act
       sut.addOrUpdateItem(updatedItem);
       // assert
-      const actual = sut.getItems();
-      expect(actual).to.deep.equal(expected);
+      const actualItems = sut.getItems();
+      expect(actualItems).to.have.lengthOf(1);
+      expect(actualItems[0]).to.equal(updatedItem);
     });
   });
   describe('getById', () => {
     it('returns entity if it exists', () => {
       // arrange
-      const expected = new NumericEntityStub(1).withCustomProperty('bca');
-      const sut = new InMemoryRepository<number, NumericEntityStub>([
-        expected, new NumericEntityStub(2).withCustomProperty('bca'),
-        new NumericEntityStub(3).withCustomProperty('bca'), new NumericEntityStub(4).withCustomProperty('bca'),
-      ]);
+      const existingId: RepositoryEntityId = 'existing-item-id';
+      const expectedItem = new RepositoryEntityStub(existingId)
+        .withCustomPropertyValue('bca');
+      const initialItems: readonly RepositoryEntity[] = [
+        new RepositoryEntityStub('unrelated-entity'),
+        expectedItem,
+        new RepositoryEntityStub('different-id-same-property').withCustomPropertyValue('bca'),
+      ];
+      const sut = new InMemoryRepository(initialItems);
       // act
-      const actual = sut.getById(expected.id);
+      const actualItem = sut.getById(expectedItem.id);
       // assert
-      expect(actual).to.deep.equal(expected);
+      expect(actualItem).to.deep.equal(expectedItem);
     });
     it('throws if item does not exist', () => {
       // arrange
-      const id = 31;
+      const id: RepositoryEntityId = 'id-that-does-not-exist';
       const expectedError = `missing item: ${id}`;
-      const sut = new InMemoryRepository<number, NumericEntityStub>([]);
+      const sut = new InMemoryRepository<RepositoryEntityStub>();
       // act
       const act = () => sut.getById(id);
       // assert
diff --git a/tests/unit/presentation/components/Scripts/Menu/Recommendation/RecommendationStatusHandler.spec.ts b/tests/unit/presentation/components/Scripts/Menu/Recommendation/RecommendationStatusHandler.spec.ts
index d862d1bf..cc604a14 100644
--- a/tests/unit/presentation/components/Scripts/Menu/Recommendation/RecommendationStatusHandler.spec.ts
+++ b/tests/unit/presentation/components/Scripts/Menu/Recommendation/RecommendationStatusHandler.spec.ts
@@ -145,7 +145,7 @@ describe('RecommendationStatusHandler', () => {
           return `total: ${testCase.selection.length}\n`
             + 'scripts:\n'
             + testCase.selection
-              .map((s) => `{ id: ${s.script.id}, level: ${s.script.level === undefined ? 'unknown' : RecommendationLevel[s.script.level]} }`)
+              .map((s) => `{ id: ${s.script.executableId}, level: ${s.script.level === undefined ? 'unknown' : RecommendationLevel[s.script.level]} }`)
               .join(' | ');
         }
       });
diff --git a/tests/unit/presentation/components/Scripts/View/Tree/NodeContent/Reverter/CategoryReverter.spec.ts b/tests/unit/presentation/components/Scripts/View/Tree/NodeContent/Reverter/CategoryReverter.spec.ts
index 30d52049..dbd871e2 100644
--- a/tests/unit/presentation/components/Scripts/View/Tree/NodeContent/Reverter/CategoryReverter.spec.ts
+++ b/tests/unit/presentation/components/Scripts/View/Tree/NodeContent/Reverter/CategoryReverter.spec.ts
@@ -3,12 +3,12 @@ import { CategoryReverter } from '@/presentation/components/Scripts/View/Tree/No
 import { CategoryStub } from '@tests/unit/shared/Stubs/CategoryStub';
 import { CategoryCollectionStub } from '@tests/unit/shared/Stubs/CategoryCollectionStub';
 import { ScriptStub } from '@tests/unit/shared/Stubs/ScriptStub';
-import { getCategoryNodeId } from '@/presentation/components/Scripts/View/Tree/TreeViewAdapter/CategoryNodeMetadataConverter';
 import { UserSelectionStub } from '@tests/unit/shared/Stubs/UserSelectionStub';
 import { SelectedScriptStub } from '@tests/unit/shared/Stubs/SelectedScriptStub';
 import type { SelectedScript } from '@/application/Context/State/Selection/Script/SelectedScript';
 import { CategorySelectionStub } from '@tests/unit/shared/Stubs/CategorySelectionStub';
 import type { Script } from '@/domain/Executables/Script/Script';
+import { createExecutableIdFromNodeId } from '@/presentation/components/Scripts/View/Tree/TreeViewAdapter/CategoryNodeMetadataConverter';
 
 describe('CategoryReverter', () => {
   describe('getState', () => {
@@ -122,8 +122,8 @@ describe('CategoryReverter', () => {
     }) => {
       it(description, () => {
         // arrange
-        const category = new CategoryStub(1).withScripts(...allScripts);
-        const categoryNodeId = getCategoryNodeId(category);
+        const category = new CategoryStub('parent-category-id').withScripts(...allScripts);
+        const categoryNodeId = createExecutableIdFromNodeId(category.executableId);
         const collection = new CategoryCollectionStub().withAction(category);
         const categoryReverter = new CategoryReverter(categoryNodeId, collection);
         const selectedScripts = selectScripts(allScripts);
@@ -157,8 +157,8 @@ describe('CategoryReverter', () => {
           new ScriptStub('reversible').withReversibility(true),
           new ScriptStub('reversible2').withReversibility(true),
         ];
-        const category = new CategoryStub(1).withScripts(...allScripts);
-        const nodeId = getCategoryNodeId(category);
+        const category = new CategoryStub('parent-category').withScripts(...allScripts);
+        const nodeId = createExecutableIdFromNodeId(category.executableId);
         const collection = new CategoryCollectionStub().withAction(category);
         const categorySelection = new CategorySelectionStub();
         const categoryReverter = new CategoryReverter(nodeId, collection);
@@ -170,7 +170,7 @@ describe('CategoryReverter', () => {
         );
         // assert
         const actualRevertState = categorySelection.isCategorySelected(
-          category.id,
+          category.executableId,
           expectedRevertState,
         );
         expect(actualRevertState).to.equal(true);
diff --git a/tests/unit/presentation/components/Scripts/View/Tree/NodeContent/Reverter/ReverterFactory.spec.ts b/tests/unit/presentation/components/Scripts/View/Tree/NodeContent/Reverter/ReverterFactory.spec.ts
index aee90dbc..993b7610 100644
--- a/tests/unit/presentation/components/Scripts/View/Tree/NodeContent/Reverter/ReverterFactory.spec.ts
+++ b/tests/unit/presentation/components/Scripts/View/Tree/NodeContent/Reverter/ReverterFactory.spec.ts
@@ -5,15 +5,16 @@ import { CategoryReverter } from '@/presentation/components/Scripts/View/Tree/No
 import { CategoryCollectionStub } from '@tests/unit/shared/Stubs/CategoryCollectionStub';
 import { CategoryStub } from '@tests/unit/shared/Stubs/CategoryStub';
 import { ScriptStub } from '@tests/unit/shared/Stubs/ScriptStub';
-import { getCategoryNodeId, getScriptNodeId } from '@/presentation/components/Scripts/View/Tree/TreeViewAdapter/CategoryNodeMetadataConverter';
+import { createNodeIdForExecutable } from '@/presentation/components/Scripts/View/Tree/TreeViewAdapter/CategoryNodeMetadataConverter';
 import { type NodeMetadata, NodeType } from '@/presentation/components/Scripts/View/Tree/NodeContent/NodeMetadata';
+import type { TreeNodeId } from '@/presentation/components/Scripts/View/Tree/TreeView/Node/TreeNode';
 
 describe('ReverterFactory', () => {
   describe('getReverter', () => {
-    it('gets CategoryReverter for category node', () => {
+    it(`gets ${CategoryReverter.name} for category node`, () => {
       // arrange
-      const category = new CategoryStub(0).withScriptIds('55');
-      const node = getNodeContentStub(getCategoryNodeId(category), NodeType.Category);
+      const category = new CategoryStub('test-action-category').withScriptIds('55');
+      const node = getNodeContentStub(createNodeIdForExecutable(category), NodeType.Category);
       const collection = new CategoryCollectionStub()
         .withAction(category);
       // act
@@ -21,19 +22,19 @@ describe('ReverterFactory', () => {
       // assert
       expect(result instanceof CategoryReverter).to.equal(true);
     });
-    it('gets ScriptReverter for script node', () => {
+    it(`gets ${ScriptReverter.name} for script node`, () => {
       // arrange
       const script = new ScriptStub('test');
-      const node = getNodeContentStub(getScriptNodeId(script), NodeType.Script);
+      const node = getNodeContentStub(createNodeIdForExecutable(script), NodeType.Script);
       const collection = new CategoryCollectionStub()
-        .withAction(new CategoryStub(0).withScript(script));
+        .withAction(new CategoryStub('test-action-category').withScript(script));
       // act
       const result = getReverter(node, collection);
       // assert
       expect(result instanceof ScriptReverter).to.equal(true);
     });
   });
-  function getNodeContentStub(nodeId: string, type: NodeType): NodeMetadata {
+  function getNodeContentStub(nodeId: TreeNodeId, type: NodeType): NodeMetadata {
     return {
       id: nodeId,
       text: 'text',
diff --git a/tests/unit/presentation/components/Scripts/View/Tree/NodeContent/Reverter/ScriptReverter.spec.ts b/tests/unit/presentation/components/Scripts/View/Tree/NodeContent/Reverter/ScriptReverter.spec.ts
index 9a9e6bf9..10fd5bd9 100644
--- a/tests/unit/presentation/components/Scripts/View/Tree/NodeContent/Reverter/ScriptReverter.spec.ts
+++ b/tests/unit/presentation/components/Scripts/View/Tree/NodeContent/Reverter/ScriptReverter.spec.ts
@@ -2,7 +2,7 @@ import { describe, it, expect } from 'vitest';
 import { ScriptReverter } from '@/presentation/components/Scripts/View/Tree/NodeContent/Reverter/ScriptReverter';
 import { ScriptStub } from '@tests/unit/shared/Stubs/ScriptStub';
 import { SelectedScriptStub } from '@tests/unit/shared/Stubs/SelectedScriptStub';
-import { getScriptNodeId } from '@/presentation/components/Scripts/View/Tree/TreeViewAdapter/CategoryNodeMetadataConverter';
+import { createNodeIdForExecutable } from '@/presentation/components/Scripts/View/Tree/TreeViewAdapter/CategoryNodeMetadataConverter';
 import { UserSelectionStub } from '@tests/unit/shared/Stubs/UserSelectionStub';
 import type { SelectedScript } from '@/application/Context/State/Selection/Script/SelectedScript';
 import { ScriptSelectionStub } from '@tests/unit/shared/Stubs/ScriptSelectionStub';
@@ -11,7 +11,7 @@ describe('ScriptReverter', () => {
   describe('getState', () => {
     // arrange
     const script = new ScriptStub('id');
-    const nodeId = getScriptNodeId(script);
+    const nodeId = createNodeIdForExecutable(script);
     const testScenarios: ReadonlyArray<{
       readonly description: string;
       readonly selectedScripts: readonly SelectedScript[];
@@ -98,7 +98,7 @@ describe('ScriptReverter', () => {
         expectedRevert: false,
       },
     ];
-    const nodeId = getScriptNodeId(script);
+    const nodeId = createNodeIdForExecutable(script);
     testScenarios.forEach((
       { description, selection, expectedRevert },
     ) => {
@@ -111,7 +111,9 @@ describe('ScriptReverter', () => {
         // act
         sut.selectWithRevertState(revertState, userSelection);
         // assert
-        expect(scriptSelection.isScriptSelected(script.id, expectedRevert)).to.equal(true);
+        const isActuallySelected = scriptSelection
+          .isScriptSelected(script.executableId, expectedRevert);
+        expect(isActuallySelected).to.equal(true);
       });
     });
   });
diff --git a/tests/unit/presentation/components/Scripts/View/Tree/TreeView/Node/TreeNodeManager.spec.ts b/tests/unit/presentation/components/Scripts/View/Tree/TreeView/Node/TreeNodeManager.spec.ts
index 33b9284c..fd41f805 100644
--- a/tests/unit/presentation/components/Scripts/View/Tree/TreeView/Node/TreeNodeManager.spec.ts
+++ b/tests/unit/presentation/components/Scripts/View/Tree/TreeView/Node/TreeNodeManager.spec.ts
@@ -3,13 +3,14 @@ import { TreeNodeManager } from '@/presentation/components/Scripts/View/Tree/Tre
 import { itEachAbsentObjectValue, itEachAbsentStringValue } from '@tests/unit/shared/TestCases/AbsentTests';
 import { TreeNodeHierarchy } from '@/presentation/components/Scripts/View/Tree/TreeView/Node/Hierarchy/TreeNodeHierarchy';
 import { TreeNodeState } from '@/presentation/components/Scripts/View/Tree/TreeView/Node/State/TreeNodeState';
+import type { TreeNodeId } from '@/presentation/components/Scripts/View/Tree/TreeView/Node/TreeNode';
 
 describe('TreeNodeManager', () => {
   describe('constructor', () => {
     describe('id', () => {
       it('should initialize with the provided id', () => {
         // arrange
-        const expectedId = 'test-id';
+        const expectedId: TreeNodeId = 'test-id';
         // act
         const node = new TreeNodeManager(expectedId);
         // assert
@@ -18,9 +19,10 @@ describe('TreeNodeManager', () => {
       describe('should throw an error if id is not provided', () => {
         itEachAbsentStringValue((absentId) => {
           // arrange
+          const id = absentId as TreeNodeId;
           const expectedError = 'missing id';
           // act
-          const act = () => new TreeNodeManager(absentId);
+          const act = () => new TreeNodeManager(id);
           // assert
           expect(act).to.throw(expectedError);
         }, { excludeNull: true, excludeUndefined: true });
diff --git a/tests/unit/presentation/components/Scripts/View/Tree/TreeViewAdapter/CategoryNodeMetadataConverter.spec.ts b/tests/unit/presentation/components/Scripts/View/Tree/TreeViewAdapter/CategoryNodeMetadataConverter.spec.ts
index ec789135..4a060b51 100644
--- a/tests/unit/presentation/components/Scripts/View/Tree/TreeViewAdapter/CategoryNodeMetadataConverter.spec.ts
+++ b/tests/unit/presentation/components/Scripts/View/Tree/TreeViewAdapter/CategoryNodeMetadataConverter.spec.ts
@@ -5,31 +5,36 @@ import { CategoryStub } from '@tests/unit/shared/Stubs/CategoryStub';
 import { ScriptStub } from '@tests/unit/shared/Stubs/ScriptStub';
 import { CategoryCollectionStub } from '@tests/unit/shared/Stubs/CategoryCollectionStub';
 import {
-  getCategoryId, getCategoryNodeId, getScriptId,
-  getScriptNodeId, parseAllCategories, parseSingleCategory,
+  createExecutableIdFromNodeId,
+  createNodeIdForExecutable,
+  parseAllCategories,
+  parseSingleCategory,
 } from '@/presentation/components/Scripts/View/Tree/TreeViewAdapter/CategoryNodeMetadataConverter';
 import { ExecutableType } from '@/application/Parser/Executable/Validation/ExecutableType';
 import type { NodeMetadata } from '@/presentation/components/Scripts/View/Tree/NodeContent/NodeMetadata';
 import { expectExists } from '@tests/shared/Assertions/ExpectExists';
+import type { ExecutableId } from '@/domain/Executables/Identifiable';
 
 describe('CategoryNodeMetadataConverter', () => {
   it('can convert script id and back', () => {
     // arrange
-    const script = new ScriptStub('test');
+    const expectedScriptId: ExecutableId = 'expected-script-id';
+    const script = new ScriptStub(expectedScriptId);
     // act
-    const nodeId = getScriptNodeId(script);
-    const scriptId = getScriptId(nodeId);
+    const nodeId = createNodeIdForExecutable(script);
+    const actualScriptId = createExecutableIdFromNodeId(nodeId);
     // assert
-    expect(scriptId).to.equal(script.id);
+    expect(actualScriptId).to.equal(expectedScriptId);
   });
   it('can convert category id and back', () => {
     // arrange
-    const category = new CategoryStub(55);
+    const expectedCategoryId: ExecutableId = 'expected-category-id';
+    const category = new CategoryStub(expectedCategoryId);
     // act
-    const nodeId = getCategoryNodeId(category);
-    const scriptId = getCategoryId(nodeId);
+    const nodeId = createNodeIdForExecutable(category);
+    const actualCategoryId = createExecutableIdFromNodeId(nodeId);
     // assert
-    expect(scriptId).to.equal(category.id);
+    expect(actualCategoryId).to.equal(expectedCategoryId);
   });
   describe('parseSingleCategory', () => {
     it('throws error if parent category cannot be retrieved', () => {
@@ -38,32 +43,45 @@ describe('CategoryNodeMetadataConverter', () => {
       const collection = new CategoryCollectionStub();
       collection.getCategory = () => { throw new Error(expectedError); };
       // act
-      const act = () => parseSingleCategory(31, collection);
+      const act = () => parseSingleCategory('unimportant-id', collection);
       // assert
       expect(act).to.throw(expectedError);
     });
     it('can parse when category has sub categories', () => {
       // arrange
-      const categoryId = 31;
-      const firstSubCategory = new CategoryStub(11).withScriptIds('111', '112');
-      const secondSubCategory = new CategoryStub(categoryId)
-        .withCategory(new CategoryStub(33).withScriptIds('331', '331'))
-        .withCategory(new CategoryStub(44).withScriptIds('44'));
-      const collection = new CategoryCollectionStub().withAction(new CategoryStub(categoryId)
-        .withCategory(firstSubCategory)
-        .withCategory(secondSubCategory));
+      const parentCategoryId: ExecutableId = 'parent-category';
+      const firstSubcategory = new CategoryStub('subcategory-1')
+        .withScriptIds('subcategory-1-script-1', 'subcategory-1-script-2');
+      const secondSubCategory = new CategoryStub('subcategory-2')
+        .withCategory(
+          new CategoryStub('subcategory-2-subcategory-1')
+            .withScriptIds('subcategory-2-subcategory-1-script-1', 'subcategory-2-subcategory-1-script-2'),
+        )
+        .withCategory(
+          new CategoryStub('subcategory-2-subcategory-2')
+            .withScriptIds('subcategory-2-subcategory-2-script-1'),
+        );
+      const collection = new CategoryCollectionStub().withAction(
+        new CategoryStub(parentCategoryId)
+          .withCategory(firstSubcategory)
+          .withCategory(secondSubCategory),
+      );
       // act
-      const nodes = parseSingleCategory(categoryId, collection);
+      const nodes = parseSingleCategory(parentCategoryId, collection);
       // assert
       expectExists(nodes);
       expect(nodes).to.have.lengthOf(2);
-      expectSameCategory(nodes[0], firstSubCategory);
+      expectSameCategory(nodes[0], firstSubcategory);
       expectSameCategory(nodes[1], secondSubCategory);
     });
     it('can parse when category has sub scripts', () => {
       // arrange
-      const categoryId = 31;
-      const scripts = [new ScriptStub('script1'), new ScriptStub('script2'), new ScriptStub('script3')];
+      const categoryId: ExecutableId = 'expected-category-id';
+      const scripts: readonly Script[] = [
+        new ScriptStub('script1'),
+        new ScriptStub('script2'),
+        new ScriptStub('script3'),
+      ];
       const collection = new CategoryCollectionStub()
         .withAction(new CategoryStub(categoryId).withScripts(...scripts));
       // act
@@ -79,10 +97,11 @@ describe('CategoryNodeMetadataConverter', () => {
   it('parseAllCategories parses as expected', () => {
     // arrange
     const collection = new CategoryCollectionStub()
-      .withAction(new CategoryStub(0).withScriptIds('1, 2'))
-      .withAction(new CategoryStub(1).withCategories(
-        new CategoryStub(3).withScriptIds('3', '4'),
-        new CategoryStub(4).withCategory(new CategoryStub(5).withScriptIds('6')),
+      .withAction(new CategoryStub('category-1').withScriptIds('1, 2'))
+      .withAction(new CategoryStub('category-2').withCategories(
+        new CategoryStub('category-2-subcategory-1').withScriptIds('3', '4'),
+        new CategoryStub('category-2-subcategory-1')
+          .withCategory(new CategoryStub('category-2-subcategory-1-subcategory-1').withScriptIds('6')),
       ));
     // act
     const nodes = parseAllCategories(collection);
@@ -100,8 +119,8 @@ function isReversible(category: Category): boolean {
       return false;
     }
   }
-  if (category.subCategories) {
-    if (category.subCategories.some((c) => !isReversible(c))) {
+  if (category.subcategories) {
+    if (category.subcategories.some((c) => !isReversible(c))) {
       return false;
     }
   }
@@ -110,17 +129,17 @@ function isReversible(category: Category): boolean {
 
 function expectSameCategory(node: NodeMetadata, category: Category): void {
   expect(node.type).to.equal(ExecutableType.Category, getErrorMessage('type'));
-  expect(node.id).to.equal(getCategoryNodeId(category), getErrorMessage('id'));
+  expect(node.id).to.equal(createNodeIdForExecutable(category), getErrorMessage('id'));
   expect(node.docs).to.equal(category.docs, getErrorMessage('docs'));
   expect(node.text).to.equal(category.name, getErrorMessage('name'));
   expect(node.isReversible).to.equal(isReversible(category), getErrorMessage('isReversible'));
   expect(node.children).to.have.lengthOf(
-    category.scripts.length + category.subCategories.length,
+    category.scripts.length + category.subcategories.length,
     getErrorMessage('total children'),
   );
-  if (category.subCategories) {
-    for (let i = 0; i < category.subCategories.length; i++) {
-      expectSameCategory(node.children[i], category.subCategories[i]);
+  if (category.subcategories) {
+    for (let i = 0; i < category.subcategories.length; i++) {
+      expectSameCategory(node.children[i], category.subcategories[i]);
     }
   }
   if (category.scripts) {
@@ -137,7 +156,7 @@ function expectSameCategory(node: NodeMetadata, category: Category): void {
 
 function expectSameScript(node: NodeMetadata, script: Script): void {
   expect(node.type).to.equal(ExecutableType.Script, getErrorMessage('type'));
-  expect(node.id).to.equal(getScriptNodeId(script), getErrorMessage('id'));
+  expect(node.id).to.equal(createNodeIdForExecutable(script), getErrorMessage('id'));
   expect(node.docs).to.equal(script.docs, getErrorMessage('docs'));
   expect(node.text).to.equal(script.name, getErrorMessage('name'));
   expect(node.isReversible).to.equal(script.canRevert(), getErrorMessage('canRevert'));
diff --git a/tests/unit/presentation/components/Scripts/View/Tree/TreeViewAdapter/UseSelectedScriptNodeIds.spec.ts b/tests/unit/presentation/components/Scripts/View/Tree/TreeViewAdapter/UseSelectedScriptNodeIds.spec.ts
index 554d1260..8db64c9f 100644
--- a/tests/unit/presentation/components/Scripts/View/Tree/TreeViewAdapter/UseSelectedScriptNodeIds.spec.ts
+++ b/tests/unit/presentation/components/Scripts/View/Tree/TreeViewAdapter/UseSelectedScriptNodeIds.spec.ts
@@ -1,10 +1,12 @@
 import { describe, it, expect } from 'vitest';
 import { useSelectedScriptNodeIds } from '@/presentation/components/Scripts/View/Tree/TreeViewAdapter/UseSelectedScriptNodeIds';
 import { SelectedScriptStub } from '@tests/unit/shared/Stubs/SelectedScriptStub';
-import { getScriptNodeId } from '@/presentation/components/Scripts/View/Tree/TreeViewAdapter/CategoryNodeMetadataConverter';
+import { createNodeIdForExecutable } from '@/presentation/components/Scripts/View/Tree/TreeViewAdapter/CategoryNodeMetadataConverter';
 import type { Script } from '@/domain/Executables/Script/Script';
 import { UseUserSelectionStateStub } from '@tests/unit/shared/Stubs/UseUserSelectionStateStub';
 import { ScriptStub } from '@tests/unit/shared/Stubs/ScriptStub';
+import type { TreeNodeId } from '@/presentation/components/Scripts/View/Tree/TreeView/Node/TreeNode';
+import type { Executable } from '@/domain/Executables/Executable';
 
 describe('useSelectedScriptNodeIds', () => {
   it('returns an empty array when no scripts are selected', () => {
@@ -23,7 +25,7 @@ describe('useSelectedScriptNodeIds', () => {
         new SelectedScriptStub(new ScriptStub('id-1')),
         new SelectedScriptStub(new ScriptStub('id-2')),
       ];
-      const parsedNodeIds = new Map<Script, string>([
+      const parsedNodeIds = new Map<Script, TreeNodeId>([
         [selectedScripts[0].script, 'expected-id-1'],
         [selectedScripts[1].script, 'expected-id-2'],
       ]);
@@ -47,7 +49,7 @@ describe('useSelectedScriptNodeIds', () => {
         new SelectedScriptStub(new ScriptStub('id-1')),
         new SelectedScriptStub(new ScriptStub('id-2')),
       ];
-      const parsedNodeIds = new Map<Script, string>([
+      const parsedNodeIds = new Map<Script, TreeNodeId>([
         [changedScripts[0].script, 'expected-id-1'],
         [changedScripts[1].script, 'expected-id-2'],
       ]);
@@ -68,9 +70,9 @@ describe('useSelectedScriptNodeIds', () => {
   });
 });
 
-type ScriptNodeIdParser = typeof getScriptNodeId;
+type NodeIdParser = typeof createNodeIdForExecutable;
 
-function createNodeIdParserFromMap(scriptToIdMap: Map<Script, string>): ScriptNodeIdParser {
+function createNodeIdParserFromMap(scriptToIdMap: Map<Executable, TreeNodeId>): NodeIdParser {
   return (script) => {
     const expectedId = scriptToIdMap.get(script);
     if (!expectedId) {
@@ -81,12 +83,12 @@ function createNodeIdParserFromMap(scriptToIdMap: Map<Script, string>): ScriptNo
 }
 
 function runHook(scenario?: {
-  readonly scriptNodeIdParser?: ScriptNodeIdParser,
+  readonly scriptNodeIdParser?: NodeIdParser,
   readonly useSelectionState?: UseUserSelectionStateStub,
 }) {
   const useSelectionStateStub = scenario?.useSelectionState ?? new UseUserSelectionStateStub();
-  const nodeIdParser: ScriptNodeIdParser = scenario?.scriptNodeIdParser
-    ?? ((script) => script.id);
+  const nodeIdParser: NodeIdParser = scenario?.scriptNodeIdParser
+    ?? ((script) => script.executableId);
   const returnObject = useSelectedScriptNodeIds(useSelectionStateStub.get(), nodeIdParser);
   return {
     returnObject,
diff --git a/tests/unit/presentation/components/Scripts/View/Tree/TreeViewAdapter/UseTreeViewFilterEvent.spec.ts b/tests/unit/presentation/components/Scripts/View/Tree/TreeViewAdapter/UseTreeViewFilterEvent.spec.ts
index bb7b16d9..8a6028f6 100644
--- a/tests/unit/presentation/components/Scripts/View/Tree/TreeViewAdapter/UseTreeViewFilterEvent.spec.ts
+++ b/tests/unit/presentation/components/Scripts/View/Tree/TreeViewAdapter/UseTreeViewFilterEvent.spec.ts
@@ -216,29 +216,29 @@ function itExpectedFilterTriggeredEvent(
     {
       description: 'returns true when category exists',
       scriptMatches: [],
-      categoryMatches: [new CategoryStub(1)],
-      givenNode: createNode({ id: '1', hasParent: false }),
+      categoryMatches: [new CategoryStub('category-match-1')],
+      givenNode: createNode({ id: 'category-match-1', hasParent: false }),
       expectedPredicateResult: true,
     },
     {
       description: 'returns true when script exists',
-      scriptMatches: [new ScriptStub('a')],
+      scriptMatches: [new ScriptStub('script-match-1')],
       categoryMatches: [],
-      givenNode: createNode({ id: 'a', hasParent: true }),
+      givenNode: createNode({ id: 'script-match-1', hasParent: true }),
       expectedPredicateResult: true,
     },
     {
       description: 'returns false when category is missing',
-      scriptMatches: [new ScriptStub('b')],
-      categoryMatches: [new CategoryStub(2)],
-      givenNode: createNode({ id: '1', hasParent: false }),
+      scriptMatches: [new ScriptStub('script-match-1')],
+      categoryMatches: [new CategoryStub('category-match-1')],
+      givenNode: createNode({ id: 'unrelated-node', hasParent: false }),
       expectedPredicateResult: false,
     },
     {
       description: 'finds false when script is missing',
-      scriptMatches: [new ScriptStub('b')],
-      categoryMatches: [new CategoryStub(1)],
-      givenNode: createNode({ id: 'a', hasParent: true }),
+      scriptMatches: [new ScriptStub('script-match-1')],
+      categoryMatches: [new CategoryStub('category-match-1')],
+      givenNode: createNode({ id: 'unrelated-node', hasParent: true }),
       expectedPredicateResult: false,
     },
   ];
@@ -261,8 +261,8 @@ function itExpectedFilterTriggeredEvent(
       expect(event.value.predicate).toBeDefined();
       const actualPredicateResult = event.value.predicate(givenNode);
       expect(actualPredicateResult).to.equal(expectedPredicateResult, formatAssertionMessage([
-        `Script matches (${scriptMatches.length}): [${scriptMatches.map((s) => s.id).join(', ')}]`,
-        `Category matches (${categoryMatches.length}): [${categoryMatches.map((s) => s.id).join(', ')}]`,
+        `Script matches (${scriptMatches.length}): [${scriptMatches.map((s) => s.executableId).join(', ')}]`,
+        `Category matches (${categoryMatches.length}): [${categoryMatches.map((s) => s.executableId).join(', ')}]`,
         `Expected node: "${givenNode.id}"`,
       ]));
     });
diff --git a/tests/unit/presentation/components/Scripts/View/Tree/TreeViewAdapter/UseTreeViewNodeInput.spec.ts b/tests/unit/presentation/components/Scripts/View/Tree/TreeViewAdapter/UseTreeViewNodeInput.spec.ts
index 3739ab71..3dcfce8c 100644
--- a/tests/unit/presentation/components/Scripts/View/Tree/TreeViewAdapter/UseTreeViewNodeInput.spec.ts
+++ b/tests/unit/presentation/components/Scripts/View/Tree/TreeViewAdapter/UseTreeViewNodeInput.spec.ts
@@ -7,21 +7,22 @@ import { CategoryCollectionStateStub } from '@tests/unit/shared/Stubs/CategoryCo
 import { UseCollectionStateStub } from '@tests/unit/shared/Stubs/UseCollectionStateStub';
 import { CategoryCollectionStub } from '@tests/unit/shared/Stubs/CategoryCollectionStub';
 import { CategoryStub } from '@tests/unit/shared/Stubs/CategoryStub';
-import type { ICategoryCollection } from '@/domain/ICategoryCollection';
+import type { ICategoryCollection } from '@/domain/Collection/ICategoryCollection';
 import type { NodeMetadata } from '@/presentation/components/Scripts/View/Tree/NodeContent/NodeMetadata';
 import { NodeMetadataStub } from '@tests/unit/shared/Stubs/NodeMetadataStub';
 import { convertToNodeInput } from '@/presentation/components/Scripts/View/Tree/TreeViewAdapter/TreeNodeMetadataConverter';
 import { TreeInputNodeDataStub as TreeInputNodeData, TreeInputNodeDataStub } from '@tests/unit/shared/Stubs/TreeInputNodeDataStub';
+import type { ExecutableId } from '@/domain/Executables/Identifiable';
 
 describe('useTreeViewNodeInput', () => {
   describe('when given categoryId', () => {
     it('sets input nodes correctly', async () => {
       // arrange
-      const testCategoryIdRef = ref<number | undefined>();
+      const testCategoryIdRef = ref<ExecutableId | undefined>();
       const {
         useStateStub, returnObject, parserMock, converterMock,
       } = mountWrapperComponent(testCategoryIdRef);
-      const expectedCategoryId = 123;
+      const expectedCategoryId: ExecutableId = 'expected-category-id';
       const expectedCategoryCollection = new CategoryCollectionStub().withAction(
         new CategoryStub(expectedCategoryId),
       );
@@ -55,12 +56,12 @@ describe('useTreeViewNodeInput', () => {
   describe('when not given a categoryId', () => {
     it('sets input nodes correctly', () => {
       // arrange
-      const testCategoryId = ref<number | undefined>();
+      const testCategoryId = ref<ExecutableId | undefined>();
       const {
         useStateStub, returnObject, parserMock, converterMock,
       } = mountWrapperComponent(testCategoryId);
       const expectedCategoryCollection = new CategoryCollectionStub().withAction(
-        new CategoryStub(123),
+        new CategoryStub('expected-action-category'),
       );
       const expectedMetadata = [new NodeMetadataStub(), new NodeMetadataStub()];
       parserMock.setupParseAllScenario({
@@ -88,7 +89,7 @@ describe('useTreeViewNodeInput', () => {
   });
 });
 
-function mountWrapperComponent(categoryIdRef: Ref<number | undefined>) {
+function mountWrapperComponent(categoryIdRef: Ref<ExecutableId | undefined>) {
   const useStateStub = new UseCollectionStateStub();
   const parserMock = mockCategoryNodeParser();
   const converterMock = mockConverter();
@@ -146,7 +147,7 @@ function mockConverter() {
 }
 
 interface ParseSingleScenario {
-  readonly givenId: number;
+  readonly givenId: ExecutableId;
   readonly givenCollection: ICategoryCollection;
   readonly parseResult: NodeMetadata[];
 }
diff --git a/tests/unit/shared/Stubs/ApplicationStub.ts b/tests/unit/shared/Stubs/ApplicationStub.ts
index e87c6cba..380cb2b8 100644
--- a/tests/unit/shared/Stubs/ApplicationStub.ts
+++ b/tests/unit/shared/Stubs/ApplicationStub.ts
@@ -1,5 +1,5 @@
 import type { IApplication } from '@/domain/IApplication';
-import type { ICategoryCollection } from '@/domain/ICategoryCollection';
+import type { ICategoryCollection } from '@/domain/Collection/ICategoryCollection';
 import { OperatingSystem } from '@/domain/OperatingSystem';
 import type { ProjectDetails } from '@/domain/Project/ProjectDetails';
 import { ProjectDetailsStub } from './ProjectDetailsStub';
diff --git a/tests/unit/shared/Stubs/CategoryCollectionFactoryStub.ts b/tests/unit/shared/Stubs/CategoryCollectionFactoryStub.ts
index ee22b72b..3c8c48e9 100644
--- a/tests/unit/shared/Stubs/CategoryCollectionFactoryStub.ts
+++ b/tests/unit/shared/Stubs/CategoryCollectionFactoryStub.ts
@@ -1,6 +1,6 @@
 import type { CategoryCollectionFactory } from '@/application/Parser/CategoryCollectionParser';
-import type { CategoryCollectionInitParameters } from '@/domain/CategoryCollection';
-import type { ICategoryCollection } from '@/domain/ICategoryCollection';
+import type { CategoryCollectionInitParameters } from '@/domain/Collection/CategoryCollection';
+import type { ICategoryCollection } from '@/domain/Collection/ICategoryCollection';
 import { CategoryCollectionStub } from './CategoryCollectionStub';
 
 export function createCategoryCollectionFactorySpy(): {
diff --git a/tests/unit/shared/Stubs/CategoryCollectionParserStub.ts b/tests/unit/shared/Stubs/CategoryCollectionParserStub.ts
index 436ed9c9..41afb129 100644
--- a/tests/unit/shared/Stubs/CategoryCollectionParserStub.ts
+++ b/tests/unit/shared/Stubs/CategoryCollectionParserStub.ts
@@ -1,5 +1,5 @@
 import type { ProjectDetails } from '@/domain/Project/ProjectDetails';
-import type { ICategoryCollection } from '@/domain/ICategoryCollection';
+import type { ICategoryCollection } from '@/domain/Collection/ICategoryCollection';
 import { getEnumValues } from '@/application/Common/Enum';
 import type { CollectionData } from '@/application/collections/';
 import { OperatingSystem } from '@/domain/OperatingSystem';
diff --git a/tests/unit/shared/Stubs/CategoryCollectionStateStub.ts b/tests/unit/shared/Stubs/CategoryCollectionStateStub.ts
index fc8cc4e6..0a99fd68 100644
--- a/tests/unit/shared/Stubs/CategoryCollectionStateStub.ts
+++ b/tests/unit/shared/Stubs/CategoryCollectionStateStub.ts
@@ -3,7 +3,7 @@ import type { ICategoryCollectionState } from '@/application/Context/State/ICate
 import { OperatingSystem } from '@/domain/OperatingSystem';
 import type { Script } from '@/domain/Executables/Script/Script';
 import { ScriptStub } from '@tests/unit/shared/Stubs/ScriptStub';
-import type { ICategoryCollection } from '@/domain/ICategoryCollection';
+import type { ICategoryCollection } from '@/domain/Collection/ICategoryCollection';
 import type { UserSelection } from '@/application/Context/State/Selection/UserSelection';
 import type { SelectedScript } from '@/application/Context/State/Selection/Script/SelectedScript';
 import type { FilterContext } from '@/application/Context/State/Filter/FilterContext';
@@ -33,7 +33,10 @@ export class CategoryCollectionStateStub implements ICategoryCollectionState {
     this.collection = new CategoryCollectionStub()
       .withOs(this.os)
       .withTotalScripts(this.allScripts.length)
-      .withAction(new CategoryStub(0).withScripts(...allScripts));
+      .withAction(
+        new CategoryStub(`[${CategoryCollectionStateStub.name}]-default-action`)
+          .withScripts(...allScripts),
+      );
   }
 
   public withCollection(collection: ICategoryCollection): this {
diff --git a/tests/unit/shared/Stubs/CategoryCollectionStub.ts b/tests/unit/shared/Stubs/CategoryCollectionStub.ts
index 548d79e8..27f468ce 100644
--- a/tests/unit/shared/Stubs/CategoryCollectionStub.ts
+++ b/tests/unit/shared/Stubs/CategoryCollectionStub.ts
@@ -2,8 +2,9 @@ import { OperatingSystem } from '@/domain/OperatingSystem';
 import type { IScriptingDefinition } from '@/domain/IScriptingDefinition';
 import type { Script } from '@/domain/Executables/Script/Script';
 import type { Category } from '@/domain/Executables/Category/Category';
-import type { ICategoryCollection } from '@/domain/ICategoryCollection';
+import type { ICategoryCollection } from '@/domain/Collection/ICategoryCollection';
 import { RecommendationLevel } from '@/domain/Executables/Script/RecommendationLevel';
+import type { ExecutableId } from '@/domain/Executables/Identifiable';
 import { ScriptStub } from './ScriptStub';
 import { ScriptingDefinitionStub } from './ScriptingDefinitionStub';
 import { CategoryStub } from './CategoryStub';
@@ -22,9 +23,9 @@ export class CategoryCollectionStub implements ICategoryCollection {
   public readonly actions = new Array<Category>();
 
   public withSomeActions(): this {
-    this.withAction(new CategoryStub(1));
-    this.withAction(new CategoryStub(2));
-    this.withAction(new CategoryStub(3));
+    this.withAction(new CategoryStub(`[${CategoryCollectionStub}]-action-1`));
+    this.withAction(new CategoryStub(`[${CategoryCollectionStub}]-action-2`));
+    this.withAction(new CategoryStub(`[${CategoryCollectionStub}]-action-3`));
     return this;
   }
 
@@ -60,9 +61,9 @@ export class CategoryCollectionStub implements ICategoryCollection {
     return this;
   }
 
-  public getCategory(categoryId: number): Category {
+  public getCategory(categoryId: ExecutableId): Category {
     return this.getAllCategories()
-      .find((category) => category.id === categoryId)
+      .find((category) => category.executableId === categoryId)
       ?? new CategoryStub(categoryId);
   }
 
@@ -73,7 +74,7 @@ export class CategoryCollectionStub implements ICategoryCollection {
 
   public getScript(scriptId: string): Script {
     return this.getAllScripts()
-      .find((script) => scriptId === script.id)
+      .find((script) => scriptId === script.executableId)
       ?? new ScriptStub(scriptId);
   }
 
@@ -89,7 +90,7 @@ export class CategoryCollectionStub implements ICategoryCollection {
 }
 
 function getSubCategoriesRecursively(category: Category): ReadonlyArray<Category> {
-  return (category.subCategories || []).flatMap(
+  return (category.subcategories || []).flatMap(
     (subCategory) => [subCategory, ...getSubCategoriesRecursively(subCategory)],
   );
 }
@@ -97,7 +98,7 @@ function getSubCategoriesRecursively(category: Category): ReadonlyArray<Category
 function getScriptsRecursively(category: Category): ReadonlyArray<Script> {
   return [
     ...(category.scripts || []),
-    ...(category.subCategories || []).flatMap(
+    ...(category.subcategories || []).flatMap(
       (subCategory) => getScriptsRecursively(subCategory),
     ),
   ];
diff --git a/tests/unit/shared/Stubs/CategoryCollectionValidationContextStub.ts b/tests/unit/shared/Stubs/CategoryCollectionValidationContextStub.ts
new file mode 100644
index 00000000..c4bba9ed
--- /dev/null
+++ b/tests/unit/shared/Stubs/CategoryCollectionValidationContextStub.ts
@@ -0,0 +1,34 @@
+import type { CategoryCollectionValidationContext } from '@/domain/Collection/Validation/CategoryCollectionValidator';
+import type { Category } from '@/domain/Executables/Category/Category';
+import type { Script } from '@/domain/Executables/Script/Script';
+import { OperatingSystem } from '@/domain/OperatingSystem';
+import { CategoryStub } from './CategoryStub';
+import { ScriptStub } from './ScriptStub';
+
+export class CategoryCollectionValidationContextStub
+implements CategoryCollectionValidationContext {
+  public allScripts: readonly Script[] = [
+    new ScriptStub(`[${CategoryCollectionValidationContextStub.name}] test-script`),
+  ];
+
+  public allCategories: readonly Category[] = [
+    new CategoryStub(`[${CategoryCollectionValidationContextStub.name}] test-category`),
+  ];
+
+  public operatingSystem: OperatingSystem = OperatingSystem.iPadOS;
+
+  public withOperatingSystem(operatingSystem: OperatingSystem): this {
+    this.operatingSystem = operatingSystem;
+    return this;
+  }
+
+  public withAllCategories(allCategories: readonly Category[]): this {
+    this.allCategories = allCategories;
+    return this;
+  }
+
+  public withAllScripts(allScripts: readonly Script[]): this {
+    this.allScripts = allScripts;
+    return this;
+  }
+}
diff --git a/tests/unit/shared/Stubs/CategoryFactoryStub.ts b/tests/unit/shared/Stubs/CategoryFactoryStub.ts
index 010de32f..098cc10e 100644
--- a/tests/unit/shared/Stubs/CategoryFactoryStub.ts
+++ b/tests/unit/shared/Stubs/CategoryFactoryStub.ts
@@ -1,6 +1,5 @@
-import type { CategoryFactory } from '@/application/Parser/Executable/CategoryParser';
-import type { CategoryInitParameters } from '@/domain/Executables/Category/CollectionCategory';
 import type { Category } from '@/domain/Executables/Category/Category';
+import type { CategoryFactory, CategoryInitParameters } from '@/domain/Executables/Category/CategoryFactory';
 import { CategoryStub } from './CategoryStub';
 
 export function createCategoryFactorySpy(): {
@@ -10,7 +9,7 @@ export function createCategoryFactorySpy(): {
   const createdCategories = new Map<Category, CategoryInitParameters>();
   return {
     categoryFactorySpy: (parameters) => {
-      const category = new CategoryStub(55);
+      const category = new CategoryStub('category-from-factory-stub');
       createdCategories.set(category, parameters);
       return category;
     },
diff --git a/tests/unit/shared/Stubs/CategoryParserStub.ts b/tests/unit/shared/Stubs/CategoryParserStub.ts
index ce41b016..d5b83be9 100644
--- a/tests/unit/shared/Stubs/CategoryParserStub.ts
+++ b/tests/unit/shared/Stubs/CategoryParserStub.ts
@@ -16,7 +16,7 @@ export class CategoryParserStub {
       if (result) {
         return result;
       }
-      return new CategoryStub(5489);
+      return new CategoryStub(`[${CategoryParserStub.name}]-parsed-category`);
     };
   }
 
diff --git a/tests/unit/shared/Stubs/CategorySelectionStub.ts b/tests/unit/shared/Stubs/CategorySelectionStub.ts
index 43a5574d..84e4a106 100644
--- a/tests/unit/shared/Stubs/CategorySelectionStub.ts
+++ b/tests/unit/shared/Stubs/CategorySelectionStub.ts
@@ -1,11 +1,12 @@
 import type { CategorySelection } from '@/application/Context/State/Selection/Category/CategorySelection';
 import type { CategorySelectionChangeCommand } from '@/application/Context/State/Selection/Category/CategorySelectionChange';
+import type { ExecutableId } from '@/domain/Executables/Identifiable';
 import { StubWithObservableMethodCalls } from './StubWithObservableMethodCalls';
 
 export class CategorySelectionStub
   extends StubWithObservableMethodCalls<CategorySelection>
   implements CategorySelection {
-  public isCategorySelected(categoryId: number, revert: boolean): boolean {
+  public isCategorySelected(categoryId: ExecutableId, revert: boolean): boolean {
     const call = this.callHistory.find(
       (c) => c.methodName === 'processChanges'
       && c.args[0].changes.some((change) => (
diff --git a/tests/unit/shared/Stubs/CategoryStub.ts b/tests/unit/shared/Stubs/CategoryStub.ts
index fe67c92c..a3503dab 100644
--- a/tests/unit/shared/Stubs/CategoryStub.ts
+++ b/tests/unit/shared/Stubs/CategoryStub.ts
@@ -1,13 +1,13 @@
-import { BaseEntity } from '@/infrastructure/Entity/BaseEntity';
 import type { Category } from '@/domain/Executables/Category/Category';
 import { RecommendationLevel } from '@/domain/Executables/Script/RecommendationLevel';
 import type { Script } from '@/domain/Executables/Script/Script';
+import type { ExecutableId } from '@/domain/Executables/Identifiable';
 import { ScriptStub } from './ScriptStub';
 
-export class CategoryStub extends BaseEntity<number> implements Category {
-  public name = `category-with-id-${this.id}`;
+export class CategoryStub implements Category {
+  public name = `[${CategoryStub.name}] name (ID: ${this.executableId})`;
 
-  public readonly subCategories = new Array<Category>();
+  public readonly subcategories = new Array<Category>();
 
   public readonly scripts = new Array<Script>();
 
@@ -15,25 +15,25 @@ export class CategoryStub extends BaseEntity<number> implements Category {
 
   private allScriptsRecursively: (readonly Script[]) | undefined;
 
-  public constructor(id: number) {
-    super(id);
-  }
+  public constructor(
+    readonly executableId: ExecutableId,
+  ) { }
 
   public includes(script: Script): boolean {
-    return this.getAllScriptsRecursively().some((s) => s.id === script.id);
+    return this.getAllScriptsRecursively().some((s) => s.executableId === script.executableId);
   }
 
   public getAllScriptsRecursively(): readonly Script[] {
     if (this.allScriptsRecursively === undefined) {
       return [
         ...this.scripts,
-        ...this.subCategories.flatMap((c) => c.getAllScriptsRecursively()),
+        ...this.subcategories.flatMap((c) => c.getAllScriptsRecursively()),
       ];
     }
     return this.allScriptsRecursively;
   }
 
-  public withScriptIds(...scriptIds: readonly string[]): this {
+  public withScriptIds(...scriptIds: readonly ExecutableId[]): this {
     return this.withScripts(
       ...scriptIds.map((id) => new ScriptStub(id)),
     );
@@ -70,7 +70,7 @@ export class CategoryStub extends BaseEntity<number> implements Category {
   }
 
   public withCategory(category: Category): this {
-    this.subCategories.push(category);
+    this.subcategories.push(category);
     return this;
   }
 
diff --git a/tests/unit/shared/Stubs/FilterResultStub.ts b/tests/unit/shared/Stubs/FilterResultStub.ts
index 59c3b4d7..e7144390 100644
--- a/tests/unit/shared/Stubs/FilterResultStub.ts
+++ b/tests/unit/shared/Stubs/FilterResultStub.ts
@@ -19,8 +19,13 @@ export class FilterResultStub implements FilterResult {
 
   public withSomeMatches() {
     return this
-      .withCategoryMatches([new CategoryStub(3).withScriptIds('script-1')])
-      .withScriptMatches([new ScriptStub('script-2')]);
+      .withCategoryMatches([
+        new CategoryStub(`[${FilterResultStub.name}]-matched-category-1`)
+          .withScriptIds(`[${FilterResultStub.name}]-matched-script-1`),
+      ])
+      .withScriptMatches([
+        new ScriptStub(`[${FilterResultStub.name}]-matched-script-2`),
+      ]);
   }
 
   public withCategoryMatches(matches: readonly Category[]) {
diff --git a/tests/unit/shared/Stubs/FilterStrategyStub.ts b/tests/unit/shared/Stubs/FilterStrategyStub.ts
index 38f03143..4bb62e09 100644
--- a/tests/unit/shared/Stubs/FilterStrategyStub.ts
+++ b/tests/unit/shared/Stubs/FilterStrategyStub.ts
@@ -1,6 +1,6 @@
 import type { FilterResult } from '@/application/Context/State/Filter/Result/FilterResult';
 import type { FilterStrategy } from '@/application/Context/State/Filter/Strategy/FilterStrategy';
-import type { ICategoryCollection } from '@/domain/ICategoryCollection';
+import type { ICategoryCollection } from '@/domain/Collection/ICategoryCollection';
 import { FilterResultStub } from './FilterResultStub';
 import { StubWithObservableMethodCalls } from './StubWithObservableMethodCalls';
 
diff --git a/tests/unit/shared/Stubs/NumericEntityStub.ts b/tests/unit/shared/Stubs/NumericEntityStub.ts
deleted file mode 100644
index b3bc4bf1..00000000
--- a/tests/unit/shared/Stubs/NumericEntityStub.ts
+++ /dev/null
@@ -1,14 +0,0 @@
-import { BaseEntity } from '@/infrastructure/Entity/BaseEntity';
-
-export class NumericEntityStub extends BaseEntity<number> {
-  public customProperty = 'customProperty';
-
-  public constructor(id: number) {
-    super(id);
-  }
-
-  public withCustomProperty(value: string): NumericEntityStub {
-    this.customProperty = value;
-    return this;
-  }
-}
diff --git a/tests/unit/shared/Stubs/RepositoryEntityStub.ts b/tests/unit/shared/Stubs/RepositoryEntityStub.ts
new file mode 100644
index 00000000..caa97d3b
--- /dev/null
+++ b/tests/unit/shared/Stubs/RepositoryEntityStub.ts
@@ -0,0 +1,14 @@
+import type { RepositoryEntity, RepositoryEntityId } from '@/application/Repository/RepositoryEntity';
+
+export class RepositoryEntityStub implements RepositoryEntity {
+  public customProperty = 'customProperty';
+
+  public constructor(
+    public readonly id: RepositoryEntityId,
+  ) { }
+
+  public withCustomPropertyValue(value: string): RepositoryEntityStub {
+    this.customProperty = value;
+    return this;
+  }
+}
diff --git a/tests/unit/shared/Stubs/ScriptFactoryStub.ts b/tests/unit/shared/Stubs/ScriptFactoryStub.ts
index 7fe0c310..8275d4fe 100644
--- a/tests/unit/shared/Stubs/ScriptFactoryStub.ts
+++ b/tests/unit/shared/Stubs/ScriptFactoryStub.ts
@@ -1,6 +1,5 @@
-import type { ScriptFactory } from '@/application/Parser/Executable/Script/ScriptParser';
 import type { Script } from '@/domain/Executables/Script/Script';
-import type { ScriptInitParameters } from '@/domain/Executables/Script/CollectionScript';
+import type { ScriptFactory, ScriptInitParameters } from '@/domain/Executables/Script/ScriptFactory';
 import { ScriptStub } from './ScriptStub';
 
 export function createScriptFactorySpy(): {
diff --git a/tests/unit/shared/Stubs/ScriptStub.ts b/tests/unit/shared/Stubs/ScriptStub.ts
index 4c447d27..6997da01 100644
--- a/tests/unit/shared/Stubs/ScriptStub.ts
+++ b/tests/unit/shared/Stubs/ScriptStub.ts
@@ -1,15 +1,15 @@
-import { BaseEntity } from '@/infrastructure/Entity/BaseEntity';
 import type { Script } from '@/domain/Executables/Script/Script';
 import { RecommendationLevel } from '@/domain/Executables/Script/RecommendationLevel';
 import type { ScriptCode } from '@/domain/Executables/Script/Code/ScriptCode';
+import type { ExecutableId } from '@/domain/Executables/Identifiable';
 import { SelectedScriptStub } from './SelectedScriptStub';
 
-export class ScriptStub extends BaseEntity<string> implements Script {
-  public name = `name${this.id}`;
+export class ScriptStub implements Script {
+  public name = `name${this.executableId}`;
 
   public code: ScriptCode = {
-    execute: `REM execute-code (${this.id})`,
-    revert: `REM revert-code (${this.id})`,
+    execute: `REM execute-code (${this.executableId})`,
+    revert: `REM revert-code (${this.executableId})`,
   };
 
   public docs: readonly string[] = new Array<string>();
@@ -18,9 +18,7 @@ export class ScriptStub extends BaseEntity<string> implements Script {
 
   private isReversible: boolean | undefined = undefined;
 
-  constructor(public readonly id: string) {
-    super(id);
-  }
+  constructor(public readonly executableId: ExecutableId) { }
 
   public canRevert(): boolean {
     if (this.isReversible === undefined) {
diff --git a/tests/unit/shared/Stubs/SelectedScriptStub.ts b/tests/unit/shared/Stubs/SelectedScriptStub.ts
index 175859e8..e077ceff 100644
--- a/tests/unit/shared/Stubs/SelectedScriptStub.ts
+++ b/tests/unit/shared/Stubs/SelectedScriptStub.ts
@@ -1,17 +1,18 @@
 import type { SelectedScript } from '@/application/Context/State/Selection/Script/SelectedScript';
+import type { RepositoryEntityId } from '@/application/Repository/RepositoryEntity';
 import type { Script } from '@/domain/Executables/Script/Script';
 
 export class SelectedScriptStub implements SelectedScript {
   public readonly script: Script;
 
-  public readonly id: string;
+  public readonly id: RepositoryEntityId;
 
   public revert: boolean;
 
   constructor(
     script: Script,
   ) {
-    this.id = script.id;
+    this.id = script.executableId;
     this.script = script;
   }