diff --git a/bin-saphe/depsConfig.ml b/bin-saphe/depsConfig.ml
index e08bf66b8..037803af2 100644
--- a/bin-saphe/depsConfig.ml
+++ b/bin-saphe/depsConfig.ml
@@ -1,4 +1,8 @@
 
+open MyUtil
+open ConfigError
+
+
 type envelope_name = string
 
 type envelope_dependency = {
@@ -13,6 +17,10 @@ type envelope_spec = {
 }
 
 type t = {
-  envelopes           : envelope_spec list;
-  direct_dependencies : envelope_dependency list;
+  envelopes             : envelope_spec list;
+  explicit_dependencies : envelope_dependency list;
 }
+
+
+let write (_abspath_deps_config : abs_path) (_deps_config : t) : (unit, config_error) result =
+  failwith "TODO: DepsConfig.write"
diff --git a/bin-saphe/lockConfig.ml b/bin-saphe/lockConfig.ml
index ab6157df1..1ccd3988b 100644
--- a/bin-saphe/lockConfig.ml
+++ b/bin-saphe/lockConfig.ml
@@ -19,6 +19,7 @@ type lock_dependency = {
   used_as            : string;
 }
 
+(* TODO: make `locked_package` keep registry, package name, and version *)
 type locked_package = {
   lock_name         : lock_name;
   lock_contents     : lock_contents;
diff --git a/bin-saphe/main.ml b/bin-saphe/main.ml
index e1ec2b5e2..7d569a29d 100644
--- a/bin-saphe/main.ml
+++ b/bin-saphe/main.ml
@@ -735,13 +735,35 @@ type build_input =
     }
 
 
-let make_deps_config (_lock_config : LockConfig.t) : DepsConfig.t =
+let make_envelope_dependency (lock_dep : LockConfig.lock_dependency) : DepsConfig.envelope_dependency =
   DepsConfig.{
-    envelopes = failwith "TODO: DepsConfig";
-    direct_dependencies = [];
+    dependency_name    = lock_dep.depended_lock_name;
+    dependency_used_as = lock_dep.used_as;
   }
 
 
+let make_envelope_spec (locked_package : LockConfig.locked_package) : DepsConfig.envelope_spec =
+  let envelope_dependencies =
+    locked_package.lock_dependencies |> List.map make_envelope_dependency
+  in
+  DepsConfig.{
+    envelope_name = locked_package.lock_name;
+    envelope_path = failwith "TODO: make_envelope_spec, envelope_path";
+    envelope_dependencies;
+  }
+
+
+let make_deps_config (lock_config : LockConfig.t) : DepsConfig.t =
+  let envelopes =
+    lock_config.LockConfig.locked_packages |> List.map make_envelope_spec
+  in
+  let explicit_dependencies =
+    lock_config.LockConfig.explicit_dependencies
+      |> List.map make_envelope_dependency
+  in
+  DepsConfig.{ envelopes; explicit_dependencies }
+
+
 let build
     ~(fpath_in : string)
     ~(fpath_out_opt : string option)
@@ -813,22 +835,27 @@ let build
     | PackageBuildInput{
         root     = _absdir_package;
         lock     = abspath_lock_config;
-        deps     = _abspath_deps_config;
+        deps     = abspath_deps_config;
         envelope = _abspath_envelope_config;
         options  = _build_option;
       } ->
         let* lock_config = LockConfig.load abspath_lock_config in
-        let _deps_config = make_deps_config lock_config in
+        let deps_config = make_deps_config lock_config in
+
+        let* () = DepsConfig.write abspath_deps_config deps_config in
         failwith "TODO: PackageBuildInput"
 
     | DocumentBuildInput{
         lock    = abspath_lock_config;
-        deps    = _abspath_deps_config;
+        deps    = abspath_deps_config;
         out     = _abspath_out;
         dump    = _abspath_dump;
         options = _build_option;
       } ->
-        let* _lock_config = LockConfig.load abspath_lock_config in
+        let* lock_config = LockConfig.load abspath_lock_config in
+        let deps_config = make_deps_config lock_config in
+
+        let* () = DepsConfig.write abspath_deps_config deps_config in
         failwith "TODO: DocumentBuildInput"
   in
   match res with