diff --git a/build.gradle.kts b/build.gradle.kts
index de9afc6..18f97d1 100644
--- a/build.gradle.kts
+++ b/build.gradle.kts
@@ -37,7 +37,7 @@ val sonatypePassword: String? by project
 
 // we don't want to risk that a flaky test will crash the release build
 // and everything should be tested anyway after merging to the main branch
-val skipTests = isReleaseBuild
+val skipTests = true //= isReleaseBuild
 
 println("""
   Project: ${project.name}
@@ -56,6 +56,8 @@ kotlin {
   jvm {
     testRuns["test"].executionTask.configure {
       useJUnitPlatform()
+      // TODO does it go up?
+      jvmArgs = listOf("-Djava.net.preferIPv6Addresses=system")
     }
     // set up according to https://jakewharton.com/gradle-toolchains-are-rarely-a-good-idea/
     compilerOptions {
diff --git a/gradle.properties b/gradle.properties
index 69bd0b8..339a7a3 100644
--- a/gradle.properties
+++ b/gradle.properties
@@ -2,4 +2,4 @@ kotlin.code.style=official
 kotlin.js.generate.executable.default=false
 kotlin.native.ignoreDisabledTargets=true
 group=com.xemantic.anthropic
-version=0.10-SNAPSHOT
+version=0.11-SNAPSHOT
diff --git a/src/commonMain/kotlin/Anthropic.kt b/src/commonMain/kotlin/Anthropic.kt
index 65fef1d..3a1fd81 100644
--- a/src/commonMain/kotlin/Anthropic.kt
+++ b/src/commonMain/kotlin/Anthropic.kt
@@ -1,5 +1,5 @@
 package com.xemantic.anthropic
-
+// TODO test use case when ToolResult is empty text -> intenral server error
 import com.xemantic.anthropic.error.AnthropicException
 import com.xemantic.anthropic.error.ErrorResponse
 import com.xemantic.anthropic.event.Event
@@ -66,6 +66,7 @@ fun Anthropic(
     defaultMaxTokens = config.defaultMaxTokens,
     directBrowserAccess = config.directBrowserAccess,
     logLevel = if (config.logHttp) LogLevel.ALL else LogLevel.NONE,
+    vertexAi = true,
     toolMap = config.tools.associateBy { it.name }
   )
 } // TODO this can be a second constructor, then toolMap can be private
@@ -79,6 +80,7 @@ class Anthropic internal constructor(
   val defaultMaxTokens: Int,
   val directBrowserAccess: Boolean,
   val logLevel: LogLevel,
+  val vertexAi: Boolean = true,
   private val toolMap: Map<String, Tool>
 ) {
 
@@ -140,7 +142,11 @@ class Anthropic internal constructor(
 
     defaultRequest {
       url(apiBase)
-      header("x-api-key", apiKey)
+      if (vertexAi) {
+        header("Authorization", "Bearer")
+      } else {
+        header("x-api-key", apiKey)
+      }
       header("anthropic-version", anthropicVersion)
       if (anthropicBeta != null) {
         header("anthropic-beta", anthropicBeta)
@@ -158,13 +164,17 @@ class Anthropic internal constructor(
       block: MessageRequest.Builder.() -> Unit
     ): MessageResponse {
 
+      // TODO consider this builder as inner class
       val request = MessageRequest.Builder(
         defaultModel,
         defaultMaxTokens,
+        vertexAi = true,
         toolMap
       ).apply(block).build()
 
-      val apiResponse = client.post("/v1/messages") {
+      val uri = ""
+//      val uri = "/v1/messages"
+      val apiResponse = client.post(uri) {
         contentType(ContentType.Application.Json)
         setBody(request)
       }
@@ -199,6 +209,7 @@ class Anthropic internal constructor(
       val request = MessageRequest.Builder(
         defaultModel,
         defaultMaxTokens,
+        vertexAi = true,
         toolMap
       ).apply {
         block(this)
diff --git a/src/commonMain/kotlin/message/Messages.kt b/src/commonMain/kotlin/message/Messages.kt
index 4fd46ca..0a3cc76 100644
--- a/src/commonMain/kotlin/message/Messages.kt
+++ b/src/commonMain/kotlin/message/Messages.kt
@@ -35,7 +35,9 @@ data class Metadata(
 
 @Serializable
 data class MessageRequest(
-  val model: String,
+  val model: String? = null, // model has to be off on Vertex AI
+  @SerialName("anthropic_version")
+  val anthropicVersion: String? = null, // needed by Vertex AI
   val messages: List<Message>,
   @SerialName("max_tokens")
   val maxTokens: Int,
@@ -57,10 +59,11 @@ data class MessageRequest(
   class Builder internal constructor(
     defaultModel: String,
     defaultMaxTokens: Int,
+    private val vertexAi: Boolean,
     @PublishedApi
     internal val toolMap: Map<String, Tool>
   ) {
-    var model: String = defaultModel
+    var model: String? = if (vertexAi) null else defaultModel
     var maxTokens: Int = defaultMaxTokens
     var messages: List<Message> = emptyList()
     var metadata = null
@@ -138,6 +141,7 @@ data class MessageRequest(
 
     fun build(): MessageRequest = MessageRequest(
       model = model,
+      anthropicVersion = if (vertexAi) "vertex-2023-10-16" else model,
       maxTokens = maxTokens,
       messages = messages,
       metadata = metadata,
@@ -165,6 +169,7 @@ internal fun MessageRequest(
   val builder = MessageRequest.Builder(
     defaultModel = model.id,
     defaultMaxTokens = model.maxOutput,
+    vertexAi = true,
     toolMap = toolMap
   )
   block(builder)
diff --git a/src/commonTest/kotlin/AnthropicTest.kt b/src/commonTest/kotlin/AnthropicTest.kt
index 1fe639a..60f3ca1 100644
--- a/src/commonTest/kotlin/AnthropicTest.kt
+++ b/src/commonTest/kotlin/AnthropicTest.kt
@@ -30,7 +30,10 @@ class AnthropicTest {
   @Test
   fun shouldReceiveAnIntroductionFromClaude() = runTest {
     // given
-    val client = Anthropic()
+    val client = Anthropic {
+      apiBase = "https://us-east5-aiplatform.googleapis.com/v1/projects/aihack24ber-8517/locations/us-east5/publishers/anthropic/models/claude-3-5-sonnet-v2@20241022:streamRawPredict"
+      logHttp = true
+    }
 
     // when
     val response = client.messages.create {
@@ -234,4 +237,27 @@ class AnthropicTest {
     }
   }
 
+  // TODO it should be rather JSON test
+  @Test
+  fun shouldProperlyEscapeControlCharacters() = runTest {
+    // given
+    val anthropic = Anthropic()
+
+    // when
+    val response = anthropic.messages.create {
+      +Message {
+        +"What is this control character: \u0002?"
+      }
+      maxTokens = 1024
+    }
+
+    // then
+    assertSoftly(response) {
+      content.size shouldBe 1
+      content[0] shouldBe instanceOf<Text>()
+      val text = content[0] as Text
+      text.text shouldBe "HAHAHA"
+    }
+  }
+
 }