@@ -322,6 +322,14 @@ func setProviderDefaults() {
 		viper.SetDefault("agents.title.model", models.AzureGPT41Mini)
 		return
 	}
+
+	// Google Cloud VertexAI configuration
+	if hasVertexAICredentials() {
+		viper.SetDefault("agents.coder.model", models.VertexAIGemini25)
+		viper.SetDefault("agents.task.model", models.VertexAIGemini25Flash)
+		viper.SetDefault("agents.title.model", models.VertexAIGemini25Flash)
+		return
+	}
 }
 
 // hasAWSCredentials checks if AWS credentials are available in the environment.
@@ -350,6 +358,19 @@ func hasAWSCredentials() bool {
 	return false
 }
 
+// hasVertexAICredentials checks if VertexAI credentials are available in the environment.
+func hasVertexAICredentials() bool {
+	// Check for explicit VertexAI parameters
+	if os.Getenv("VERTEXAI_PROJECT") != "" || os.Getenv("VERTEXAI_LOCATION") != "" {
+		return true
+	}
+	// Check for Google Cloud project and location
+	if os.Getenv("GOOGLE_CLOUD_PROJECT") != "" && (os.Getenv("GOOGLE_CLOUD_REGION") != "" && os.Getenv("GOOGLE_CLOUD_LOCATION") != "") {
+		return true
+	}
+	return false
+}
+
 // readConfig handles the result of reading a configuration file.
 func readConfig(err error) error {
 	if err == nil {