diff --git a/pkg/parser/schemas/main_workflow_schema.json b/pkg/parser/schemas/main_workflow_schema.json
index b347303a7e..359f5df38c 100644
--- a/pkg/parser/schemas/main_workflow_schema.json
+++ b/pkg/parser/schemas/main_workflow_schema.json
@@ -6787,8 +6787,8 @@
       "oneOf": [
         {
           "type": "string",
-          "enum": ["claude", "codex", "copilot"],
-          "description": "Simple engine name: 'claude' (default, Claude Code), 'copilot' (GitHub Copilot CLI), or 'codex' (OpenAI Codex CLI)"
+          "enum": ["claude", "codex", "copilot", "custom"],
+          "description": "Simple engine name: 'claude' (default, Claude Code), 'copilot' (GitHub Copilot CLI), 'codex' (OpenAI Codex CLI), or 'custom' (bring your own AI provider)"
         },
         {
           "type": "object",
@@ -6796,8 +6796,8 @@
           "properties": {
             "id": {
               "type": "string",
-              "enum": ["claude", "codex", "copilot"],
-              "description": "AI engine identifier: 'claude' (Claude Code), 'codex' (OpenAI Codex CLI), or 'copilot' (GitHub Copilot CLI)"
+              "enum": ["claude", "codex", "copilot", "custom"],
+              "description": "AI engine identifier: 'claude' (Claude Code), 'codex' (OpenAI Codex CLI), 'copilot' (GitHub Copilot CLI), or 'custom' (bring your own AI provider)"
             },
             "version": {
               "type": ["string", "number"],
diff --git a/pkg/workflow/agentic_engine_test.go b/pkg/workflow/agentic_engine_test.go
index 46f80b3252..225a900801 100644
--- a/pkg/workflow/agentic_engine_test.go
+++ b/pkg/workflow/agentic_engine_test.go
@@ -11,8 +11,8 @@ func TestEngineRegistry(t *testing.T) {
 
 	// Test that built-in engines are registered
 	supportedEngines := registry.GetSupportedEngines()
-	if len(supportedEngines) != 3 {
-		t.Errorf("Expected 3 supported engines, got %d", len(supportedEngines))
+	if len(supportedEngines) != 4 {
+		t.Errorf("Expected 4 supported engines, got %d", len(supportedEngines))
 	}
 
 	// Test getting engines by ID
@@ -104,9 +104,9 @@ func TestEngineRegistryCustomEngine(t *testing.T) {
 		t.Error("Expected test-custom engine to be experimental")
 	}
 
-	// Test that supported engines list is updated (3 built-in + 1 custom = 4)
+	// Test that supported engines list is updated (4 built-in + 1 custom = 5)
 	supportedEngines := registry.GetSupportedEngines()
-	if len(supportedEngines) != 4 {
-		t.Errorf("Expected 4 supported engines after adding test-custom, got %d", len(supportedEngines))
+	if len(supportedEngines) != 5 {
+		t.Errorf("Expected 5 supported engines after adding test-custom, got %d", len(supportedEngines))
 	}
 }
diff --git a/pkg/workflow/engine_helpers.go b/pkg/workflow/engine_helpers.go
index 4e9e38438e..1f216d528d 100644
--- a/pkg/workflow/engine_helpers.go
+++ b/pkg/workflow/engine_helpers.go
@@ -214,7 +214,7 @@ func InjectCustomEngineSteps(
 	workflowData *WorkflowData,
 	convertStepFunc func(map[string]any) (string, error),
 ) []GitHubActionStep {
-	var steps []GitHubActionStep
+	steps := []GitHubActionStep{}
 
 	// Handle custom steps if they exist in engine config
 	if workflowData.EngineConfig != nil && len(workflowData.EngineConfig.Steps) > 0 {
diff --git a/pkg/workflow/max_turns_test.go b/pkg/workflow/max_turns_test.go
index 4b313ab6d9..82012bc3fe 100644
--- a/pkg/workflow/max_turns_test.go
+++ b/pkg/workflow/max_turns_test.go
@@ -273,7 +273,7 @@ engine:
 
 # Custom Engine with Max Turns
 
-This tests max-turns feature with custom engine.`
+This tests that max-turns is rejected with custom engine.`
 
 	// Create a temporary directory for the test
 	tmpDir := testutil.TempDir(t, "custom-max-turns-test")
@@ -284,34 +284,22 @@ This tests max-turns feature with custom engine.`
 		t.Fatal(err)
 	}
 
-	// Compile the workflow
+	// Compile the workflow - should fail because custom engine doesn't support max-turns
 	compiler := NewCompiler()
-	if err := compiler.CompileWorkflow(testFile); err != nil {
-		t.Fatalf("Failed to compile workflow with custom engine and max-turns: %v", err)
+	err := compiler.CompileWorkflow(testFile)
+	
+	// Expect an error about max-turns not being supported
+	if err == nil {
+		t.Fatal("Expected compilation to fail with max-turns error, but it succeeded")
 	}
-
-	// Read the generated lock file
-	lockFile := stringutil.MarkdownToLockFile(testFile)
-	lockContent, err := os.ReadFile(lockFile)
-	if err != nil {
-		t.Fatalf("Failed to read lock file: %v", err)
-	}
-
-	lockContentStr := string(lockContent)
-
-	// Verify GH_AW_MAX_TURNS environment variable is set
-	expectedEnvVar := "GH_AW_MAX_TURNS: \"5\""
-	if !strings.Contains(lockContentStr, expectedEnvVar) {
-		t.Errorf("Expected GH_AW_MAX_TURNS environment variable to be set. Expected: %s\nActual content:\n%s", expectedEnvVar, lockContentStr)
+	
+	// Verify the error message mentions max-turns not being supported
+	if !strings.Contains(err.Error(), "max-turns not supported") {
+		t.Errorf("Expected error about max-turns not supported, got: %v", err)
 	}
-
-	// Verify MCP config is generated for custom engine
-	if !strings.Contains(lockContentStr, "/tmp/gh-aw/mcp-config/mcp-servers.json") {
-		t.Error("Expected custom engine to generate MCP configuration file")
-	}
-
-	// Verify custom steps are included
-	if !strings.Contains(lockContentStr, "echo \"Testing max-turns with custom engine\"") {
-		t.Error("Expected custom steps to be included in generated workflow")
+	
+	// Verify the error message mentions the custom engine
+	if !strings.Contains(err.Error(), "custom") {
+		t.Errorf("Expected error to mention 'custom' engine, got: %v", err)
 	}
 }