diff --git a/pkg/gateway/server.go b/pkg/gateway/server.go
index b0ab41d5..3c96344e 100644
--- a/pkg/gateway/server.go
+++ b/pkg/gateway/server.go
@@ -1444,6 +1444,21 @@ func (s *Server) DiscoverCodeUnits(ctx context.Context, req *gatewayv1.DiscoverC
 
 // ─── Build / Lint / Test ─────────────────────────────────────
 
+// composeStatusOutput surfaces a typed runtime status message alongside raw
+// agent output. Agents that already fold the actionable message into raw output
+// (as Generic does) would otherwise show it twice, so the message is only
+// prepended when the raw output does not already carry it.
+func composeStatusOutput(message, output string) string {
+	message = strings.TrimSpace(message)
+	if message == "" || strings.Contains(output, message) {
+		return output
+	}
+	if output == "" {
+		return message
+	}
+	return message + "\n" + output
+}
+
 func (s *Server) Build(ctx context.Context, _ *gatewayv1.BuildRequest) (*gatewayv1.BuildResponse, error) {
 	service, err := s.executionServiceBehavior()
 	if err != nil {
@@ -1456,7 +1471,7 @@ func (s *Server) Build(ctx context.Context, _ *gatewayv1.BuildRequest) (*gateway
 	success := resp.Status != nil && resp.Status.State == runtimev0.BuildStatus_SUCCESS
 	output := resp.Output
 	if !success && resp.Status != nil {
-		output = resp.Status.Message + "\n" + output
+		output = composeStatusOutput(resp.Status.Message, output)
 	}
 	var buildErrors []*gatewayv1.BuildError
 	if !success {
@@ -1477,7 +1492,7 @@ func (s *Server) Lint(ctx context.Context, _ *gatewayv1.LintRequest) (*gatewayv1
 	success := resp.Status != nil && resp.Status.State == runtimev0.LintStatus_SUCCESS
 	output := resp.Output
 	if !success && resp.Status != nil {
-		output = resp.Status.Message + "\n" + output
+		output = composeStatusOutput(resp.Status.Message, output)
 	}
 	var lintErrors []*gatewayv1.BuildError
 	if !success {
diff --git a/pkg/gateway/server_test.go b/pkg/gateway/server_test.go
index addd9158..0b150d23 100644
--- a/pkg/gateway/server_test.go
+++ b/pkg/gateway/server_test.go
@@ -56,7 +56,9 @@ type mockCodeClient struct {
 }
 
 type mockRuntimeClient struct {
-	testFn func(ctx context.Context, in *runtimev0.TestRequest, opts ...grpc.CallOption) (*runtimev0.TestResponse, error)
+	testFn  func(ctx context.Context, in *runtimev0.TestRequest, opts ...grpc.CallOption) (*runtimev0.TestResponse, error)
+	buildFn func(ctx context.Context, in *runtimev0.BuildRequest, opts ...grpc.CallOption) (*runtimev0.BuildResponse, error)
+	lintFn  func(ctx context.Context, in *runtimev0.LintRequest, opts ...grpc.CallOption) (*runtimev0.LintResponse, error)
 }
 
 type mockServiceExecution struct {
@@ -172,8 +174,11 @@ func (m *mockRuntimeClient) Stop(context.Context, *runtimev0.StopRequest, ...grp
 func (m *mockRuntimeClient) Destroy(context.Context, *runtimev0.DestroyRequest, ...grpc.CallOption) (*runtimev0.DestroyResponse, error) {
 	return nil, fmt.Errorf("not exercised in mock")
 }
-func (m *mockRuntimeClient) Build(context.Context, *runtimev0.BuildRequest, ...grpc.CallOption) (*runtimev0.BuildResponse, error) {
-	return nil, fmt.Errorf("not exercised in mock")
+func (m *mockRuntimeClient) Build(ctx context.Context, in *runtimev0.BuildRequest, opts ...grpc.CallOption) (*runtimev0.BuildResponse, error) {
+	if m.buildFn == nil {
+		return nil, fmt.Errorf("Build not configured")
+	}
+	return m.buildFn(ctx, in, opts...)
 }
 func (m *mockRuntimeClient) Test(ctx context.Context, in *runtimev0.TestRequest, opts ...grpc.CallOption) (*runtimev0.TestResponse, error) {
 	if m.testFn == nil {
@@ -181,8 +186,11 @@ func (m *mockRuntimeClient) Test(ctx context.Context, in *runtimev0.TestRequest,
 	}
 	return m.testFn(ctx, in, opts...)
 }
-func (m *mockRuntimeClient) Lint(context.Context, *runtimev0.LintRequest, ...grpc.CallOption) (*runtimev0.LintResponse, error) {
-	return nil, fmt.Errorf("not exercised in mock")
+func (m *mockRuntimeClient) Lint(ctx context.Context, in *runtimev0.LintRequest, opts ...grpc.CallOption) (*runtimev0.LintResponse, error) {
+	if m.lintFn == nil {
+		return nil, fmt.Errorf("Lint not configured")
+	}
+	return m.lintFn(ctx, in, opts...)
 }
 func (m *mockRuntimeClient) Information(context.Context, *runtimev0.InformationRequest, ...grpc.CallOption) (*runtimev0.InformationResponse, error) {
 	return nil, fmt.Errorf("not exercised in mock")
@@ -601,6 +609,74 @@ func TestTestPreservesStructuredRuntimeFields(t *testing.T) {
 	}
 }
 
+func TestBuildDoesNotDuplicateStatusMessageInOutput(t *testing.T) {
+	const msg = "build not available: generic agent has no language knowledge"
+	rt := &mockRuntimeClient{
+		buildFn: func(_ context.Context, _ *runtimev0.BuildRequest, _ ...grpc.CallOption) (*runtimev0.BuildResponse, error) {
+			return &runtimev0.BuildResponse{
+				Output: msg,
+				Status: &runtimev0.BuildStatus{State: runtimev0.BuildStatus_ERROR, Message: msg},
+			}, nil
+		},
+	}
+	s := newTestServerWithRuntime(rt)
+
+	resp, err := s.Build(context.Background(), &gatewayv1.BuildRequest{})
+	if err != nil {
+		t.Fatalf("Build: %v", err)
+	}
+	if resp.Success {
+		t.Fatal("Success = true, want false")
+	}
+	if resp.Output != msg {
+		t.Fatalf("Output = %q, want the message surfaced once", resp.Output)
+	}
+}
+
+func TestBuildPrependsDistinctStatusMessage(t *testing.T) {
+	rt := &mockRuntimeClient{
+		buildFn: func(_ context.Context, _ *runtimev0.BuildRequest, _ ...grpc.CallOption) (*runtimev0.BuildResponse, error) {
+			return &runtimev0.BuildResponse{
+				Output: "compiler: undefined symbol",
+				Status: &runtimev0.BuildStatus{State: runtimev0.BuildStatus_ERROR, Message: "build failed"},
+			}, nil
+		},
+	}
+	s := newTestServerWithRuntime(rt)
+
+	resp, err := s.Build(context.Background(), &gatewayv1.BuildRequest{})
+	if err != nil {
+		t.Fatalf("Build: %v", err)
+	}
+	if resp.Output != "build failed\ncompiler: undefined symbol" {
+		t.Fatalf("Output = %q, want status context preserved ahead of native output", resp.Output)
+	}
+}
+
+func TestLintDoesNotDuplicateStatusMessageInOutput(t *testing.T) {
+	const msg = "lint not available: generic agent has no language knowledge"
+	rt := &mockRuntimeClient{
+		lintFn: func(_ context.Context, _ *runtimev0.LintRequest, _ ...grpc.CallOption) (*runtimev0.LintResponse, error) {
+			return &runtimev0.LintResponse{
+				Output: msg,
+				Status: &runtimev0.LintStatus{State: runtimev0.LintStatus_ERROR, Message: msg},
+			}, nil
+		},
+	}
+	s := newTestServerWithRuntime(rt)
+
+	resp, err := s.Lint(context.Background(), &gatewayv1.LintRequest{})
+	if err != nil {
+		t.Fatalf("Lint: %v", err)
+	}
+	if resp.Success {
+		t.Fatal("Success = true, want false")
+	}
+	if resp.Output != msg {
+		t.Fatalf("Output = %q, want the message surfaced once", resp.Output)
+	}
+}
+
 func TestFix(t *testing.T) {
 	mock := &mockCodeClient{
 		fixFn: func(_ context.Context, in *codev0.FixRequest, _ ...grpc.CallOption) (*codev0.FixResponse, error) {