diff --git a/backend/internal/trace/eino_test.go b/backend/internal/trace/eino_test.go
new file mode 100644
index 0000000..c42401c
--- /dev/null
+++ b/backend/internal/trace/eino_test.go
@@ -0,0 +1,42 @@
+package trace_test
+
+import (
+	"context"
+	"testing"
+
+	"github.com/cloudwego/eino/compose"
+	"github.com/hhs/camtalk/internal/trace"
+)
+
+func TestEinoContextPropagation(t *testing.T) {
+	ctx := context.Background()
+	testTraceID := "01J5TEST123456789"
+	ctx = trace.WithTraceID(ctx, testTraceID)
+
+	var capturedTraceID string
+
+	g := compose.NewGraph[string, string]()
+	g.AddLambdaNode("test_node", compose.InvokableLambda(
+		func(ctx context.Context, input string) (string, error) {
+			capturedTraceID = trace.GetTraceID(ctx)
+			return "ok", nil
+		},
+	))
+	g.AddEdge(compose.START, "test_node")
+	g.AddEdge("test_node", compose.END)
+
+	runnable, err := g.Compile(ctx)
+	if err != nil {
+		t.Fatalf("compile failed: %v", err)
+	}
+
+	_, err = runnable.Invoke(ctx, "test_input")
+	if err != nil {
+		t.Fatalf("invoke failed: %v", err)
+	}
+
+	if capturedTraceID != testTraceID {
+		t.Errorf("trace_id lost in Eino propagation: got %q, want %q",
+			capturedTraceID, testTraceID)
+	}
+}