diff --git a/pkg/memory/store.go b/pkg/memory/store.go
index 11526b27c..fe6e6a0ea 100644
--- a/pkg/memory/store.go
+++ b/pkg/memory/store.go
@@ -6,6 +6,14 @@ import (
 	"github.com/sipeed/picoclaw/pkg/providers"
 )
 
+// SessionMessage represents a message in a session with optional tags and metadata.
+type SessionMessage struct {
+	Role     string
+	Content  string
+	Tags     []string
+	Metadata map[string]interface{}
+}
+
 // Store defines an interface for persistent session storage.
 // Each method is an atomic operation — there is no separate Save() call.
 type Store interface {
diff --git a/pkg/memory/store_test.go b/pkg/memory/store_test.go
new file mode 100644
index 000000000..bfa756764
--- /dev/null
+++ b/pkg/memory/store_test.go
@@ -0,0 +1,23 @@
+package memory
+
+import (
+	"testing"
+)
+
+func TestSessionMessage_WithFrontmatter(t *testing.T) {
+	msg := SessionMessage{
+		Role:    "user",
+		Content: "test content",
+		Tags:    []string{"coding", "golang"},
+		Metadata: map[string]interface{}{
+			"session_id": "abc123",
+			"model":     "claude-sonnet-4",
+		},
+	}
+	if len(msg.Tags) != 2 {
+		t.Errorf("expected 2 tags, got %d", len(msg.Tags))
+	}
+	if msg.Metadata["session_id"] != "abc123" {
+		t.Errorf("expected session_id in metadata")
+	}
+}
\ No newline at end of file