diff --git a/conformance_test.go b/conformance_test.go
index 988a256..4fbebf9 100644
--- a/conformance_test.go
+++ b/conformance_test.go
@@ -47,6 +47,7 @@ func sampleMessage() Message {
 			{Type: PartToolResult, Process: true, ToolResult: &ToolResultPart{CallID: "call_1", Status: "ok", Summary: "3 条命中"}},
 			{Type: PartText, Text: "根据历史记录……"},
 			{Type: PartArtifactRef, Artifact: &ArtifactRef{ArtifactID: "art_abc123def456", Name: "报告.md", Kind: "document"}},
+			{Type: PartCard, Card: &CardPart{Kind: "result", Data: []UINode{{Type: "markdown", Markdown: "全文见卡片"}}, CardID: "card_abc123def456"}},
 		},
 	}
 }
@@ -176,7 +177,7 @@ func TestGoldenProfileAndTools(t *testing.T) {
 	golden(t, "tool_http", ToolDesc{
 		Name: "http_translate", Description: "调用翻译 API", Source: SourceUser,
 		Parameters: json.RawMessage(`{"type":"object","properties":{"text":{"type":"string"}},"required":["text"]}`),
-		HTTP: &HTTPToolSpec{Method: "POST", URL: "https://api.example.com/translate", BodyTemplate: `{"q":"{{param.text}}"}`, TimeoutMs: 10000, ResultPath: "data.0"},
+		HTTP:       &HTTPToolSpec{Method: "POST", URL: "https://api.example.com/translate", BodyTemplate: `{"q":"{{param.text}}"}`, TimeoutMs: 10000, ResultPath: "data.0"},
 	})
 }
 
diff --git a/model.go b/model.go
index 08f028e..ddb4128 100644
--- a/model.go
+++ b/model.go
@@ -124,9 +124,12 @@ type ErrorPart struct {
 }
 
 // CardPart.Data 是 UI schema 节点（4.6 有限词汇）。
+// CardID 非空 = 收件箱 ActivityCard 的引用部件（如 submit_card 产卡：卡片为产物
+// 权威载体，消息只存引用+锚点渲染）；空 = 插件内嵌卡片部件（自包含 Data）。
 type CardPart struct {
-	Kind string  `json:"kind"`
-	Data []UINode `json:"data"`
+	Kind   string   `json:"kind"`
+	Data   []UINode `json:"data"`
+	CardID ID       `json:"cardId,omitempty"`
 }
 
 // ---- Run（一切运行皆 Run）----
diff --git a/testdata/golden/message.json b/testdata/golden/message.json
index 13b9708..a774ab6 100644
--- a/testdata/golden/message.json
+++ b/testdata/golden/message.json
@@ -39,6 +39,19 @@
         "name": "报告.md",
         "kind": "document"
       }
+    },
+    {
+      "type": "card",
+      "card": {
+        "kind": "result",
+        "data": [
+          {
+            "type": "markdown",
+            "markdown": "全文见卡片"
+          }
+        ],
+        "cardId": "card_abc123def456"
+      }
     }
   ],
   "createdAt": "0001-01-01T00:00:00Z"
diff --git a/ts/types.ts b/ts/types.ts
index ef4927b..bd6b748 100644
--- a/ts/types.ts
+++ b/ts/types.ts
@@ -32,7 +32,7 @@ export interface Part {
   artifact?: { artifactId: ID; name: string; kind?: string };
   hitl?: { cardId: ID; question: string; resolved: boolean; answer?: string };
   plan?: PlanSnapshot;
-  card?: { kind: string; data: UINode[] };
+  card?: { kind: string; data: UINode[]; cardId?: ID }; // cardId 非空 = 收件箱卡片引用部件（submit_card）
   error?: { code: string; message: string };
   process?: boolean; // run 终态后折叠为摘要行
 }