diff --git a/packages/shared-types/schemas/api-types.json b/packages/shared-types/schemas/api-types.json
index 16737849..76001854 100644
--- a/packages/shared-types/schemas/api-types.json
+++ b/packages/shared-types/schemas/api-types.json
@@ -324,6 +324,19 @@
           "format": "date-time",
           "title": "Last Seen At",
           "type": "string"
+        },
+        "incident_id": {
+          "anyOf": [
+            {
+              "type": "string"
+            },
+            {
+              "type": "null"
+            }
+          ],
+          "default": null,
+          "description": "關聯的 Incident ID",
+          "title": "Incident Id"
         }
       },
       "required": [
diff --git a/packages/shared-types/src/api-types.ts b/packages/shared-types/src/api-types.ts
index f9b3cc51..3a8f4506 100644
--- a/packages/shared-types/src/api-types.ts
+++ b/packages/shared-types/src/api-types.ts
@@ -143,6 +143,10 @@ export type HitCount = number;
  * 最後觸發時間
  */
 export type LastSeenAt = string;
+/**
+ * 關聯的 Incident ID
+ */
+export type IncidentId = string | null;
 /**
  * 執行動作描述
  */
@@ -384,7 +388,7 @@ export type Fingerprint2 = string | null;
 /**
  * 事件唯一識別碼 (如 INC-20260322-A1B2C3)
  */
-export type IncidentId = string;
+export type IncidentId1 = string;
 /**
  * 事件狀態
  */
@@ -435,7 +439,7 @@ export type PersistedToPg = boolean;
 export type Vectorized = boolean;
 export type Signals1 = Signal[];
 export type AffectedServices1 = string[];
-export type IncidentId1 = string;
+export type IncidentId2 = string;
 export type Signals2 = Signal[];
 export type AffectedServices2 = string[];
 export type ProposalIds1 = string[];
@@ -827,6 +831,7 @@ export interface ApprovalRequest {
   fingerprint?: Fingerprint;
   hit_count?: HitCount;
   last_seen_at?: LastSeenAt;
+  incident_id?: IncidentId;
   [k: string]: unknown;
 }
 /**
@@ -1074,7 +1079,7 @@ export interface Annotations {
  * via the `definition` "Incident".
  */
 export interface Incident {
-  incident_id?: IncidentId;
+  incident_id?: IncidentId1;
   status?: IncidentStatus1;
   severity: Severity2;
   signals?: Signals;
@@ -1120,7 +1125,7 @@ export interface IncidentCreate {
  * via the `definition` "IncidentResponse".
  */
 export interface IncidentResponse {
-  incident_id: IncidentId1;
+  incident_id: IncidentId2;
   status: IncidentStatus;
   severity: Severity;
   signals: Signals2;