diff --git a/apps/api/pyproject.toml b/apps/api/pyproject.toml
index 3ef7755db..955feb071 100644
--- a/apps/api/pyproject.toml
+++ b/apps/api/pyproject.toml
@@ -37,6 +37,8 @@ dependencies = [
     # 請參閱 apps/api/Dockerfile Phase 6.4i 註解
     # Phase 9: Agent Teams - Claude Agent SDK
     "claude-agent-sdk>=0.1.50",
+    # Sprint 5.1 2026-04-08 Claude Sonnet 4.6: Service Registry YAML 讀取
+    "pyyaml>=6.0.0",
 ]
 
 # [tool.uv.sources]
diff --git a/packages/shared-types/schemas/api-types.json b/packages/shared-types/schemas/api-types.json
index c5436fa34..034157e47 100644
--- a/packages/shared-types/schemas/api-types.json
+++ b/packages/shared-types/schemas/api-types.json
@@ -1931,6 +1931,26 @@
           "description": "人工補充說明",
           "title": "Notes"
         },
+        "requires_approval_level": {
+          "default": "auto",
+          "description": "auto=直接執行, standard=1票, critical=2票MultiSig（由 Service Registry 決定）",
+          "title": "Requires Approval Level",
+          "type": "string"
+        },
+        "stateful_targets": {
+          "description": "此 Playbook 操作的 Stateful 服務清單，對應 service-registry.yaml",
+          "items": {
+            "type": "string"
+          },
+          "title": "Stateful Targets",
+          "type": "array"
+        },
+        "requires_pre_backup": {
+          "default": false,
+          "description": "執行前是否需要 Pre-flight 備份檢查",
+          "title": "Requires Pre Backup",
+          "type": "boolean"
+        },
         "created_at": {
           "format": "date-time",
           "title": "Created At",
diff --git a/packages/shared-types/src/api-types.ts b/packages/shared-types/src/api-types.ts
index cea269ef5..5c8150d9d 100644
--- a/packages/shared-types/src/api-types.ts
+++ b/packages/shared-types/src/api-types.ts
@@ -648,6 +648,18 @@ export type Tags = string[];
  * 人工補充說明
  */
 export type Notes = string | null;
+/**
+ * auto=直接執行, standard=1票, critical=2票MultiSig（由 Service Registry 決定）
+ */
+export type RequiresApprovalLevel = string;
+/**
+ * 此 Playbook 操作的 Stateful 服務清單，對應 service-registry.yaml
+ */
+export type StatefulTargets = string[];
+/**
+ * 執行前是否需要 Pre-flight 備份檢查
+ */
+export type RequiresPreBackup = boolean;
 export type CreatedAt6 = string;
 export type UpdatedAt3 = string;
 export type SuccessRate = number;
@@ -1349,6 +1361,9 @@ export interface Playbook {
   approved_at?: ApprovedAt;
   tags?: Tags;
   notes?: Notes;
+  requires_approval_level?: RequiresApprovalLevel;
+  stateful_targets?: StatefulTargets;
+  requires_pre_backup?: RequiresPreBackup;
   created_at?: CreatedAt6;
   updated_at?: UpdatedAt3;
   [k: string]: unknown;