diff --git a/apps/api/src/services/telegram_gateway.py b/apps/api/src/services/telegram_gateway.py
index fee11225..26222de2 100644
--- a/apps/api/src/services/telegram_gateway.py
+++ b/apps/api/src/services/telegram_gateway.py
@@ -2598,7 +2598,14 @@ class TelegramGateway:
                     await self._answer_callback(callback_query_id, action, text="🔄 重診排程中...")
                     await self._send_reanalyze_result(incident_id)
                 else:
-                    await self._answer_callback(callback_query_id, action, text="⚠️ 未知操作")
+                    # 2026-04-14 Claude Sonnet 4.6 (Phase 5 Sprint 5.1):
+                    # 未知 action → fallback dispatcher (查看 callback_action_spec.yaml 是否有註冊)
+                    await self._dispatch_category_action(
+                        callback_query_id=callback_query_id,
+                        action=action,
+                        incident_id=incident_id,
+                        user_id=user_id,
+                    )
 
                 return {
                     "action": action,
@@ -2608,7 +2615,11 @@ class TelegramGateway:
                     "info_action": True,
                 }
 
-            nonce = parsed["nonce"]
+            nonce = parsed["nonce"]  # 4-part nonce action
+
+            # 2026-04-14 Claude Sonnet 4.6 (Phase 5 Sprint 5.1):
+            # 寫類 nonce action 先驗 nonce 再 fallback dispatcher（若 action 在 registry）
+            # 這段邏輯在 Step 2 之後再處理，這裡只是佔位註解
 
             # 驗證使用者 + Nonce
             user = await self._security.verify_callback(
@@ -3445,6 +3456,86 @@ class TelegramGateway:
         )
         return True
 
+    async def _dispatch_category_action(
+        self,
+        callback_query_id: str,
+        action: str,
+        incident_id: str,
+        user_id: int,
+    ) -> None:
+        """
+        Phase 5 Sprint 5.1 (2026-04-14 Claude Sonnet 4.6):
+        Fallback dispatcher — 未知 info action 查 callback_action_spec.yaml
+
+        流程:
+        1. 查 action registry
+        2. 若不存在 → 原「⚠️ 未知操作」回覆
+        3. 若存在 → 從 incident 取 labels → dispatch_action → reply_to 原卡片
+
+        注意: 此方法只處理 info action (查類)。nonce action (寫類) 走另一路徑。
+        """
+        from src.services.callback_dispatcher import dispatch_action, get_action_spec
+
+        spec = get_action_spec(action)
+        if not spec:
+            await self._answer_callback(callback_query_id, action, text="⚠️ 未知操作")
+            return
+
+        # Acknowledge callback immediately（避免 Telegram 端 timeout）
+        await self._answer_callback(
+            callback_query_id, action, text=f"{spec.emoji} 執行中..."
+        )
+
+        # 從 incident 取 labels (供模板替換)
+        labels: dict = {}
+        try:
+            from src.repositories.incident_repository import get_incident_repository
+            repo = get_incident_repository()
+            incident = await repo.get_by_id(incident_id)
+            if incident and incident.signals:
+                labels = incident.signals[0].labels or {}
+        except Exception as _e:
+            logger.debug("dispatch_labels_lookup_failed", incident_id=incident_id, error=str(_e))
+
+        # Dispatch
+        result = await dispatch_action(
+            action_name=action,
+            incident_id=incident_id,
+            user_id=user_id,
+            labels=labels,
+        )
+
+        # Reply to 原卡片 — 從 Redis tg_msg 查 message_id
+        try:
+            from src.core.redis_client import get_redis
+            redis = get_redis()
+            msg_id_raw = await redis.get(f"tg_msg:{incident_id}")
+            orig_msg_id = int(msg_id_raw) if msg_id_raw else None
+        except Exception:
+            orig_msg_id = None
+
+        try:
+            payload: dict = {
+                "chat_id": settings.OPENCLAW_TG_CHAT_ID,
+                "text": result.result_text,
+                "parse_mode": "HTML",
+            }
+            if orig_msg_id:
+                payload["reply_to_message_id"] = orig_msg_id
+            await self._http_client.post(
+                f"https://api.telegram.org/bot{settings.OPENCLAW_TG_BOT_TOKEN}/sendMessage",
+                json=payload,
+            )
+            logger.info(
+                "category_action_reply_sent",
+                action=action,
+                incident_id=incident_id,
+                success=result.success,
+                duration_ms=round(result.duration_ms, 1),
+            )
+        except Exception as _e:
+            logger.warning("category_action_reply_failed", action=action, error=str(_e))
+
     async def _send_incident_detail(self, incident_id: str) -> None:
         """
         ADR-050 P2: 傳送事件詳情訊息 (不修改原始簽核卡片)