diff --git a/pipeline_service/agent_loop.py b/pipeline_service/agent_loop.py
index 69cc10e..fd8bc37 100644
--- a/pipeline_service/agent_loop.py
+++ b/pipeline_service/agent_loop.py
@@ -2032,6 +2032,28 @@ def _parse_agent_action(raw):
         if isinstance(d, dict) and 'tool' in d:
             return {"action": "tool_call", "tool": d.get("tool", ""), "params": d.get("params") or {}}
 
+    # 裸 JSON 动作对象扫描（2026-09-15 pbls M1a 实测）：LLM 连续输出多个无围栏的
+    # {"action":"tool_call",...} 对象（一行一个）——整体 json.loads 失败（多对象拼接）、
+    # 围栏扫描无命中 → 兜底把 tool_call 文本当交付件正文 deliver → 交付件 content
+    # 就是 JSON 文本、files_json 只有快照文件，QC 必退且退回理由失真。
+    # raw_decode 逐个扫描，取第一个可解析的动作对象。
+    _dec = json.JSONDecoder()
+    _idx = 0
+    while True:
+        _b = raw.find('{', _idx)
+        if _b < 0:
+            break
+        try:
+            _d, _end = _dec.raw_decode(raw[_b:])
+        except (json.JSONDecodeError, ValueError):
+            _idx = _b + 1
+            continue
+        if isinstance(_d, dict) and 'action' in _d:
+            return _d
+        if isinstance(_d, dict) and 'tool' in _d:
+            return {"action": "tool_call", "tool": _d.get("tool", ""), "params": _d.get("params") or {}}
+        _idx = _b + max(_end, 1)
+
     return {"action": "deliver", "result": raw}