feat: 命令台子代理链路（主任务/模型子代理/委派子任务 + 过程调用实时同步）

host：链路条目带 thread 归属；delegate 向父链路文件写 agent-start/done 标记。服务端：GET /tasks/{id}/agents 聚合父链路 + 子链路文件成代理链（状态口径：委派以结束标记为准、无标记即进行中；模型子代理无结束信号时父任务运行中为进行中、否则未知）。命令台：新增子代理链路区，随 SSE 流防抖刷新；扁平链路也渲染 agent 标记。

cloud/console.html

@@ -248,6 +248,8 @@
   <div class="bar"><button id="btnContinueConfirm" class="primary">继续会话</button><span id="continueMsgSpan" class="muted"></span></div>
 </div>
 <pre id="detailBody" style="display:none"></pre>
+<h3>子代理链路</h3>
+<div id="agentBox" class="muted">点任务行查看详情后，这里显示子代理链路</div>
 <h3>实时链路</h3>
 <div id="traceBox" class="muted">点任务行查看详情后，这里显示过程链路</div>
 <div id="costBox"></div>
@@ -269,7 +271,7 @@ var $ = function (s) { return document.querySelector(s); };
 var KEY_STORE = "codex-console-key";
 var currentTask = null;
 var traceAbort = null;
-var TRACE_KIND = { exec: "命令", file: "文件", call: "调用", tool: "工具", message: "消息", reasoning: "思考", plan: "计划" };
+var TRACE_KIND = { exec: "命令", file: "文件", call: "调用", tool: "工具", message: "消息", reasoning: "思考", plan: "计划", "agent-start": "子代理", "agent-done": "子代理" };
 var TRACE_LIMIT = 1000;
 var TRACE_TERMINAL = ["completed", "failed", "interrupted", "merged", "merge-failed"];
 
@@ -485,6 +487,7 @@ async function loadTasks() {
 
 function stopTrace() {
   if (traceAbort) { try { traceAbort.abort(); } catch (e) {} traceAbort = null; }
+  if (agentTimer) { clearTimeout(agentTimer); agentTimer = null; }
 }
 function traceLine(e) {
   var k = TRACE_KIND[e.kind] || e.kind || "?";
@@ -496,6 +499,8 @@ function traceLine(e) {
   else if (e.kind === "tool") body = esc(e.server || "") + "/" + esc(e.tool || "") + " " + esc(e.status || "");
   else if (e.kind === "call") body = esc(e.name || "");
   else if (e.kind === "plan") body = esc(e.text || "");
+  else if (e.kind === "agent-start") body = "开始：" + esc(e.name || "") + (e.prompt ? "（" + esc(e.prompt) + "）" : "");
+  else if (e.kind === "agent-done") body = "结束：" + esc(e.name || "") + " " + esc(e.status || "");
   else body = esc(JSON.stringify(e).slice(0, 300));
   return "[" + k + "] " + body;
 }
@@ -512,6 +517,44 @@ function renderTrace(entries, note, doneStatus) {
   if (doneStatus) html += "<br><span class='muted'>链路已结束（" + esc(doneStatus) + "）</span>";
   box.innerHTML = html;
 }
+var AGENT_STATUS = { running: "进行中", completed: "已完成", failed: "失败", interrupted: "已中断", unknown: "未知" };
+var AGENT_KIND = { main: "主任务", delegate: "委派子任务", model: "模型子代理" };
+var AGENT_CALL_SHOWN = 50;
+var agentTimer = null;
+function renderAgents(data) {
+  var box = $("#agentBox");
+  var html = "";
+  if (!data) { box.innerHTML = "（暂无子代理链路）"; return; }
+  if (data.note) html += "<span class='err'>" + esc(data.note) + "</span><br>";
+  var agents = data.agents || [];
+  if (!agents.length) html += "（暂无子代理）";
+  agents.forEach(function (a) {
+    var st = AGENT_STATUS[a.status] || a.status || "?";
+    html += "<div style='margin:6px 0;padding:8px 10px;border:1px solid var(--border);border-radius:var(--radius);background:#fff'>";
+    html += "<b>" + esc(AGENT_KIND[a.kind] || a.kind || "") + "：</b>" + esc(a.name || "") +
+      " <span class='st-" + esc(a.status) + "'>" + esc(st) + "</span>" +
+      " ｜ 过程调用 " + (a.calls ? a.calls.length : 0) + " 条" +
+      (a.updated_ts ? " ｜ 最近活动 " + fmt(a.updated_ts / 1000) : "") + "<br>";
+    if (a.prompt) html += "<span class='muted'>任务：" + esc(a.prompt) + "</span><br>";
+    if (a.calls && a.calls.length) {
+      var shown = a.calls.slice(-AGENT_CALL_SHOWN);
+      if (a.calls.length > AGENT_CALL_SHOWN) html += "（仅显示最近 " + AGENT_CALL_SHOWN + " 条，共 " + a.calls.length + " 条）<br>";
+      html += shown.map(traceLine).join("<br>");
+    } else html += "<span class='muted'>（暂无过程调用）</span>";
+    html += "</div>";
+  });
+  box.innerHTML = html;
+}
+async function loadAgents(taskId) {
+  try {
+    var d = await api("/tasks/" + encodeURIComponent(taskId) + "/agents", "GET");
+    renderAgents(d);
+  } catch (e) { $("#agentBox").innerHTML = "<span class='err'>子代理链路加载失败：" + esc(e.message) + "</span>"; }
+}
+function scheduleAgents(taskId) {
+  if (agentTimer) clearTimeout(agentTimer);
+  agentTimer = setTimeout(function () { loadAgents(taskId); }, 1000);
+}
 async function startTrace(taskId, status) {
   stopTrace();
   var box = $("#traceBox");
@@ -561,10 +604,12 @@ async function startTrace(taskId, status) {
             entries.forEach(function (e, i) { index[e.id] = i; });
             note = m.note || "";
             renderTrace(entries, note, "");
+            scheduleAgents(taskId);
           } else if (m.type === "entry") {
             var e = m.entry;
             if (e.id in index) entries[index[e.id]] = e; else { index[e.id] = entries.length; entries.push(e); }
             renderTrace(entries, note, "");
+            scheduleAgents(taskId);
           } else if (m.type === "done") {
             done = true; doneStatus = m.status;
             renderTrace(entries, note, doneStatus);
@@ -618,6 +663,8 @@ async function showDetail(taskId) {
     $("#continueMsgSpan").textContent = "";
     $("#continueForm").style.display = (TRACE_TERMINAL.indexOf(t.status) >= 0 && t.status !== "merged") ? "block" : "none";
     startTrace(taskId, t.status);
+    $("#agentBox").innerHTML = "子代理链路加载中…";
+    loadAgents(taskId);
     loadFollowups(taskId);
   } catch (e) { $("#detail").innerHTML = "<span class='err'>加载失败：" + esc(e.message) + "</span>"; }
 }

cloud/server.py

@@ -184,6 +184,127 @@ def _read_trace_entries(path):
     except OSError:
         return []
     return entries
+
+
+AGENT_CALL_LIMIT = 1000
+
+
+def _read_agent_entries(path):
+    """读链路文件供子代理聚合：按 (thread, id) 去重，后到的完成态
+    覆盖先到的开始态，保首次顺序；坏行与无 id 行跳过；文件不
+    存在为空。同一 item id 在不同线程出现时不互相覆盖（模型内
+    子代理与主任务各有自己的线程）。"""
+    entries = []
+    index = {}
+    try:
+        with open(path, "r", encoding="utf-8") as f:
+            for line in f:
+                line = line.strip()
+                if not line:
+                    continue
+                try:
+                    entry = json.loads(line)
+                except ValueError:
+                    continue
+                if not isinstance(entry, dict) or "id" not in entry:
+                    continue
+                key = (entry.get("thread") or "", entry["id"])
+                if key in index:
+                    entries[index[key]] = entry
+                else:
+                    index[key] = len(entries)
+                    entries.append(entry)
+    except OSError:
+        return []
+    return entries
+
+
+def _latest_ts(values):
+    vals = [v for v in values if isinstance(v, (int, float))]
+    return max(vals) if vals else None
+
+
+def _agent_status_from_task(status):
+    return {"queued": "running", "running": "running",
+            "completed": "completed", "merged": "completed",
+            "failed": "failed", "merge-failed": "failed",
+            "interrupted": "interrupted"}.get(status, "unknown")
+
+
+def _build_agent_chain(task, trace_dir):
+    """任务 → 子代理链：主任务 + 模型内子代理（同文件多线程）+
+    委派子任务（父链路里的 agent-start/done 标记 + 子链路文件）。
+
+    状态诚实口径：委派子任务以 agent-done 标记为准，无标记即
+    进行中——委派进程与父任务相互独立，父任务结束不代表子任务
+    停；模型内子代理无明确结束信号，父任务运行中即进行中，
+    否则未知。无 thread 的旧条目一律归主任务。
+    """
+    parent_path = os.path.join(
+        trace_dir, _trace_file_name(task["id"]) + ".jsonl")
+    entries = _read_agent_entries(parent_path)
+    calls = [e for e in entries
+             if e.get("kind") not in ("agent-start", "agent-done")]
+    main_thread = None
+    for e in calls:
+        if e.get("thread"):
+            main_thread = e["thread"]
+            break
+    root_calls = [e for e in calls
+                  if not e.get("thread") or e.get("thread") == main_thread]
+    agents = [{
+        "id": "main", "name": "主任务", "kind": "main", "parent": None,
+        "status": _agent_status_from_task(task.get("status")),
+        "prompt": None, "trace": None,
+        "calls": root_calls[:AGENT_CALL_LIMIT],
+        "updated_ts": _latest_ts([e.get("ts") for e in root_calls]),
+    }]
+    task_running = task.get("status") in ("queued", "running")
+    threads = {}
+    for e in calls:
+        t = e.get("thread")
+        if t and t != main_thread:
+            threads.setdefault(t, []).append(e)
+    for t, es in threads.items():
+        agents.append({
+            "id": t, "name": "模型子代理 " + t[:12], "kind": "model",
+            "parent": "main",
+            "status": "running" if task_running else "unknown",
+            "prompt": None, "trace": None,
+            "calls": es[:AGENT_CALL_LIMIT],
+            "updated_ts": _latest_ts([e.get("ts") for e in es]),
+        })
+    starts = {}
+    dones = {}
+    for e in entries:
+        if e.get("kind") == "agent-start" and e.get("name"):
+            starts[e["name"]] = e
+        elif e.get("kind") == "agent-done" and e.get("name"):
+            dones[e["name"]] = e
+    for name, s in starts.items():
+        trace_name = s.get("trace") or dones.get(name, {}).get("trace")
+        child_calls = []
+        if trace_name:
+            child_path = os.path.join(
+                trace_dir, os.path.basename(trace_name))
+            child_calls = [e for e in _read_agent_entries(child_path)
+                           if e.get("kind") not in
+                           ("agent-start", "agent-done")]
+        done = dones.get(name)
+        status = "running"
+        if done and done.get("status") in (
+                "completed", "failed", "interrupted"):
+            status = done["status"]
+        agents.append({
+            "id": "delegate:" + name, "name": name, "kind": "delegate",
+            "parent": "main", "status": status,
+            "prompt": s.get("prompt"), "trace": trace_name,
+            "calls": child_calls[:AGENT_CALL_LIMIT],
+            "updated_ts": _latest_ts(
+                [e.get("ts") for e in child_calls] +
+                [s.get("ts"), done.get("ts") if done else None]),
+        })
+    return agents
 DEFAULT_SWEEP_THRESHOLD_SECONDS = 300
 # 限流默认值：每 IP / 每 API key 每分钟 120 次；环境变量
 # CLOUD_RATE_LIMIT_PER_MINUTE / CLOUD_RATE_LIMIT_WINDOW_SECONDS 可调。
@@ -1262,6 +1383,8 @@ class CloudControlPlaneHandler(BaseHTTPRequestHandler):
                     user_id, rest[: -len("/trace/stream")])
             elif rest.endswith("/trace") and method == "GET":
                 self._task_trace(user_id, rest[: -len("/trace")])
+            elif rest.endswith("/agents") and method == "GET":
+                self._task_agents(user_id, rest[: -len("/agents")])
             elif rest.endswith("/cancel") and method == "POST":
                 self._cancel_task(user_id, rest[: -len("/cancel")])
             elif rest.endswith("/merge") and method == "POST":
@@ -2471,6 +2594,27 @@ class CloudControlPlaneHandler(BaseHTTPRequestHandler):
         self._send_json(200, {"task_id": task_id, "status": task["status"],
                               "entries": entries, "note": note})
 
+    def _task_agents(self, user_id, task_id):
+        row = self._fetch_task(task_id)
+        if row is None:
+            self._send_json(404, {"error": "task not found"})
+            return
+        task = _task_to_dict(row)
+        with _auth_store(self.server.db_path) as store:
+            if not store.check_permission(user_id, task["project_id"], "read"):
+                self._send_json(403, {"error": "forbidden"})
+                return
+        worktree_host = task.get("worktree_host")
+        if worktree_host and worktree_host != socket.gethostname():
+            self._send_json(200, {"task_id": task_id, "status": task["status"],
+                                  "agents": [],
+                                  "note": ("链路文件在 worktree 主机 %s 上，本机读不到"
+                                           % worktree_host)})
+            return
+        agents = _build_agent_chain(task, _trace_dir_for(self.server))
+        self._send_json(200, {"task_id": task_id, "status": task["status"],
+                              "agents": agents, "note": ""})
+
     def _task_trace_stream(self, user_id, task_id):
         row = self._fetch_task(task_id)
         if row is None:

cloud/tests/test_console.py

@@ -64,7 +64,7 @@ class ConsoleTestCase(unittest.TestCase):
         self.assertIn("Codex 命令台", text)
         # 壳必须引用它实际调的接口，防 JS 与服务端路由漂移。
         for marker in ("/health", "/projects", "/tasks", "/workers",
-                       "X-API-Key"):
+                       "X-API-Key", "agentBox", "/agents"):
             self.assertIn(marker, text)
 
     def test_console_trailing_slash_same_page(self):

cloud/tests/test_task_trace.py

@@ -173,6 +173,79 @@ class TaskTraceTestCase(unittest.TestCase):
         self.assertEqual(status, 401)
         self.assertEqual(events, [])
 
+    def test_agents_auth_and_not_found(self):
+        status, _ = self._req(
+            "GET", "/tasks/%s/agents" % self.task_id)
+        self.assertEqual(status, 401)
+        status, _ = self._req(
+            "GET", "/tasks/%s/agents" % self.task_id, key=self.other_key)
+        self.assertEqual(status, 403)
+        status, _ = self._req(
+            "GET", "/tasks/nope/agents", key=self.owner_key)
+        self.assertEqual(status, 404)
+
+    def test_agents_chain_groups_calls_by_agent(self):
+        self._set_task(status="running")
+        self._write_trace([
+            json.dumps({"kind": "exec", "id": "c1", "thread": "th-main",
+                        "command": "make", "ts": 1000}),
+            json.dumps({"kind": "tool", "id": "t1", "thread": "th-sub",
+                        "server": "s", "tool": "read", "ts": 1001}),
+            json.dumps({"kind": "agent-start", "id": "agent:rev",
+                        "name": "rev", "prompt": "review code",
+                        "trace": "rev.jsonl", "ts": 1002}),
+            json.dumps({"kind": "agent-done", "id": "agent:rev:done",
+                        "name": "rev", "status": "completed",
+                        "trace": "rev.jsonl", "ts": 1004}),
+        ])
+        with open(os.path.join(self.trace_dir, "rev.jsonl"),
+                  "w", encoding="utf-8") as f:
+            f.write(json.dumps({"kind": "exec", "id": "c9",
+                                "command": "grep", "ts": 1003}) + "\n")
+        status, data = self._req(
+            "GET", "/tasks/%s/agents" % self.task_id, key=self.owner_key)
+        self.assertEqual(status, 200)
+        self.assertEqual(data["status"], "running")
+        by_kind = {a["kind"]: a for a in data["agents"]}
+        main = by_kind["main"]
+        self.assertEqual(main["status"], "running")
+        self.assertEqual([e["id"] for e in main["calls"]], ["c1"])
+        model = by_kind["model"]
+        self.assertEqual(model["status"], "running")
+        self.assertEqual([e["id"] for e in model["calls"]], ["t1"])
+        delegate = [a for a in data["agents"]
+                    if a["kind"] == "delegate"][0]
+        self.assertEqual(delegate["name"], "rev")
+        self.assertEqual(delegate["status"], "completed")
+        self.assertEqual(delegate["prompt"], "review code")
+        self.assertEqual([e["id"] for e in delegate["calls"]], ["c9"])
+        self.assertEqual(delegate["updated_ts"], 1004)
+
+    def test_agents_delegate_without_done_stays_running(self):
+        # 委派进程与父任务相互独立：父任务已结束、无结束标记时，
+        # 子任务仍算进行中（不能谎报它已中断）。
+        self._set_task(status="completed")
+        self._write_trace([
+            json.dumps({"kind": "agent-start", "id": "agent:rev",
+                        "name": "rev", "prompt": "review",
+                        "trace": "rev.jsonl", "ts": 1002}),
+        ])
+        status, data = self._req(
+            "GET", "/tasks/%s/agents" % self.task_id, key=self.owner_key)
+        self.assertEqual(status, 200)
+        delegate = [a for a in data["agents"]
+                    if a["kind"] == "delegate"][0]
+        self.assertEqual(delegate["status"], "running")
+        self.assertEqual(data["agents"][0]["status"], "completed")
+
+    def test_agents_missing_file_is_main_only(self):
+        status, data = self._req(
+            "GET", "/tasks/%s/agents" % self.task_id, key=self.owner_key)
+        self.assertEqual(status, 200)
+        self.assertEqual(len(data["agents"]), 1)
+        self.assertEqual(data["agents"][0]["kind"], "main")
+        self.assertEqual(data["agents"][0]["calls"], [])
+
 
 if __name__ == "__main__":
     unittest.main()

host.py

@@ -214,6 +214,8 @@ def _summarize_trace_item(method, params):
     返回 [] 表示该通知不进链路（userMessage 等）。
     ts 取通知的 completedAtMs/startedAtMs（毫秒 epoch），
     没有时为 None，服务端展示时按无时间处理。
+    thread 取通知的 threadId（模型内子代理与主任务同文件时，
+    服务端凭它把条目归属到不同代理；没有时为 None，归主任务）。
     """
     item = (params or {}).get("item")
     if not isinstance(item, dict):
@@ -221,8 +223,11 @@ def _summarize_trace_item(method, params):
     item_type = item.get("type")
     item_id = item.get("id") or ""
     ts = params.get("completedAtMs") or params.get("startedAtMs")
+    thread = params.get("threadId")
+    if not thread and isinstance(params.get("thread"), dict):
+        thread = params["thread"].get("id")
     if item_type == "commandExecution":
-        return [{"kind": "exec", "id": item_id, "ts": ts,
+        return [{"kind": "exec", "id": item_id, "ts": ts, "thread": thread,
                  "command": (item.get("command") or "")[:500],
                  "cwd": item.get("cwd") or "",
                  "exitCode": item.get("exitCode"),
@@ -235,6 +240,7 @@ def _summarize_trace_item(method, params):
             path = ch.get("path") or ""
             entries.append({"kind": "file",
                             "id": item_id + ":" + path, "ts": ts,
+                            "thread": thread,
                             "path": path, "change": ch.get("kind") or "",
                             "status": item.get("status") or ""})
         return entries
@@ -242,32 +248,60 @@ def _summarize_trace_item(method, params):
         text = item.get("text") or ""
         if not text:
             return []
-        return [{"kind": "message", "id": item_id, "ts": ts,
+        return [{"kind": "message", "id": item_id, "ts": ts, "thread": thread,
                  "phase": item.get("phase") or "", "text": text[:300]}]
     if item_type == "reasoning":
         summary = item.get("summary") or item.get("content") or []
         text = " ".join(s for s in summary if isinstance(s, str)).strip()
         if not text:
             return []
-        return [{"kind": "reasoning", "id": item_id, "ts": ts,
+        return [{"kind": "reasoning", "id": item_id, "ts": ts, "thread": thread,
                  "summary": text[:200]}]
     if item_type == "mcpToolCall":
-        return [{"kind": "tool", "id": item_id, "ts": ts,
+        return [{"kind": "tool", "id": item_id, "ts": ts, "thread": thread,
                  "server": item.get("server") or "",
                  "tool": item.get("tool") or "",
                  "status": item.get("status") or ""}]
     if item_type == "functionCallOutput":
-        return [{"kind": "call", "id": item_id, "ts": ts,
+        return [{"kind": "call", "id": item_id, "ts": ts, "thread": thread,
                  "name": item.get("name") or ""}]
     if item_type == "plan":
         text = item.get("text") or ""
         if not text:
             return []
-        return [{"kind": "plan", "id": item_id, "ts": ts,
+        return [{"kind": "plan", "id": item_id, "ts": ts, "thread": thread,
                  "text": text[:300]}]
     return []
 
 
+def _trace_file_path(state_path, task_name):
+    """链路文件路径：state 文件同目录下的 host-traces/<清洗后名字>.jsonl。
+
+    与 Server.set_trace_file、cloud 的 _trace_file_name 同款清洗，
+    三边算出同一名字，delegate 的父链路标记才能落进父任务文件。
+    """
+    safe = re.sub(r"[^A-Za-z0-9_.-]", "-", str(task_name))
+    return os.path.join(
+        os.path.dirname(os.path.abspath(state_path)),
+        "host-traces", safe + ".jsonl")
+
+
+def _append_trace_marker(state_path, task_name, entry):
+    """往另一任务的链路文件追加一条标记（delegate 向父链路报到用）。
+
+    尽力而为：目录建不出、写失败都不影响回合本身。父链路的
+    行数上限由属主进程自己的计数器管，这里不重复计数（标记
+    一轮至多两条，超限风险可忽略）。
+    """
+    try:
+        path = _trace_file_path(state_path, task_name)
+        os.makedirs(os.path.dirname(path), exist_ok=True)
+        with open(path, "a", encoding="utf-8") as f:
+            f.write(json.dumps(entry, ensure_ascii=False) + "\n")
+    except Exception:
+        pass
+
+
 class Server:
     """单个 app-server 进程，多 thread 并发。"""
 
@@ -302,12 +336,8 @@ class Server:
         时 trace_path 保持 None，不影响回合。
         """
         try:
-            safe = re.sub(r"[^A-Za-z0-9_.-]", "-", str(task_name))
+            self.trace_path = _trace_file_path(state_path, task_name)
-            trace_dir = os.path.join(
+            os.makedirs(os.path.dirname(self.trace_path), exist_ok=True)
-                os.path.dirname(os.path.abspath(state_path)),
-                "host-traces")
-            os.makedirs(trace_dir, exist_ok=True)
-            self.trace_path = os.path.join(trace_dir, safe + ".jsonl")
             self._trace_lines = 0
         except Exception:
             self.trace_path = None
@@ -2566,11 +2596,26 @@ def main():
                    "created_at": time.time(), "turns": []}
             state["tasks"][args.name] = sub
             save_state(args.state, state)
+            # 子代理链路：向父任务链路文件报到（开始 + 结束各一条），
+            # 服务端凭标记把子链路文件拼进父任务的代理链；子任务自己
+            # 的过程条目仍写它自己的链路文件（main 起动时按 --name 定）。
+            child_trace = (os.path.basename(srv.trace_path)
+                           if srv.trace_path else None)
+            _append_trace_marker(
+                args.state, args.parent_task,
+                {"kind": "agent-start", "id": "agent:" + args.name,
+                 "name": args.name, "prompt": (args.task or "")[:300],
+                 "trace": child_trace, "ts": int(time.time() * 1000)})
             result = run_task_turn(srv, state, sub, args.task,
                                    args.model, args.effort, args.sandbox,
                                    timeout=args.turn_timeout,
                                    interrupt_file=_interrupt_request_path(args.state, args.name))
             save_state(args.state, state)
+            _append_trace_marker(
+                args.state, args.parent_task,
+                {"kind": "agent-done", "id": "agent:" + args.name + ":done",
+                 "name": args.name, "status": sub["status"],
+                 "trace": child_trace, "ts": int(time.time() * 1000)})
             print(json.dumps({"sub_task": args.name, "status": sub["status"],
                               "text": result.get("text", "")},
                              indent=2, ensure_ascii=False))

tests/test_host_trace.py

@@ -6,6 +6,7 @@
 
 import json
 import os
+import shutil
 import sys
 import tempfile
 import unittest
@@ -130,6 +131,48 @@ class TraceFileTestCase(unittest.TestCase):
             self.assertEqual(len(lines), 1)
             self.assertEqual(json.loads(lines[0])["id"], "c1")
 
+    def test_summarize_carries_thread(self):
+        # 模型内子代理与主任务同文件时，服务端凭 thread 归属条目。
+        entries = _summarize_trace_item(
+            "item/completed",
+            {"item": {"type": "commandExecution", "id": "c1",
+                      "command": "ls"},
+             "threadId": "th-sub", "completedAtMs": 1700000000000})
+        self.assertEqual(entries[0]["thread"], "th-sub")
+        entries = _summarize_trace_item(
+            "item/completed",
+            {"item": {"type": "commandExecution", "id": "c2",
+                      "command": "ls"},
+             "completedAtMs": 1700000000000})
+        self.assertIsNone(entries[0]["thread"])
+
+    def test_append_trace_marker_to_parent_file(self):
+        # delegate 向父链路报到：路径清洗与 set_trace_file 一致，
+        # 写失败不抛（尽力而为，不影响回合）。
+        from host import _append_trace_marker, _trace_file_path
+        with tempfile.TemporaryDirectory() as d:
+            state_path = os.path.join(d, "host-state.json")
+            self.assertEqual(
+                _trace_file_path(state_path, "abc/def?id=1"),
+                os.path.join(d, "host-traces", "abc-def-id-1.jsonl"))
+            _append_trace_marker(
+                state_path, "parent task!",
+                {"kind": "agent-start", "id": "agent:rev",
+                 "name": "rev", "prompt": "review"})
+            path = os.path.join(d, "host-traces", "parent-task-.jsonl")
+            with open(path, encoding="utf-8") as f:
+                entry = json.loads(f.read().strip())
+            self.assertEqual(entry["kind"], "agent-start")
+            self.assertEqual(entry["name"], "rev")
+            # 目录被文件占住时也不抛。
+            blocker = os.path.join(d, "host-traces")
+            shutil.rmtree(blocker)
+            with open(blocker, "w", encoding="utf-8") as f:
+                f.write("x")
+            _append_trace_marker(state_path, "parent task!",
+                                 {"kind": "agent-done", "id": "agent:rev:done",
+                                  "name": "rev", "status": "completed"})
+
 
 if __name__ == "__main__":
     unittest.main()