diff --git a/AGENTS.md b/AGENTS.md
index ee05ac7..153f5b3 100644
--- a/AGENTS.md
+++ b/AGENTS.md
@@ -69,7 +69,10 @@ docker-compose up -d                   # AgentKit + Redis + PostgreSQL
                 （问候、身份、事实问答、数学、翻译；由 _TOOL_CONTEXT_RE 守护）
        默认: -> REACT（LLM 在 agent 循环中自主决定工具使用）
   -> ExecutionMode: DIRECT_CHAT / REACT / SKILL_REACT / REWOO / REFLEXION / PLAN_EXEC / TEAM_COLLAB
-     （chat handler 当前支持 DIRECT_CHAT、REACT、SKILL_REACT；其余抛出 "not yet supported"）
+     （chat handler 支持 DIRECT_CHAT、REACT、SKILL_REACT、PLAN_EXEC；
+       TEAM_COLLAB 通过 @team 前缀路由到 TeamOrchestrator（R7，不回退到 REACT）；
+       ExecutionMode.TEAM_COLLAB 非前缀触发时向用户报错并提示使用 @team；
+       REWOO / REFLEXION-as-mode 暂时回退到 REACT（RV10 deferred））
 ```
 
 **注意**：旧的 3 层 `CostAwareRouter`（含 `RegexRules` / `HeuristicClassifier` / `SemanticRouter` / `Vickrey Auction`）已被 `RequestPreprocessor` 替换。`IntentRouter`（`router/intent.py`）存在但未接入 chat 流程。`AuctionHouse`（Vickrey 拍卖）位于 `marketplace/auction.py`（属于 marketplace 子系统，非路由）。
diff --git a/src/agentkit/server/routes/chat.py b/src/agentkit/server/routes/chat.py
index 269d8bd..354236b 100644
--- a/src/agentkit/server/routes/chat.py
+++ b/src/agentkit/server/routes/chat.py
@@ -1367,16 +1367,40 @@ async def _handle_chat_message(
         )
         return
 
-    # Handle advanced execution modes: REWOO/REFLEXION/TEAM_COLLAB
-    # still fall back to REACT with a warning. PLAN_EXEC is handled above.
+    # Handle advanced execution modes.
+    # R7 (U9): TEAM_COLLAB surfaces failure to the user — does NOT fall back to
+    # REACT. The @team prefix route (_execute_team_collab above) invokes
+    # TeamOrchestrator directly; reaching this block means TEAM_COLLAB was set
+    # by RequestPreprocessor/skill routing without the @team prefix, so we
+    # guide the user to use @team instead of silently degrading.
+    # RV10 deferred: REWOO/REFLEXION-as-mode still fall back to REACT.
+    if routing.execution_mode == ExecutionMode.TEAM_COLLAB:
+        logger.info(
+            "TEAM_COLLAB execution_mode reached without @team prefix for "
+            "session %s; surfacing error to user (R7, no REACT fall-back)",
+            session_id,
+        )
+        await websocket.send_json(
+            {
+                "type": "error",
+                "data": {
+                    "message": (
+                        "TEAM_COLLAB 模式需要通过 @team 前缀触发。"
+                        "请在消息开头添加 @team 或指定团队模板，"
+                        "例如：@team:dev_team 开发用户登录功能"
+                    )
+                },
+            }
+        )
+        return
     if routing.execution_mode not in (
         ExecutionMode.REACT,
         ExecutionMode.SKILL_REACT,
         ExecutionMode.PLAN_EXEC,
     ):
         logger.warning(
-            f"Execution mode {routing.execution_mode.value} not implemented "
-            f"in chat WebSocket path, falling back to REACT"
+            f"Execution mode {routing.execution_mode.value} is deferred (RV10), "
+            f"falling back to REACT"
         )
 
     # Execute Agent with streaming
diff --git a/tests/unit/test_team_collab_routing.py b/tests/unit/test_team_collab_routing.py
new file mode 100644
index 0000000..646772a
--- /dev/null
+++ b/tests/unit/test_team_collab_routing.py
@@ -0,0 +1,594 @@
+"""Unit tests for TEAM_COLLAB routing (U9, R7).
+
+Verifies that ``ExecutionMode.TEAM_COLLAB`` reached via the non-@team-prefix
+path (RequestPreprocessor / skill routing) surfaces an error to the user
+instead of silently falling back to REACT. The @team prefix itself is handled
+earlier by ``_execute_team_collab`` and is out of scope here — this test only
+covers the routing decision at the fall-back block.
+
+REWOO / REFLEXION-as-mode keep their deferred REACT fall-back (RV10).
+"""
+
+from __future__ import annotations
+
+import logging
+from pathlib import Path
+from unittest.mock import AsyncMock, MagicMock
+
+import pytest
+
+from agentkit.chat.skill_routing import ExecutionMode, SkillRoutingResult
+
+# ---------------------------------------------------------------------------
+# Fixtures and helpers (mirrors test_chat_plan_exec_ws.py patterns)
+# ---------------------------------------------------------------------------
+
+
+REPO_ROOT = Path(__file__).resolve().parents[2]
+AGENTS_MD = REPO_ROOT / "AGENTS.md"
+
+TEAM_COLLAB_ERROR_HINT = "@team"
+
+
+@pytest.fixture
+def app_with_chat():
+    """Create a FastAPI app with Chat routes and mocked dependencies."""
+    from fastapi import FastAPI
+
+    from agentkit.server.routes.chat import router
+
+    app = FastAPI()
+    app.include_router(router, prefix="/api/v1")
+
+    from agentkit.session.manager import SessionManager
+    from agentkit.session.store import InMemorySessionStore
+
+    app.state.session_manager = SessionManager(store=InMemorySessionStore())
+    app.state.llm_gateway = MagicMock()
+    app.state.agent_pool = MagicMock()
+    app.state.server_config = MagicMock()
+    app.state.server_config.api_key = None
+    app.state.server_config.plan_exec = {}
+    return app
+
+
+def _make_routing(
+    execution_mode: ExecutionMode = ExecutionMode.REACT,
+    tools: list | None = None,
+    system_prompt: str | None = None,
+) -> SkillRoutingResult:
+    """Build a minimal SkillRoutingResult for testing."""
+    return SkillRoutingResult(
+        execution_mode=execution_mode,
+        tools=tools or [],
+        clean_content="test message",
+        model="default",
+        agent_name="test-agent",
+        system_prompt=system_prompt,
+        skill_name=None,
+    )
+
+
+def _make_websocket_mock(app) -> MagicMock:
+    """Build a mock WebSocket with app.state and async send_json."""
+    ws = MagicMock()
+    ws.app = app
+    ws.send_json = AsyncMock()
+    return ws
+
+
+def _make_agent_mock() -> MagicMock:
+    """Build a mock Agent with _tool_registry and _react_engine."""
+    agent = MagicMock()
+    agent.name = "test-agent"
+    agent._tool_registry = MagicMock()
+    agent._tool_registry.list_tools.return_value = []
+    agent._system_prompt = None
+    # _react_engine is None to force the code path that creates a new engine
+    agent._react_engine = None
+    agent.get_model.return_value = "default"
+    return agent
+
+
+def _make_session_manager_mock() -> MagicMock:
+    """Build a mock SessionManager with async methods."""
+    sm = MagicMock()
+    session = MagicMock()
+    session.agent_name = "test-agent"
+    session.status = "active"
+    sm.get_session = AsyncMock(return_value=session)
+    sm.get_chat_messages = AsyncMock(return_value=[])
+    sm.append_message = AsyncMock()
+    return sm
+
+
+def _setup_routing(app, routing: SkillRoutingResult, agent: MagicMock) -> None:
+    """Wire up app.state so _handle_chat_message finds the right routing."""
+    app.state.agent_pool.get_agent.return_value = agent
+    app.state.request_preprocessor = MagicMock()
+    app.state.request_preprocessor.preprocess = AsyncMock(return_value=routing)
+
+
+class _ToolStub:
+    """Minimal tool stub with a name attribute (for tool_names logging)."""
+
+    def __init__(self, name: str) -> None:
+        self.name = name
+
+
+def _make_stub_engine_class(
+    constructed_engines: list,
+    stream_calls: list,
+) -> type:
+    """Build a stub ReActEngine subclass that records construction + stream calls.
+
+    The stub is a valid async generator (uses ``return; yield`` per project rule
+    so Python treats it as an async generator even when the body returns first).
+    """
+
+    class _StubEngine:
+        def __init__(self, **kwargs) -> None:
+            constructed_engines.append(self)
+            self._phase_policy = kwargs.get("phase_policy")
+            self._current_phase = (
+                kwargs.get("phase_policy").start_phase if kwargs.get("phase_policy") else None
+            )
+
+        @property
+        def current_phase(self):
+            return self._current_phase
+
+        def reset(self) -> None:
+            pass
+
+        async def execute_stream(self, **kwargs):
+            stream_calls.append(kwargs)
+            return
+            yield  # async generator marker (project rule)
+
+    return _StubEngine
+
+
+def _sent_messages(ws: MagicMock) -> list[dict]:
+    return [call.args[0] for call in ws.send_json.call_args_list]
+
+
+# ---------------------------------------------------------------------------
+# Happy path — TEAM_COLLAB (non-prefix) surfaces error, no REACT fall-back
+# ---------------------------------------------------------------------------
+
+
+@pytest.mark.asyncio
+async def test_team_collab_non_prefix_sends_error_and_aborts(app_with_chat):
+    """Happy path: TEAM_COLLAB without @team prefix → error with @team guidance,
+    execution aborted (no ReActEngine.execute_stream call)."""
+    from agentkit.server.routes import chat as chat_module
+
+    agent = _make_agent_mock()
+    routing = _make_routing(execution_mode=ExecutionMode.TEAM_COLLAB)
+    _setup_routing(app_with_chat, routing, agent)
+
+    sm = _make_session_manager_mock()
+    ws = _make_websocket_mock(app_with_chat)
+
+    constructed: list = []
+    stream_calls: list = []
+    stub_engine = _make_stub_engine_class(constructed, stream_calls)
+
+    with pytest.MonkeyPatch().context() as mp:
+        mp.setattr(chat_module, "ReActEngine", stub_engine)
+
+        await chat_module._handle_chat_message(
+            websocket=ws,
+            session_id="test-session",
+            content="test",
+            sm=sm,
+            cancellation_token=MagicMock(),
+            pending_replies={},
+            pending_confirmations=None,
+        )
+
+    sent = _sent_messages(ws)
+    error_messages = [m for m in sent if m.get("type") == "error"]
+    assert len(error_messages) == 1, f"expected exactly one error, got {sent}"
+    message = error_messages[0]["data"]["message"]
+    assert TEAM_COLLAB_ERROR_HINT in message, f"error message must mention @team: {message}"
+    # No REACT engine was constructed for execution (fall-back NOT taken)
+    assert len(constructed) == 0, "ReActEngine should not be constructed for TEAM_COLLAB"
+    assert len(stream_calls) == 0, "execute_stream must not be called for TEAM_COLLAB"
+
+
+# ---------------------------------------------------------------------------
+# Edge cases — other modes do NOT trigger the TEAM_COLLAB error block
+# ---------------------------------------------------------------------------
+
+
+@pytest.mark.asyncio
+async def test_react_mode_continues_without_team_collab_error(app_with_chat):
+    """Edge: REACT mode → no TEAM_COLLAB error, normal execution continues."""
+    from agentkit.server.routes import chat as chat_module
+
+    agent = _make_agent_mock()
+    routing = _make_routing(execution_mode=ExecutionMode.REACT)
+    _setup_routing(app_with_chat, routing, agent)
+
+    sm = _make_session_manager_mock()
+    ws = _make_websocket_mock(app_with_chat)
+
+    constructed: list = []
+    stream_calls: list = []
+    stub_engine = _make_stub_engine_class(constructed, stream_calls)
+
+    with pytest.MonkeyPatch().context() as mp:
+        mp.setattr(chat_module, "ReActEngine", stub_engine)
+
+        await chat_module._handle_chat_message(
+            websocket=ws,
+            session_id="test-session",
+            content="test",
+            sm=sm,
+            cancellation_token=MagicMock(),
+            pending_replies={},
+            pending_confirmations=None,
+        )
+
+    sent = _sent_messages(ws)
+    team_errors = [
+        m
+        for m in sent
+        if m.get("type") == "error"
+        and TEAM_COLLAB_ERROR_HINT in m.get("data", {}).get("message", "")
+    ]
+    assert len(team_errors) == 0, "REACT must not trigger TEAM_COLLAB error"
+    # REACT executes via the fallback path → engine constructed + stream called
+    assert len(stream_calls) == 1, "REACT should invoke execute_stream once"
+
+
+@pytest.mark.asyncio
+async def test_skill_react_mode_continues_without_team_collab_error(app_with_chat):
+    """Edge: SKILL_REACT mode → no TEAM_COLLAB error, normal execution continues."""
+    from agentkit.server.routes import chat as chat_module
+
+    agent = _make_agent_mock()
+    routing = _make_routing(execution_mode=ExecutionMode.SKILL_REACT)
+    _setup_routing(app_with_chat, routing, agent)
+
+    sm = _make_session_manager_mock()
+    ws = _make_websocket_mock(app_with_chat)
+
+    constructed: list = []
+    stream_calls: list = []
+    stub_engine = _make_stub_engine_class(constructed, stream_calls)
+
+    with pytest.MonkeyPatch().context() as mp:
+        mp.setattr(chat_module, "ReActEngine", stub_engine)
+
+        await chat_module._handle_chat_message(
+            websocket=ws,
+            session_id="test-session",
+            content="test",
+            sm=sm,
+            cancellation_token=MagicMock(),
+            pending_replies={},
+            pending_confirmations=None,
+        )
+
+    sent = _sent_messages(ws)
+    team_errors = [
+        m
+        for m in sent
+        if m.get("type") == "error"
+        and TEAM_COLLAB_ERROR_HINT in m.get("data", {}).get("message", "")
+    ]
+    assert len(team_errors) == 0, "SKILL_REACT must not trigger TEAM_COLLAB error"
+    assert len(stream_calls) == 1, "SKILL_REACT should invoke execute_stream once"
+
+
+@pytest.mark.asyncio
+async def test_plan_exec_mode_does_not_trigger_fallback_block(app_with_chat):
+    """Edge: PLAN_EXEC → handled earlier, fall-back block must not trigger."""
+    from agentkit.server.routes import chat as chat_module
+
+    app_with_chat.state.server_config.plan_exec = {}
+
+    agent = _make_agent_mock()
+    routing = _make_routing(execution_mode=ExecutionMode.PLAN_EXEC)
+    _setup_routing(app_with_chat, routing, agent)
+
+    sm = _make_session_manager_mock()
+    sm.get_chat_messages = AsyncMock(return_value=[{"role": "user", "content": "test"}])
+    ws = _make_websocket_mock(app_with_chat)
+
+    constructed: list = []
+    stream_calls: list = []
+    stub_engine = _make_stub_engine_class(constructed, stream_calls)
+
+    with pytest.MonkeyPatch().context() as mp:
+        mp.setattr(chat_module, "ReActEngine", stub_engine)
+
+        await chat_module._handle_chat_message(
+            websocket=ws,
+            session_id="test-session",
+            content="test",
+            sm=sm,
+            cancellation_token=MagicMock(),
+            pending_replies={},
+            pending_confirmations=None,
+        )
+
+    sent = _sent_messages(ws)
+    team_errors = [
+        m
+        for m in sent
+        if m.get("type") == "error"
+        and TEAM_COLLAB_ERROR_HINT in m.get("data", {}).get("message", "")
+    ]
+    assert len(team_errors) == 0, "PLAN_EXEC must not trigger TEAM_COLLAB error"
+    # PLAN_EXEC builds a phase engine and runs execute_stream
+    assert len(stream_calls) == 1, "PLAN_EXEC should invoke execute_stream once"
+
+
+@pytest.mark.asyncio
+async def test_rewoo_falls_back_to_react_with_deferred_log(app_with_chat, caplog):
+    """Edge: REWOO → falls back to REACT with deferred (RV10) log, NOT a user error."""
+    from agentkit.server.routes import chat as chat_module
+
+    agent = _make_agent_mock()
+    routing = _make_routing(execution_mode=ExecutionMode.REWOO)
+    _setup_routing(app_with_chat, routing, agent)
+
+    sm = _make_session_manager_mock()
+    ws = _make_websocket_mock(app_with_chat)
+
+    constructed: list = []
+    stream_calls: list = []
+    stub_engine = _make_stub_engine_class(constructed, stream_calls)
+
+    with pytest.MonkeyPatch().context() as mp:
+        mp.setattr(chat_module, "ReActEngine", stub_engine)
+        with caplog.at_level(logging.WARNING, logger="agentkit.server.routes.chat"):
+            await chat_module._handle_chat_message(
+                websocket=ws,
+                session_id="test-session",
+                content="test",
+                sm=sm,
+                cancellation_token=MagicMock(),
+                pending_replies={},
+                pending_confirmations=None,
+            )
+
+    # REWOO falls back to REACT — execute_stream IS called
+    assert len(stream_calls) == 1, "REWOO should fall back to REACT execute_stream"
+    # A deferred (RV10) warning was logged
+    deferred_logs = [r for r in caplog.records if "deferred (RV10)" in r.message]
+    assert len(deferred_logs) == 1, f"expected deferred RV10 log, got {caplog.records}"
+    assert "rewoo" in deferred_logs[0].message.lower()
+    # No TEAM_COLLAB-style error was sent to the user
+    sent = _sent_messages(ws)
+    team_errors = [
+        m
+        for m in sent
+        if m.get("type") == "error"
+        and TEAM_COLLAB_ERROR_HINT in m.get("data", {}).get("message", "")
+    ]
+    assert len(team_errors) == 0, "REWOO fall-back must not surface a TEAM_COLLAB error"
+
+
+@pytest.mark.asyncio
+async def test_reflexion_falls_back_to_react_with_deferred_log(app_with_chat, caplog):
+    """Edge: REFLEXION → falls back to REACT with deferred (RV10) log, NOT a user error."""
+    from agentkit.server.routes import chat as chat_module
+
+    agent = _make_agent_mock()
+    routing = _make_routing(execution_mode=ExecutionMode.REFLEXION)
+    _setup_routing(app_with_chat, routing, agent)
+
+    sm = _make_session_manager_mock()
+    ws = _make_websocket_mock(app_with_chat)
+
+    constructed: list = []
+    stream_calls: list = []
+    stub_engine = _make_stub_engine_class(constructed, stream_calls)
+
+    with pytest.MonkeyPatch().context() as mp:
+        mp.setattr(chat_module, "ReActEngine", stub_engine)
+        with caplog.at_level(logging.WARNING, logger="agentkit.server.routes.chat"):
+            await chat_module._handle_chat_message(
+                websocket=ws,
+                session_id="test-session",
+                content="test",
+                sm=sm,
+                cancellation_token=MagicMock(),
+                pending_replies={},
+                pending_confirmations=None,
+            )
+
+    assert len(stream_calls) == 1, "REFLEXION should fall back to REACT execute_stream"
+    deferred_logs = [r for r in caplog.records if "deferred (RV10)" in r.message]
+    assert len(deferred_logs) == 1, f"expected deferred RV10 log, got {caplog.records}"
+    assert "reflexion" in deferred_logs[0].message.lower()
+    sent = _sent_messages(ws)
+    team_errors = [
+        m
+        for m in sent
+        if m.get("type") == "error"
+        and TEAM_COLLAB_ERROR_HINT in m.get("data", {}).get("message", "")
+    ]
+    assert len(team_errors) == 0, "REFLEXION fall-back must not surface a TEAM_COLLAB error"
+
+
+@pytest.mark.asyncio
+async def test_direct_chat_does_not_trigger_fallback_block(app_with_chat, monkeypatch):
+    """Edge: DIRECT_CHAT → handled earlier, fall-back block not reached."""
+    from agentkit.server.routes import chat as chat_module
+
+    agent = _make_agent_mock()
+    routing = _make_routing(execution_mode=ExecutionMode.DIRECT_CHAT)
+    _setup_routing(app_with_chat, routing, agent)
+
+    sm = _make_session_manager_mock()
+    ws = _make_websocket_mock(app_with_chat)
+
+    # DIRECT_CHAT calls _resolve_ws_dept_context + llm_gateway.chat
+    monkeypatch.setattr(
+        chat_module,
+        "_resolve_ws_dept_context",
+        AsyncMock(return_value=(None, [], None)),
+    )
+    response = MagicMock()
+    response.content = "direct reply"
+    app_with_chat.state.llm_gateway.chat = AsyncMock(return_value=response)
+
+    constructed: list = []
+    stream_calls: list = []
+    stub_engine = _make_stub_engine_class(constructed, stream_calls)
+
+    with pytest.MonkeyPatch().context() as mp:
+        mp.setattr(chat_module, "ReActEngine", stub_engine)
+
+        await chat_module._handle_chat_message(
+            websocket=ws,
+            session_id="test-session",
+            content="test",
+            sm=sm,
+            cancellation_token=MagicMock(),
+            pending_replies={},
+            pending_confirmations=None,
+        )
+
+    sent = _sent_messages(ws)
+    team_errors = [
+        m
+        for m in sent
+        if m.get("type") == "error"
+        and TEAM_COLLAB_ERROR_HINT in m.get("data", {}).get("message", "")
+    ]
+    assert len(team_errors) == 0, "DIRECT_CHAT must not trigger TEAM_COLLAB error"
+    # DIRECT_CHAT returns before the engine block — no engine, no stream
+    assert len(constructed) == 0, "DIRECT_CHAT should not construct ReActEngine"
+    assert len(stream_calls) == 0, "DIRECT_CHAT should not call execute_stream"
+    # DIRECT_CHAT emits a final_answer
+    final_answers = [m for m in sent if m.get("type") == "final_answer"]
+    assert len(final_answers) == 1
+
+
+# ---------------------------------------------------------------------------
+# Error and failure paths — ordering + no side effects
+# ---------------------------------------------------------------------------
+
+
+@pytest.mark.asyncio
+async def test_team_collab_error_sent_before_any_engine_execution(app_with_chat):
+    """Failure path: error is sent and execution aborts — ReActEngine is never
+    constructed (engine construction happens after the TEAM_COLLAB return)."""
+    from agentkit.server.routes import chat as chat_module
+
+    agent = _make_agent_mock()
+    routing = _make_routing(execution_mode=ExecutionMode.TEAM_COLLAB)
+    _setup_routing(app_with_chat, routing, agent)
+
+    sm = _make_session_manager_mock()
+    ws = _make_websocket_mock(app_with_chat)
+
+    constructed: list = []
+    stream_calls: list = []
+    stub_engine = _make_stub_engine_class(constructed, stream_calls)
+
+    with pytest.MonkeyPatch().context() as mp:
+        mp.setattr(chat_module, "ReActEngine", stub_engine)
+
+        await chat_module._handle_chat_message(
+            websocket=ws,
+            session_id="test-session",
+            content="test",
+            sm=sm,
+            cancellation_token=MagicMock(),
+            pending_replies={},
+            pending_confirmations=None,
+        )
+
+    # Engine never constructed → execute_stream could not have run before error
+    assert len(constructed) == 0, "engine must not be constructed before error"
+    assert len(stream_calls) == 0, "execute_stream must not run before error"
+    sent = _sent_messages(ws)
+    # The error was sent (ordering verified: error present, no engine work done)
+    assert any(m.get("type") == "error" for m in sent), "error must be sent"
+
+
+@pytest.mark.asyncio
+async def test_team_collab_does_not_mutate_routing_tools_or_system_prompt(app_with_chat):
+    """Failure path: TEAM_COLLAB error path does not mutate routing.tools or
+    routing.system_prompt (no side effects before the early return)."""
+    from agentkit.server.routes import chat as chat_module
+
+    agent = _make_agent_mock()
+    sentinel_tool = _ToolStub("sentinel")
+    routing = _make_routing(
+        execution_mode=ExecutionMode.TEAM_COLLAB,
+        tools=[sentinel_tool],
+        system_prompt="original-system-prompt",
+    )
+    _setup_routing(app_with_chat, routing, agent)
+
+    sm = _make_session_manager_mock()
+    ws = _make_websocket_mock(app_with_chat)
+
+    tools_before_id = id(routing.tools)
+    tools_before_copy = list(routing.tools)
+    system_prompt_before = routing.system_prompt
+
+    constructed: list = []
+    stream_calls: list = []
+    stub_engine = _make_stub_engine_class(constructed, stream_calls)
+
+    with pytest.MonkeyPatch().context() as mp:
+        mp.setattr(chat_module, "ReActEngine", stub_engine)
+
+        await chat_module._handle_chat_message(
+            websocket=ws,
+            session_id="test-session",
+            content="test",
+            sm=sm,
+            cancellation_token=MagicMock(),
+            pending_replies={},
+            pending_confirmations=None,
+        )
+
+    # routing.tools not replaced (same object) and not mutated (same contents)
+    assert id(routing.tools) == tools_before_id, "routing.tools must not be replaced"
+    assert routing.tools == tools_before_copy, "routing.tools contents must be unchanged"
+    assert routing.tools[0] is sentinel_tool, "routing.tools[0] identity must be unchanged"
+    assert routing.system_prompt == system_prompt_before, "system_prompt must be unchanged"
+
+
+# ---------------------------------------------------------------------------
+# Integration — AGENTS.md reflects actual behavior (regression guard)
+# ---------------------------------------------------------------------------
+
+
+def test_agents_md_contains_updated_team_collab_wording():
+    """Integration: AGENTS.md documents TEAM_COLLAB routing + R7 (no REACT fall-back)."""
+    text = AGENTS_MD.read_text(encoding="utf-8")
+    assert "TEAM_COLLAB 通过 @team 前缀路由到 TeamOrchestrator（R7，不回退到 REACT）" in text, (
+        "AGENTS.md must document TEAM_COLLAB @team routing with R7 no-fall-back"
+    )
+    assert "ExecutionMode.TEAM_COLLAB 非前缀触发时向用户报错并提示使用 @team" in text, (
+        "AGENTS.md must document the non-prefix TEAM_COLLAB error path"
+    )
+    assert "REWOO / REFLEXION-as-mode 暂时回退到 REACT（RV10 deferred）" in text, (
+        "AGENTS.md must document REWOO/REFLEXION-as-mode deferred fall-back"
+    )
+
+
+def test_agents_md_no_longer_claims_not_yet_supported_for_chat_handler():
+    """Integration: AGENTS.md no longer carries the stale '抛出 not yet supported' claim."""
+    text = AGENTS_MD.read_text(encoding="utf-8")
+    # The stale phrase attributed the chat handler as raising "not yet supported"
+    # for unsupported modes. That is no longer true (PLAN_EXEC + TEAM_COLLAB
+    # routing are wired; REWOO/REFLEXION fall back).
+    assert '抛出 "not yet supported"' not in text, (
+        "AGENTS.md must not claim chat handler raises 'not yet supported'"
+    )
+    assert "其余抛出" not in text, (
+        "AGENTS.md must not claim the remaining modes raise (they route/fall back)"
+    )