feat(mcp): add preset setup and capability mentions

tests/agent/test_mcp_connection.py

@@ -2,12 +2,39 @@
 
 from __future__ import annotations
 
+import asyncio
+from contextlib import AsyncExitStack
+from typing import Any
 from unittest.mock import MagicMock
 
 import pytest
 
 from nanobot.agent.loop import AgentLoop
+from nanobot.agent.tools import mcp as mcp_runtime
+from nanobot.agent.tools.base import Tool
 from nanobot.bus.queue import MessageBus
+from nanobot.config.loader import load_config, save_config
+from nanobot.config.schema import MCPServerConfig
+
+
+class _FakeMcpTool(Tool):
+    def __init__(self, name: str) -> None:
+        self._name = name
+
+    @property
+    def name(self) -> str:
+        return self._name
+
+    @property
+    def description(self) -> str:
+        return "fake MCP tool"
+
+    @property
+    def parameters(self) -> dict[str, Any]:
+        return {"type": "object", "properties": {}}
+
+    async def execute(self, **_kwargs: Any) -> str:
+        return "ok"
 
 
 def _make_loop(tmp_path, *, mcp_servers: dict | None = None) -> AgentLoop:
@@ -42,3 +69,152 @@ async def test_connect_mcp_retries_when_no_servers_connect(tmp_path, monkeypatch
     assert attempts == 2
     assert loop._mcp_connected is False
     assert loop._mcp_stacks == {}
+
+
+@pytest.mark.asyncio
+async def test_reload_mcp_servers_adds_and_removes_tools_without_restart(
+    tmp_path,
+    monkeypatch: pytest.MonkeyPatch,
+):
+    config_path = tmp_path / "config.json"
+    monkeypatch.setattr("nanobot.config.loader._current_config_path", config_path)
+    config = load_config()
+    config.tools.mcp_servers["browserbase"] = MCPServerConfig(
+        type="stdio",
+        command="browserbase-mcp",
+    )
+    save_config(config)
+
+    closed: list[str] = []
+
+    async def _mark_closed(name: str) -> None:
+        closed.append(name)
+
+    async def _fake_connect(servers, registry):
+        stacks = {}
+        for name in servers:
+            registry.register(_FakeMcpTool(f"mcp_{name}_navigate"))
+            stack = AsyncExitStack()
+            await stack.__aenter__()
+            stack.push_async_callback(_mark_closed, name)
+            stacks[name] = stack
+        return stacks
+
+    monkeypatch.setattr("nanobot.agent.tools.mcp.connect_mcp_servers", _fake_connect)
+    loop = _make_loop(tmp_path, mcp_servers={})
+
+    added = await mcp_runtime.reload_servers(loop, loop.tools)
+
+    assert added["ok"] is True
+    assert added["added"] == ["browserbase"]
+    assert loop.tools.has("mcp_browserbase_navigate")
+    assert "browserbase" in loop._mcp_stacks
+
+    config = load_config()
+    del config.tools.mcp_servers["browserbase"]
+    save_config(config)
+
+    removed = await mcp_runtime.reload_servers(loop, loop.tools)
+
+    assert removed["ok"] is True
+    assert removed["removed"] == ["browserbase"]
+    assert not loop.tools.has("mcp_browserbase_navigate")
+    assert "browserbase" not in loop._mcp_stacks
+    assert closed == ["browserbase"]
+
+
+@pytest.mark.asyncio
+async def test_request_mcp_reload_reaches_runtime_control_without_restart(
+    tmp_path,
+    monkeypatch: pytest.MonkeyPatch,
+):
+    config_path = tmp_path / "config.json"
+    monkeypatch.setattr("nanobot.config.loader._current_config_path", config_path)
+    config = load_config()
+    config.tools.mcp_servers["browserbase"] = MCPServerConfig(
+        type="stdio",
+        command="browserbase-mcp",
+    )
+    save_config(config)
+
+    closed: list[str] = []
+
+    async def _mark_closed(name: str) -> None:
+        closed.append(name)
+
+    async def _fake_connect(servers, registry):
+        stacks = {}
+        for name in servers:
+            registry.register(_FakeMcpTool(f"mcp_{name}_navigate"))
+            stack = AsyncExitStack()
+            await stack.__aenter__()
+            stack.push_async_callback(_mark_closed, name)
+            stacks[name] = stack
+        return stacks
+
+    monkeypatch.setattr("nanobot.agent.tools.mcp.connect_mcp_servers", _fake_connect)
+    loop = _make_loop(tmp_path, mcp_servers={})
+
+    async def _handle_one_runtime_control() -> None:
+        msg = await loop.bus.consume_inbound()
+        handled = await mcp_runtime.handle_runtime_control(loop, msg, loop.tools)
+        assert handled is True
+
+    consumer = asyncio.create_task(_handle_one_runtime_control())
+    result = await mcp_runtime.request_mcp_reload(loop.bus, timeout=2.0)
+    await consumer
+
+    assert result["ok"] is True
+    assert result["added"] == ["browserbase"]
+    assert result["requires_restart"] is False
+    assert loop.tools.has("mcp_browserbase_navigate")
+
+    config = load_config()
+    del config.tools.mcp_servers["browserbase"]
+    save_config(config)
+
+    consumer = asyncio.create_task(_handle_one_runtime_control())
+    result = await mcp_runtime.request_mcp_reload(loop.bus, timeout=2.0)
+    await consumer
+
+    assert result["ok"] is True
+    assert result["removed"] == ["browserbase"]
+    assert result["requires_restart"] is False
+    assert not loop.tools.has("mcp_browserbase_navigate")
+    assert closed == ["browserbase"]
+
+
+@pytest.mark.asyncio
+async def test_reload_mcp_servers_retries_configured_server_without_live_stack(
+    tmp_path,
+    monkeypatch: pytest.MonkeyPatch,
+):
+    config_path = tmp_path / "config.json"
+    monkeypatch.setattr("nanobot.config.loader._current_config_path", config_path)
+    config = load_config()
+    config.tools.mcp_servers["browserbase"] = MCPServerConfig(
+        type="stdio",
+        command="browserbase-mcp",
+    )
+    save_config(config)
+
+    async def _fake_connect(servers, registry):
+        stacks = {}
+        for name in servers:
+            registry.register(_FakeMcpTool(f"mcp_{name}_navigate"))
+            stack = AsyncExitStack()
+            await stack.__aenter__()
+            stacks[name] = stack
+        return stacks
+
+    monkeypatch.setattr("nanobot.agent.tools.mcp.connect_mcp_servers", _fake_connect)
+    loop = _make_loop(tmp_path, mcp_servers={"browserbase": config.tools.mcp_servers["browserbase"]})
+
+    result = await mcp_runtime.reload_servers(loop, loop.tools)
+
+    assert result["ok"] is True
+    assert result["added"] == []
+    assert result["changed"] == []
+    assert result["retried"] == ["browserbase"]
+    assert loop.tools.has("mcp_browserbase_navigate")
+    await loop.close_mcp()

tests/agent/test_session_manager_history.py

@@ -56,6 +56,20 @@ def test_list_sessions_includes_user_preview(tmp_path):
     assert rows[0]["preview"] == "帮我总结一下 OpenAI 的最新硬件计划"
 
 
+def test_list_sessions_bounds_preview_scan(tmp_path):
+    manager = SessionManager(tmp_path)
+    session = manager.get_or_create("websocket:chat-long-preview")
+    for index in range(220):
+        session.add_message("assistant", f"assistant trace {index}")
+    session.add_message("user", "this should not force a full sidebar scan")
+    manager.save(session)
+
+    rows = manager.list_sessions()
+
+    assert rows[0]["key"] == "websocket:chat-long-preview"
+    assert rows[0]["preview"] == "assistant trace 0"
+
+
 # --- Original regression test (from PR 2075) ---
 
 def test_get_history_drops_orphan_tool_results_when_window_cuts_tool_calls():