feat: interactive MCP tool configuration in hermes tools (#1694)

Add the ability to selectively enable/disable individual MCP server
tools through the interactive 'hermes tools' TUI.

Changes:
- tools/mcp_tool.py: Add probe_mcp_server_tools() — lightweight function
  that temporarily connects to configured MCP servers, discovers their
  tools (names + descriptions), and disconnects. No registry side effects.

- hermes_cli/tools_config.py: Add 'Configure MCP tools' option to the
  interactive menu. When selected:
  1. Probes all enabled MCP servers for their available tools
  2. Shows a per-server curses checklist with tool descriptions
  3. Pre-selects tools based on existing include/exclude config
  4. Writes changes back as tools.exclude entries in config.yaml
  5. Reports which servers failed to connect

The existing CLI commands (hermes tools enable/disable server:tool)
continue to work unchanged. This adds the interactive TUI counterpart
so users can browse and toggle MCP tools visually.

Tests: 22 new tests covering probe function edge cases and interactive
flow (pre-selection, exclude/include modes, description truncation,
multi-server handling, error paths).

tests/tools/test_mcp_probe.py

@@ -0,0 +1,210 @@
+"""Tests for probe_mcp_server_tools() in tools.mcp_tool."""
+
+import asyncio
+from types import SimpleNamespace
+from unittest.mock import AsyncMock, MagicMock, patch
+
+import pytest
+
+
+@pytest.fixture(autouse=True)
+def _reset_mcp_state():
+    """Ensure clean MCP module state before/after each test."""
+    import tools.mcp_tool as mcp
+    old_loop = mcp._mcp_loop
+    old_thread = mcp._mcp_thread
+    old_servers = dict(mcp._servers)
+    yield
+    mcp._servers.clear()
+    mcp._servers.update(old_servers)
+    mcp._mcp_loop = old_loop
+    mcp._mcp_thread = old_thread
+
+
+class TestProbeMcpServerTools:
+    """Tests for the lightweight probe_mcp_server_tools function."""
+
+    def test_returns_empty_when_mcp_not_available(self):
+        with patch("tools.mcp_tool._MCP_AVAILABLE", False):
+            from tools.mcp_tool import probe_mcp_server_tools
+            result = probe_mcp_server_tools()
+        assert result == {}
+
+    def test_returns_empty_when_no_config(self):
+        with patch("tools.mcp_tool._load_mcp_config", return_value={}):
+            from tools.mcp_tool import probe_mcp_server_tools
+            result = probe_mcp_server_tools()
+        assert result == {}
+
+    def test_returns_empty_when_all_servers_disabled(self):
+        config = {
+            "github": {"command": "npx", "enabled": False},
+            "slack": {"command": "npx", "enabled": "off"},
+        }
+        with patch("tools.mcp_tool._load_mcp_config", return_value=config):
+            from tools.mcp_tool import probe_mcp_server_tools
+            result = probe_mcp_server_tools()
+        assert result == {}
+
+    def test_returns_tools_from_successful_server(self):
+        """Successfully probed server returns its tools list."""
+        config = {
+            "github": {"command": "npx", "connect_timeout": 5},
+        }
+        mock_tool_1 = SimpleNamespace(name="create_issue", description="Create a new issue")
+        mock_tool_2 = SimpleNamespace(name="search_repos", description="Search repositories")
+
+        mock_server = MagicMock()
+        mock_server._tools = [mock_tool_1, mock_tool_2]
+        mock_server.shutdown = AsyncMock()
+
+        async def fake_connect(name, cfg):
+            return mock_server
+
+        with patch("tools.mcp_tool._load_mcp_config", return_value=config), \
+             patch("tools.mcp_tool._connect_server", side_effect=fake_connect), \
+             patch("tools.mcp_tool._ensure_mcp_loop"), \
+             patch("tools.mcp_tool._run_on_mcp_loop") as mock_run, \
+             patch("tools.mcp_tool._stop_mcp_loop"):
+
+            # Simulate running the async probe
+            def run_coro(coro, timeout=120):
+                loop = asyncio.new_event_loop()
+                try:
+                    return loop.run_until_complete(coro)
+                finally:
+                    loop.close()
+
+            mock_run.side_effect = run_coro
+
+            from tools.mcp_tool import probe_mcp_server_tools
+            result = probe_mcp_server_tools()
+
+        assert "github" in result
+        assert len(result["github"]) == 2
+        assert result["github"][0] == ("create_issue", "Create a new issue")
+        assert result["github"][1] == ("search_repos", "Search repositories")
+        mock_server.shutdown.assert_awaited_once()
+
+    def test_failed_server_omitted_from_results(self):
+        """Servers that fail to connect are silently skipped."""
+        config = {
+            "github": {"command": "npx", "connect_timeout": 5},
+            "broken": {"command": "nonexistent", "connect_timeout": 5},
+        }
+        mock_tool = SimpleNamespace(name="create_issue", description="Create")
+        mock_server = MagicMock()
+        mock_server._tools = [mock_tool]
+        mock_server.shutdown = AsyncMock()
+
+        async def fake_connect(name, cfg):
+            if name == "broken":
+                raise ConnectionError("Server not found")
+            return mock_server
+
+        with patch("tools.mcp_tool._load_mcp_config", return_value=config), \
+             patch("tools.mcp_tool._connect_server", side_effect=fake_connect), \
+             patch("tools.mcp_tool._ensure_mcp_loop"), \
+             patch("tools.mcp_tool._run_on_mcp_loop") as mock_run, \
+             patch("tools.mcp_tool._stop_mcp_loop"):
+
+            def run_coro(coro, timeout=120):
+                loop = asyncio.new_event_loop()
+                try:
+                    return loop.run_until_complete(coro)
+                finally:
+                    loop.close()
+
+            mock_run.side_effect = run_coro
+
+            from tools.mcp_tool import probe_mcp_server_tools
+            result = probe_mcp_server_tools()
+
+        assert "github" in result
+        assert "broken" not in result
+
+    def test_handles_tool_without_description(self):
+        """Tools without descriptions get empty string."""
+        config = {"github": {"command": "npx", "connect_timeout": 5}}
+        mock_tool = SimpleNamespace(name="my_tool")  # no description attribute
+
+        mock_server = MagicMock()
+        mock_server._tools = [mock_tool]
+        mock_server.shutdown = AsyncMock()
+
+        async def fake_connect(name, cfg):
+            return mock_server
+
+        with patch("tools.mcp_tool._load_mcp_config", return_value=config), \
+             patch("tools.mcp_tool._connect_server", side_effect=fake_connect), \
+             patch("tools.mcp_tool._ensure_mcp_loop"), \
+             patch("tools.mcp_tool._run_on_mcp_loop") as mock_run, \
+             patch("tools.mcp_tool._stop_mcp_loop"):
+
+            def run_coro(coro, timeout=120):
+                loop = asyncio.new_event_loop()
+                try:
+                    return loop.run_until_complete(coro)
+                finally:
+                    loop.close()
+
+            mock_run.side_effect = run_coro
+
+            from tools.mcp_tool import probe_mcp_server_tools
+            result = probe_mcp_server_tools()
+
+        assert result["github"][0] == ("my_tool", "")
+
+    def test_cleanup_called_even_on_failure(self):
+        """_stop_mcp_loop is called even when probe fails."""
+        config = {"github": {"command": "npx", "connect_timeout": 5}}
+
+        with patch("tools.mcp_tool._load_mcp_config", return_value=config), \
+             patch("tools.mcp_tool._ensure_mcp_loop"), \
+             patch("tools.mcp_tool._run_on_mcp_loop", side_effect=RuntimeError("boom")), \
+             patch("tools.mcp_tool._stop_mcp_loop") as mock_stop:
+
+            from tools.mcp_tool import probe_mcp_server_tools
+            result = probe_mcp_server_tools()
+
+        assert result == {}
+        mock_stop.assert_called_once()
+
+    def test_skips_disabled_servers(self):
+        """Disabled servers are not probed."""
+        config = {
+            "github": {"command": "npx", "connect_timeout": 5},
+            "disabled_one": {"command": "npx", "enabled": False},
+        }
+        mock_tool = SimpleNamespace(name="create_issue", description="Create")
+        mock_server = MagicMock()
+        mock_server._tools = [mock_tool]
+        mock_server.shutdown = AsyncMock()
+
+        connect_calls = []
+
+        async def fake_connect(name, cfg):
+            connect_calls.append(name)
+            return mock_server
+
+        with patch("tools.mcp_tool._load_mcp_config", return_value=config), \
+             patch("tools.mcp_tool._connect_server", side_effect=fake_connect), \
+             patch("tools.mcp_tool._ensure_mcp_loop"), \
+             patch("tools.mcp_tool._run_on_mcp_loop") as mock_run, \
+             patch("tools.mcp_tool._stop_mcp_loop"):
+
+            def run_coro(coro, timeout=120):
+                loop = asyncio.new_event_loop()
+                try:
+                    return loop.run_until_complete(coro)
+                finally:
+                    loop.close()
+
+            mock_run.side_effect = run_coro
+
+            from tools.mcp_tool import probe_mcp_server_tools
+            result = probe_mcp_server_tools()
+
+        assert "github" in result
+        assert "disabled_one" not in result
+        assert "disabled_one" not in connect_calls