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import asyncio
import json
from contextlib import AsyncExitStack
from dataclasses import dataclass
from pathlib import Path
from typing import Any, Literal
from mcp import ClientSession, StdioServerParameters
from mcp.client.stdio import stdio_client
from mcp.client.sse import sse_client
from mcp.client.streamable_http import streamablehttp_client
from .base import Tool, ToolResult
# Connection type aliases
ConnectionType = Literal["stdio", "sse", "http", "streamable_http"]
@dataclass
class MCPTimeoutConfig:
"""MCP timeout configuration."""
connect_timeout: float = 10.0 # Connection timeout (seconds)
execute_timeout: float = 60.0 # Tool execution timeout (seconds)
sse_read_timeout: float = 120.0 # SSE read timeout (seconds)
# Global default timeout config
_default_timeout_config = MCPTimeoutConfig()
def set_mcp_timeout_config(
connect_timeout: float | None = None,
execute_timeout: float | None = None,
sse_read_timeout: float | None = None,
) -> None:
"""Set global MCP timeout configuration.
Args:
connect_timeout: Connection timeout in seconds
execute_timeout: Tool execution timeout in seconds
sse_read_timeout: SSE read timeout in seconds
"""
global _default_timeout_config
if connect_timeout is not None:
_default_timeout_config.connect_timeout = connect_timeout
if execute_timeout is not None:
_default_timeout_config.execute_timeout = execute_timeout
if sse_read_timeout is not None:
_default_timeout_config.sse_read_timeout = sse_read_timeout
def get_mcp_timeout_config() -> MCPTimeoutConfig:
"""Get current MCP timeout configuration."""
return _default_timeout_config
class MCPTool(Tool):
"""Wrapper for MCP tools with timeout handling."""
def __init__(
self,
name: str,
description: str,
parameters: dict[str, Any],
session: ClientSession,
execute_timeout: float | None = None,
):
self._name = name
self._description = description
self._parameters = parameters
self._session = session
self._execute_timeout = execute_timeout
@property
def name(self) -> str:
return self._name
@property
def description(self) -> str:
return self._description
@property
def parameters(self) -> dict[str, Any]:
return self._parameters
async def execute(self, **kwargs) -> ToolResult:
"""Execute MCP tool via the session with timeout protection."""
timeout = self._execute_timeout or _default_timeout_config.execute_timeout
try:
# Wrap call_tool with timeout
async with asyncio.timeout(timeout):
result = await self._session.call_tool(self._name, arguments=kwargs)
# MCP tool results are a list of content items
content_parts = []
for item in result.content:
if hasattr(item, "text"):
content_parts.append(item.text)
else:
content_parts.append(str(item))
content_str = "\n".join(content_parts)
is_error = result.isError if hasattr(result, "isError") else False
return ToolResult(success=not is_error, content=content_str, error=None if not is_error else "Tool returned error")
except TimeoutError:
return ToolResult(
success=False,
content="",
error=f"MCP tool execution timed out after {timeout}s. The remote server may be slow or unresponsive.",
)
except Exception as e:
return ToolResult(success=False, content="", error=f"MCP tool execution failed: {str(e)}")
class MCPServerConnection:
"""Manages connection to a single MCP server (STDIO or URL-based) with timeout handling."""
def __init__(
self,
name: str,
connection_type: ConnectionType = "stdio",
# STDIO params
command: str | None = None,
args: list[str] | None = None,
env: dict[str, str] | None = None,
# URL-based params
url: str | None = None,
headers: dict[str, str] | None = None,
# Timeout overrides (per-server)
connect_timeout: float | None = None,
execute_timeout: float | None = None,
sse_read_timeout: float | None = None,
):
self.name = name
self.connection_type = connection_type
# STDIO
self.command = command
self.args = args or []
self.env = env or {}
# URL-based
self.url = url
self.headers = headers or {}
# Timeout settings (per-server overrides)
self.connect_timeout = connect_timeout
self.execute_timeout = execute_timeout
self.sse_read_timeout = sse_read_timeout
# Connection state
self.session: ClientSession | None = None
self.exit_stack: AsyncExitStack | None = None
self.tools: list[MCPTool] = []
def _get_connect_timeout(self) -> float:
"""Get effective connect timeout."""
return self.connect_timeout or _default_timeout_config.connect_timeout
def _get_sse_read_timeout(self) -> float:
"""Get effective SSE read timeout."""
return self.sse_read_timeout or _default_timeout_config.sse_read_timeout
def _get_execute_timeout(self) -> float:
"""Get effective execute timeout."""
return self.execute_timeout or _default_timeout_config.execute_timeout
async def connect(self) -> bool:
"""Connect to the MCP server with timeout protection."""
connect_timeout = self._get_connect_timeout()
try:
self.exit_stack = AsyncExitStack()
# Wrap connection with timeout
async with asyncio.timeout(connect_timeout):
if self.connection_type == "stdio":
read_stream, write_stream = await self._connect_stdio()
elif self.connection_type == "sse":
read_stream, write_stream = await self._connect_sse()
else: # http / streamable_http
read_stream, write_stream = await self._connect_streamable_http()
# Enter client session context
session = await self.exit_stack.enter_async_context(ClientSession(read_stream, write_stream))
self.session = session
# Initialize the session
await session.initialize()
# List available tools
tools_list = await session.list_tools()
# Wrap each tool with execute timeout
execute_timeout = self._get_execute_timeout()
for tool in tools_list.tools:
parameters = tool.inputSchema if hasattr(tool, "inputSchema") else {}
mcp_tool = MCPTool(
name=tool.name,
description=tool.description or "",
parameters=parameters,
session=session,
execute_timeout=execute_timeout,
)
self.tools.append(mcp_tool)
conn_info = self.url if self.url else self.command
print(f"✓ Connected to MCP server '{self.name}' ({self.connection_type}: {conn_info}) - loaded {len(self.tools)} tools")
for tool in self.tools:
desc = tool.description[:60] if len(tool.description) > 60 else tool.description
print(f" - {tool.name}: {desc}...")
return True
except TimeoutError:
print(f"✗ Connection to MCP server '{self.name}' timed out after {connect_timeout}s")
if self.exit_stack:
await self.exit_stack.aclose()
self.exit_stack = None
return False
except Exception as e:
print(f"✗ Failed to connect to MCP server '{self.name}': {e}")
if self.exit_stack:
await self.exit_stack.aclose()
self.exit_stack = None
import traceback
traceback.print_exc()
return False
async def _connect_stdio(self):
"""Connect via STDIO transport."""
server_params = StdioServerParameters(command=self.command, args=self.args, env=self.env if self.env else None)
return await self.exit_stack.enter_async_context(stdio_client(server_params))
async def _connect_sse(self):
"""Connect via SSE transport with timeout parameters."""
connect_timeout = self._get_connect_timeout()
sse_read_timeout = self._get_sse_read_timeout()
return await self.exit_stack.enter_async_context(
sse_client(
url=self.url,
headers=self.headers if self.headers else None,
timeout=connect_timeout,
sse_read_timeout=sse_read_timeout,
)
)
async def _connect_streamable_http(self):
"""Connect via Streamable HTTP transport with timeout parameters."""
connect_timeout = self._get_connect_timeout()
sse_read_timeout = self._get_sse_read_timeout()
# streamablehttp_client returns (read, write, get_session_id)
read_stream, write_stream, _ = await self.exit_stack.enter_async_context(
streamablehttp_client(
url=self.url,
headers=self.headers if self.headers else None,
timeout=connect_timeout,
sse_read_timeout=sse_read_timeout,
)
)
return read_stream, write_stream
async def disconnect(self):
"""Properly disconnect from the MCP server."""
if self.exit_stack:
await self.exit_stack.aclose()
self.exit_stack = None
self.session = None
# Global connections registry
_mcp_connections: list[MCPServerConnection] = []
def _determine_connection_type(server_config: dict) -> ConnectionType:
"""Determine connection type from server config."""
explicit_type = server_config.get("type", "").lower()
if explicit_type in ("stdio", "sse", "http", "streamable_http"):
return explicit_type
# Auto-detect: if url exists, default to streamable_http; otherwise stdio
if server_config.get("url"):
return "streamable_http"
return "stdio"
def _resolve_mcp_config_path(config_path: str) -> Path | None:
"""
Resolve MCP config path with fallback logic.
Priority:
1. If the specified path exists, use it
2. If mcp.json doesn't exist, try mcp-example.json in the same directory
3. Return None if no config found
Args:
config_path: User-specified config path
Returns:
Resolved Path object or None if not found
"""
config_file = Path(config_path)
# If specified path exists, use it directly
if config_file.exists():
return config_file
# Fallback: if looking for mcp.json, try mcp-example.json
if config_file.name == "mcp.json":
example_file = config_file.parent / "mcp-example.json"
if example_file.exists():
print(f"mcp.json not found, using template: {example_file}")
return example_file
return None
async def load_mcp_tools_async(config_path: str = "mcp.json") -> list[Tool]:
"""
Load MCP tools from config file.
This function:
1. Reads the MCP config file (with fallback to mcp-example.json)
2. Connects to each server (STDIO or URL-based)
3. Fetches tool definitions
4. Wraps them as Tool objects
Supported config formats:
- STDIO: {"command": "...", "args": [...], "env": {...}}
- URL-based: {"url": "https://...", "type": "sse|http|streamable_http", "headers": {...}}
Per-server timeout overrides (optional):
- "connect_timeout": float - Connection timeout in seconds
- "execute_timeout": float - Tool execution timeout in seconds
- "sse_read_timeout": float - SSE read timeout in seconds
Note:
- If mcp.json is not found, will automatically fallback to mcp-example.json
- User-specific mcp.json should be created by copying mcp-example.json
Args:
config_path: Path to MCP configuration file (default: "mcp.json")
Returns:
List of Tool objects representing MCP tools
"""
global _mcp_connections
config_file = _resolve_mcp_config_path(config_path)
if config_file is None:
print(f"MCP config not found: {config_path}")
return []
try:
with open(config_file, encoding="utf-8") as f:
config = json.load(f)
mcp_servers = config.get("mcpServers", {})
if not mcp_servers:
print("No MCP servers configured")
return []
all_tools = []
# Connect to each enabled server
for server_name, server_config in mcp_servers.items():
if server_config.get("disabled", False):
print(f"Skipping disabled server: {server_name}")
continue
conn_type = _determine_connection_type(server_config)
url = server_config.get("url")
command = server_config.get("command")
# Validate config
if conn_type == "stdio" and not command:
print(f"No command specified for STDIO server: {server_name}")
continue
if conn_type in ("sse", "http", "streamable_http") and not url:
print(f"No url specified for {conn_type.upper()} server: {server_name}")
continue
connection = MCPServerConnection(
name=server_name,
connection_type=conn_type,
command=command,
args=server_config.get("args", []),
env=server_config.get("env", {}),
url=url,
headers=server_config.get("headers", {}),
# Per-server timeout overrides from mcp.json
connect_timeout=server_config.get("connect_timeout"),
execute_timeout=server_config.get("execute_timeout"),
sse_read_timeout=server_config.get("sse_read_timeout"),
)
success = await connection.connect()
if success:
_mcp_connections.append(connection)
all_tools.extend(connection.tools)
print(f"\nTotal MCP tools loaded: {len(all_tools)}")
return all_tools
except Exception as e:
print(f"Error loading MCP config: {e}")
import traceback
traceback.print_exc()
return []
async def cleanup_mcp_connections():
"""Clean up all MCP connections."""
global _mcp_connections
for connection in _mcp_connections:
await connection.disconnect()
_mcp_connections.clear()
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