# mypy: disable-error-code=unused-ignore from __future__ import annotations import json from abc import ABC, abstractmethod from contextlib import AbstractAsyncContextManager, AsyncExitStack from datetime import timedelta from pathlib import Path from typing import Any, Literal from urllib.parse import urlparse from anyio.streams.memory import MemoryObjectReceiveStream, MemoryObjectSendStream try: from mcp import ClientSession, stdio_client from mcp.client.sse import sse_client from mcp.client.stdio import StdioServerParameters from mcp.client.streamable_http import GetSessionIdCallback, streamablehttp_client from mcp.shared.message import SessionMessage except ImportError as e: raise ImportError( "The 'mcp' package is required to run the MCP server integration but is not installed.\n" "To fix this, install the optional dependency: pip install 'livekit-agents[mcp]'" ) from e from .tool_context import ( RawFunctionTool, ToolError, function_tool, get_function_info, get_raw_function_info, is_function_tool, is_raw_function_tool, ) MCPTool = RawFunctionTool class MCPServer(ABC): def __init__(self, *, client_session_timeout_seconds: float) -> None: self._client: ClientSession | None = None self._exit_stack: AsyncExitStack = AsyncExitStack() self._read_timeout = client_session_timeout_seconds self._cache_dirty = True self._lk_tools: list[MCPTool] | None = None @property def initialized(self) -> bool: return self._client is not None def invalidate_cache(self) -> None: self._cache_dirty = True async def initialize(self) -> None: try: streams = await self._exit_stack.enter_async_context(self.client_streams()) receive_stream, send_stream = streams[0], streams[1] self._client = await self._exit_stack.enter_async_context( ClientSession( receive_stream, send_stream, read_timeout_seconds=timedelta(seconds=self._read_timeout) if self._read_timeout else None, ) ) await self._client.initialize() # type: ignore[union-attr] self._initialized = True except Exception: await self.aclose() raise async def list_tools(self) -> list[MCPTool]: if self._client is None: raise RuntimeError("MCPServer isn't initialized") if not self._cache_dirty and self._lk_tools is not None: return self._lk_tools tools = await self._client.list_tools() lk_tools = [ self._make_function_tool(tool.name, tool.description, tool.inputSchema, tool.meta) for tool in tools.tools ] self._lk_tools = lk_tools self._cache_dirty = False return lk_tools def _make_function_tool( self, name: str, description: str | None, input_schema: dict[str, Any], meta: dict[str, Any] | None, ) -> MCPTool: async def _tool_called(raw_arguments: dict[str, Any]) -> Any: # In case (somehow), the tool is called after the MCPServer aclose. if self._client is None: raise ToolError( "Tool invocation failed: internal service is unavailable. " "Please check that the MCPServer is still running." ) tool_result = await self._client.call_tool(name, raw_arguments) if tool_result.isError: error_str = "\n".join( part.text if hasattr(part, "text") else str(part) for part in tool_result.content ) raise ToolError(error_str) # TODO(theomonnom): handle images & binary messages if len(tool_result.content) == 1: return tool_result.content[0].model_dump_json() elif len(tool_result.content) > 1: return json.dumps([item.model_dump() for item in tool_result.content]) raise ToolError( f"Tool '{name}' completed without producing a result. " "This might indicate an issue with internal processing." ) raw_schema = { "name": name, "description": description, "parameters": input_schema, } if meta: raw_schema["meta"] = meta return function_tool(_tool_called, raw_schema=raw_schema) async def aclose(self) -> None: try: await self._exit_stack.aclose() finally: self._client = None self._lk_tools = None @abstractmethod def client_streams( self, ) -> AbstractAsyncContextManager[ tuple[ MemoryObjectReceiveStream[SessionMessage | Exception], MemoryObjectSendStream[SessionMessage], ] | tuple[ MemoryObjectReceiveStream[SessionMessage | Exception], MemoryObjectSendStream[SessionMessage], GetSessionIdCallback, ] ]: ... class MCPServerHTTP(MCPServer): """ HTTP-based MCP server with configurable transport type and tool filtering. Args: url: The URL of the MCP server transport_type: Explicit transport type - "sse" or "streamable_http". If None, transport type is auto-detected from URL path: - URLs ending with 'sse' use Server-Sent Events (SSE) transport - URLs ending with 'mcp' use streamable HTTP transport - For other URLs, defaults to SSE transport for backward compatibility allowed_tools: Optional list of tool names to filter. If provided, only tools whose names are in this list will be available. If None, all tools from the server will be available. headers: Optional HTTP headers to include in requests timeout: Connection timeout in seconds (default: 5) sse_read_timeout: SSE read timeout in seconds (default: 300) client_session_timeout_seconds: Client session timeout in seconds (default: 5) Note: SSE transport is being deprecated in favor of streamable HTTP transport. See: https://github.com/modelcontextprotocol/modelcontextprotocol/pull/206 """ def __init__( self, url: str, transport_type: Literal["sse", "streamable_http"] | None = None, allowed_tools: list[str] | None = None, headers: dict[str, Any] | None = None, timeout: float = 5, sse_read_timeout: float = 60 * 5, client_session_timeout_seconds: float = 5, ) -> None: super().__init__(client_session_timeout_seconds=client_session_timeout_seconds) self.url = url self.headers = headers self._timeout = timeout self._sse_read_timeout = sse_read_timeout self._allowed_tools = set(allowed_tools) if allowed_tools else None # Determine transport type: explicit > URL-based detection if transport_type is not None: if transport_type not in ("sse", "streamable_http"): raise ValueError( f"transport_type must be 'sse' or 'streamable_http', got '{transport_type}'" ) self._use_streamable_http = transport_type == "streamable_http" else: # Fall back to URL-based detection for backward compatibility self._use_streamable_http = self._should_use_streamable_http(url) def _should_use_streamable_http(self, url: str) -> bool: """ Determine transport type based on URL path (for backward compatibility). Returns True for streamable HTTP if URL ends with 'mcp', False for SSE if URL ends with 'sse' or for backward compatibility. """ parsed_url = urlparse(url) path_lower = parsed_url.path.lower().rstrip("/") return path_lower.endswith("/mcp") def client_streams( self, ) -> AbstractAsyncContextManager[ tuple[ MemoryObjectReceiveStream[SessionMessage | Exception], MemoryObjectSendStream[SessionMessage], ] | tuple[ MemoryObjectReceiveStream[SessionMessage | Exception], MemoryObjectSendStream[SessionMessage], GetSessionIdCallback, ] ]: if self._use_streamable_http: return streamablehttp_client( # type: ignore[no-any-return] url=self.url, headers=self.headers, timeout=timedelta(seconds=self._timeout), sse_read_timeout=timedelta(seconds=self._sse_read_timeout), ) else: return sse_client( # type: ignore[no-any-return] url=self.url, headers=self.headers, timeout=self._timeout, sse_read_timeout=self._sse_read_timeout, ) async def list_tools(self) -> list[MCPTool]: """ List tools from the MCP server, filtered by allowed_tools if specified. """ all_tools = await super().list_tools() # If no filter is set, return all tools if self._allowed_tools is None: return all_tools # Filter tools by name return self._filter_tools(all_tools) def _filter_tools(self, tools: list[MCPTool]) -> list[MCPTool]: """ Filter tools by allowed_tools if specified. """ if self._allowed_tools is None: return tools filtered_tools: list[MCPTool] = [] for tool in tools: # Get tool name based on tool type if is_function_tool(tool): tool_name = get_function_info(tool).name elif is_raw_function_tool(tool): tool_name = get_raw_function_info(tool).name else: # Fallback: skip tools we can't identify continue if tool_name in self._allowed_tools: filtered_tools.append(tool) # type: ignore[arg-type] return filtered_tools def __repr__(self) -> str: transport_type = "streamable_http" if self._use_streamable_http else "sse" allowed_str = f", allowed_tools={list(self._allowed_tools)}" if self._allowed_tools else "" return f"MCPServerHTTP(url={self.url}, transport={transport_type}{allowed_str})" class MCPServerStdio(MCPServer): def __init__( self, command: str, args: list[str], env: dict[str, str] | None = None, cwd: str | Path | None = None, client_session_timeout_seconds: float = 5, ) -> None: super().__init__(client_session_timeout_seconds=client_session_timeout_seconds) self.command = command self.args = args self.env = env self.cwd = cwd def client_streams( self, ) -> AbstractAsyncContextManager[ tuple[ MemoryObjectReceiveStream[SessionMessage | Exception], MemoryObjectSendStream[SessionMessage], ] ]: return stdio_client( # type: ignore[no-any-return] StdioServerParameters(command=self.command, args=self.args, env=self.env, cwd=self.cwd) ) def __repr__(self) -> str: return f"MCPServerStdio(command={self.command}, args={self.args}, cwd={self.cwd})"