Files
nova/agents/shared/mcp_client.py

104 lines
3.3 KiB
Python

"""Multi-server MCP client using fastmcp composition.
Composes the three domain-scoped MCP servers into namespaced configurations
that agents connect to as a single client.
"""
import os
from contextlib import asynccontextmanager
from typing import Any
from fastmcp import Client
from agents.shared.parser import (
parse_prompt_result,
parse_resource_result,
parse_tool_result,
)
SERVER_MODULES = {
"shared": "mcp_servers.shared",
"ops": "mcp_servers.ops",
"passenger": "mcp_servers.passenger",
}
AGENT_PROFILES = {
"fce": ["shared", "ops", "passenger"],
"handover": ["shared", "ops"],
}
_FORWARDED_ENV_KEYS = (
"LLM_PROVIDER", "GROQ_API_KEY", "GROQ_MODEL",
"ANTHROPIC_API_KEY", "ANTHROPIC_MODEL",
"OPENAI_API_KEY", "OPENAI_BASE_URL", "OPENAI_MODEL",
"AWS_ACCESS_KEY_ID", "AWS_SECRET_ACCESS_KEY", "AWS_DEFAULT_REGION",
"BEDROCK_MODEL_ID", "USE_BEDROCK",
"PATH",
)
def _subprocess_env() -> dict:
"""Env vars forwarded to MCP server subprocesses (LLM config + active scenario)."""
from mcp_servers.data.scenarios.manager import scenario_manager
env = {k: os.environ[k] for k in _FORWARDED_ENV_KEYS if k in os.environ}
env["ACTIVE_SCENARIO"] = scenario_manager.active_id
return env
def _server_config(module: str) -> dict:
return {"command": "uv", "args": ["run", "python", "-m", module], "env": _subprocess_env()}
class MCPMultiClient:
"""Manages connections to multiple MCP servers via fastmcp Client."""
def __init__(self) -> None:
self._clients: dict[str, Client] = {}
async def connect(self, server_names: list[str]) -> None:
for name in server_names:
if name not in SERVER_MODULES:
raise ValueError(f"Unknown server: {name}. Available: {list(SERVER_MODULES.keys())}")
config = {"mcpServers": {"default": _server_config(SERVER_MODULES[name])}}
client = Client(config)
await client.__aenter__()
self._clients[name] = client
async def close(self) -> None:
for client in self._clients.values():
try:
await client.__aexit__(None, None, None)
except (Exception, BaseException):
pass
self._clients.clear()
def _client(self, server: str) -> Client:
client = self._clients.get(server)
if not client:
raise ValueError(f"Not connected to server: {server}")
return client
async def call_tool(self, server: str, tool_name: str, arguments: dict) -> Any:
result = await self._client(server).call_tool(tool_name, arguments)
return parse_tool_result(result)
async def read_resource(self, server: str, uri: str) -> Any:
result = await self._client(server).read_resource(uri)
return parse_resource_result(result)
async def get_prompt(self, server: str, prompt_name: str, arguments: dict) -> str:
result = await self._client(server).get_prompt(prompt_name, arguments)
return parse_prompt_result(result)
@asynccontextmanager
async def connect_servers(server_names: list[str]):
"""Context manager for multi-server MCP connections."""
client = MCPMultiClient()
try:
await client.connect(server_names)
yield client
finally:
await client.close()