yi
249 lines
9.9 KiB
Python
249 lines
9.9 KiB
Python
"""MCP client: connects to MCP servers and wraps their tools as native nanobot tools."""
|
|
|
|
import asyncio
|
|
from contextlib import AsyncExitStack
|
|
from typing import Any
|
|
|
|
import httpx
|
|
from loguru import logger
|
|
|
|
from nanobot.agent.tools.base import Tool
|
|
from nanobot.agent.tools.registry import ToolRegistry
|
|
|
|
|
|
def _extract_nullable_branch(options: Any) -> tuple[dict[str, Any], bool] | None:
|
|
"""Return the single non-null branch for nullable unions."""
|
|
if not isinstance(options, list):
|
|
return None
|
|
|
|
non_null: list[dict[str, Any]] = []
|
|
saw_null = False
|
|
for option in options:
|
|
if not isinstance(option, dict):
|
|
return None
|
|
if option.get("type") == "null":
|
|
saw_null = True
|
|
continue
|
|
non_null.append(option)
|
|
|
|
if saw_null and len(non_null) == 1:
|
|
return non_null[0], True
|
|
return None
|
|
|
|
|
|
def _normalize_schema_for_openai(schema: Any) -> dict[str, Any]:
|
|
"""Normalize only nullable JSON Schema patterns for tool definitions."""
|
|
if not isinstance(schema, dict):
|
|
return {"type": "object", "properties": {}}
|
|
|
|
normalized = dict(schema)
|
|
|
|
raw_type = normalized.get("type")
|
|
if isinstance(raw_type, list):
|
|
non_null = [item for item in raw_type if item != "null"]
|
|
if "null" in raw_type and len(non_null) == 1:
|
|
normalized["type"] = non_null[0]
|
|
normalized["nullable"] = True
|
|
|
|
for key in ("oneOf", "anyOf"):
|
|
nullable_branch = _extract_nullable_branch(normalized.get(key))
|
|
if nullable_branch is not None:
|
|
branch, _ = nullable_branch
|
|
merged = {k: v for k, v in normalized.items() if k != key}
|
|
merged.update(branch)
|
|
normalized = merged
|
|
normalized["nullable"] = True
|
|
break
|
|
|
|
if "properties" in normalized and isinstance(normalized["properties"], dict):
|
|
normalized["properties"] = {
|
|
name: _normalize_schema_for_openai(prop)
|
|
if isinstance(prop, dict)
|
|
else prop
|
|
for name, prop in normalized["properties"].items()
|
|
}
|
|
|
|
if "items" in normalized and isinstance(normalized["items"], dict):
|
|
normalized["items"] = _normalize_schema_for_openai(normalized["items"])
|
|
|
|
if normalized.get("type") != "object":
|
|
return normalized
|
|
|
|
normalized.setdefault("properties", {})
|
|
normalized.setdefault("required", [])
|
|
return normalized
|
|
|
|
|
|
class MCPToolWrapper(Tool):
|
|
"""Wraps a single MCP server tool as a nanobot Tool."""
|
|
|
|
def __init__(self, session, server_name: str, tool_def, tool_timeout: int = 30):
|
|
self._session = session
|
|
self._original_name = tool_def.name
|
|
self._name = f"mcp_{server_name}_{tool_def.name}"
|
|
self._description = tool_def.description or tool_def.name
|
|
raw_schema = tool_def.inputSchema or {"type": "object", "properties": {}}
|
|
self._parameters = _normalize_schema_for_openai(raw_schema)
|
|
self._tool_timeout = tool_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: Any) -> str:
|
|
from mcp import types
|
|
|
|
try:
|
|
result = await asyncio.wait_for(
|
|
self._session.call_tool(self._original_name, arguments=kwargs),
|
|
timeout=self._tool_timeout,
|
|
)
|
|
except asyncio.TimeoutError:
|
|
logger.warning("MCP tool '{}' timed out after {}s", self._name, self._tool_timeout)
|
|
return f"(MCP tool call timed out after {self._tool_timeout}s)"
|
|
except asyncio.CancelledError:
|
|
# MCP SDK's anyio cancel scopes can leak CancelledError on timeout/failure.
|
|
# Re-raise only if our task was externally cancelled (e.g. /stop).
|
|
task = asyncio.current_task()
|
|
if task is not None and task.cancelling() > 0:
|
|
raise
|
|
logger.warning("MCP tool '{}' was cancelled by server/SDK", self._name)
|
|
return "(MCP tool call was cancelled)"
|
|
except Exception as exc:
|
|
logger.exception(
|
|
"MCP tool '{}' failed: {}: {}",
|
|
self._name,
|
|
type(exc).__name__,
|
|
exc,
|
|
)
|
|
return f"(MCP tool call failed: {type(exc).__name__})"
|
|
|
|
parts = []
|
|
for block in result.content:
|
|
if isinstance(block, types.TextContent):
|
|
parts.append(block.text)
|
|
else:
|
|
parts.append(str(block))
|
|
return "\n".join(parts) or "(no output)"
|
|
|
|
|
|
async def connect_mcp_servers(
|
|
mcp_servers: dict, registry: ToolRegistry, stack: AsyncExitStack
|
|
) -> None:
|
|
"""Connect to configured MCP servers and register their tools."""
|
|
from mcp import ClientSession, StdioServerParameters
|
|
from mcp.client.sse import sse_client
|
|
from mcp.client.stdio import stdio_client
|
|
from mcp.client.streamable_http import streamable_http_client
|
|
|
|
for name, cfg in mcp_servers.items():
|
|
try:
|
|
transport_type = cfg.type
|
|
if not transport_type:
|
|
if cfg.command:
|
|
transport_type = "stdio"
|
|
elif cfg.url:
|
|
# Convention: URLs ending with /sse use SSE transport; others use streamableHttp
|
|
transport_type = (
|
|
"sse" if cfg.url.rstrip("/").endswith("/sse") else "streamableHttp"
|
|
)
|
|
else:
|
|
logger.warning("MCP server '{}': no command or url configured, skipping", name)
|
|
continue
|
|
|
|
if transport_type == "stdio":
|
|
params = StdioServerParameters(
|
|
command=cfg.command, args=cfg.args, env=cfg.env or None
|
|
)
|
|
read, write = await stack.enter_async_context(stdio_client(params))
|
|
elif transport_type == "sse":
|
|
def httpx_client_factory(
|
|
headers: dict[str, str] | None = None,
|
|
timeout: httpx.Timeout | None = None,
|
|
auth: httpx.Auth | None = None,
|
|
) -> httpx.AsyncClient:
|
|
merged_headers = {**(cfg.headers or {}), **(headers or {})}
|
|
return httpx.AsyncClient(
|
|
headers=merged_headers or None,
|
|
follow_redirects=True,
|
|
timeout=timeout,
|
|
auth=auth,
|
|
)
|
|
|
|
read, write = await stack.enter_async_context(
|
|
sse_client(cfg.url, httpx_client_factory=httpx_client_factory)
|
|
)
|
|
elif transport_type == "streamableHttp":
|
|
# Always provide an explicit httpx client so MCP HTTP transport does not
|
|
# inherit httpx's default 5s timeout and preempt the higher-level tool timeout.
|
|
http_client = await stack.enter_async_context(
|
|
httpx.AsyncClient(
|
|
headers=cfg.headers or None,
|
|
follow_redirects=True,
|
|
timeout=None,
|
|
)
|
|
)
|
|
read, write, _ = await stack.enter_async_context(
|
|
streamable_http_client(cfg.url, http_client=http_client)
|
|
)
|
|
else:
|
|
logger.warning("MCP server '{}': unknown transport type '{}'", name, transport_type)
|
|
continue
|
|
|
|
session = await stack.enter_async_context(ClientSession(read, write))
|
|
await session.initialize()
|
|
|
|
tools = await session.list_tools()
|
|
enabled_tools = set(cfg.enabled_tools)
|
|
allow_all_tools = "*" in enabled_tools
|
|
registered_count = 0
|
|
matched_enabled_tools: set[str] = set()
|
|
available_raw_names = [tool_def.name for tool_def in tools.tools]
|
|
available_wrapped_names = [f"mcp_{name}_{tool_def.name}" for tool_def in tools.tools]
|
|
for tool_def in tools.tools:
|
|
wrapped_name = f"mcp_{name}_{tool_def.name}"
|
|
if (
|
|
not allow_all_tools
|
|
and tool_def.name not in enabled_tools
|
|
and wrapped_name not in enabled_tools
|
|
):
|
|
logger.debug(
|
|
"MCP: skipping tool '{}' from server '{}' (not in enabledTools)",
|
|
wrapped_name,
|
|
name,
|
|
)
|
|
continue
|
|
wrapper = MCPToolWrapper(session, name, tool_def, tool_timeout=cfg.tool_timeout)
|
|
registry.register(wrapper)
|
|
logger.debug("MCP: registered tool '{}' from server '{}'", wrapper.name, name)
|
|
registered_count += 1
|
|
if enabled_tools:
|
|
if tool_def.name in enabled_tools:
|
|
matched_enabled_tools.add(tool_def.name)
|
|
if wrapped_name in enabled_tools:
|
|
matched_enabled_tools.add(wrapped_name)
|
|
|
|
if enabled_tools and not allow_all_tools:
|
|
unmatched_enabled_tools = sorted(enabled_tools - matched_enabled_tools)
|
|
if unmatched_enabled_tools:
|
|
logger.warning(
|
|
"MCP server '{}': enabledTools entries not found: {}. Available raw names: {}. "
|
|
"Available wrapped names: {}",
|
|
name,
|
|
", ".join(unmatched_enabled_tools),
|
|
", ".join(available_raw_names) or "(none)",
|
|
", ".join(available_wrapped_names) or "(none)",
|
|
)
|
|
|
|
logger.info("MCP server '{}': connected, {} tools registered", name, registered_count)
|
|
except Exception as e:
|
|
logger.error("MCP server '{}': failed to connect: {}", name, e)
|