Decorator: declare a ToolMessage class bound to a FastMCP tool.
Usage
@mcp_tool("/path/to/server.py", "get_weather")
class WeatherTool:
def pretty(self) -> str:
return f"Temp is {self.temperature}"
The server may be a string/URL/FastMCP/ClientTransport, or a zero-arg
callable returning one of those, e.g. lambda: StdioTransport(...). Using a
factory ensures a fresh transport per connection under fastmcp>=2.13.
Source code in langroid/agent/tools/mcp/decorators.py
| def mcp_tool(
server: FastMCPServerSpec, tool_name: str
) -> Callable[[Type[ToolMessage]], Type[ToolMessage]]:
"""Decorator: declare a ToolMessage class bound to a FastMCP tool.
Usage:
@mcp_tool("/path/to/server.py", "get_weather")
class WeatherTool:
def pretty(self) -> str:
return f"Temp is {self.temperature}"
The `server` may be a string/URL/FastMCP/ClientTransport, or a zero-arg
callable returning one of those, e.g. `lambda: StdioTransport(...)`. Using a
factory ensures a fresh transport per connection under fastmcp>=2.13.
"""
def decorator(user_cls: Type[ToolMessage]) -> Type[ToolMessage]:
# build the “real” ToolMessage subclass for this server/tool
RealTool: Type[ToolMessage] = get_tool(server, tool_name)
# copy user‐defined methods / attributes onto RealTool
for name, attr in user_cls.__dict__.items():
if name.startswith("__") and name.endswith("__"):
continue
setattr(RealTool, name, attr)
# preserve the user’s original name if you like:
RealTool.__name__ = user_cls.__name__
return RealTool
return decorator
|