fastmcp/examples/tool_result_echo.py

41 lines
951 B
Python

"""
FastMCP Echo Server with Metadata
Demonstrates how to return metadata alongside content and structured data.
The meta field can include execution details, versioning, or other information
that clients may find useful.
"""
import time
from dataclasses import dataclass
from fastmcp import FastMCP
from fastmcp.tools import ToolResult
mcp = FastMCP("Echo Server")
@dataclass
class EchoData:
data: str
length: int
@mcp.tool
def echo(text: str) -> ToolResult:
"""Echo text back with metadata about the operation."""
start = time.perf_counter()
result = EchoData(data=text, length=len(text))
execution_time = (time.perf_counter() - start) * 1000
return ToolResult(
content=f"Echoed: {text}",
structured_content=result,
meta={
"execution_time_ms": round(execution_time, 2),
"character_count": len(text),
"word_count": len(text.split()),
},
)