Files
modelcontextprotocol--pytho…/tests/interaction/transports/_stdio_server.py
2026-08-18 10:50:47 +02:00

72 lines
2.5 KiB
Python

"""Low-level stdio server for the interaction suite's subprocess test."""
import sys
import warnings
import anyio
import coverage
from mcp_types import (
CallToolRequestParams,
CallToolResult,
EmptyResult,
ListToolsResult,
PaginatedRequestParams,
SetLevelRequestParams,
TextContent,
Tool,
)
from mcp.server import Server, ServerRequestContext
from mcp.server.stdio import stdio_server
from mcp.shared.exceptions import MCPDeprecationWarning
async def list_tools(ctx: ServerRequestContext, params: PaginatedRequestParams | None) -> ListToolsResult:
return ListToolsResult(
tools=[
Tool(
name="echo",
input_schema={"type": "object", "properties": {"text": {"type": "string"}}, "required": ["text"]},
)
]
)
async def call_tool(ctx: ServerRequestContext, params: CallToolRequestParams) -> CallToolResult:
assert params.name == "echo"
assert params.arguments is not None
text = params.arguments["text"]
with warnings.catch_warnings():
warnings.simplefilter("ignore", MCPDeprecationWarning)
await ctx.session.send_log_message(level="info", data=f"echoing {text}", logger="echo") # pyright: ignore[reportDeprecated]
return CallToolResult(content=[TextContent(text=text)])
async def set_logging_level(ctx: ServerRequestContext, params: SetLevelRequestParams) -> EmptyResult:
"""Registered so the logging capability is advertised; the client never sets a level."""
raise NotImplementedError
with warnings.catch_warnings():
warnings.simplefilter("ignore", MCPDeprecationWarning)
server = Server( # pyright: ignore[reportDeprecated]
"stdio-echo", on_list_tools=list_tools, on_call_tool=call_tool, on_set_logging_level=set_logging_level
)
async def main() -> None:
async with stdio_server() as (read_stream, write_stream):
await server.run(read_stream, write_stream, server.create_initialization_options())
# Save subprocess coverage before the marker so forced teardown cannot lose it.
cov = getattr(coverage.process_startup, "coverage", None)
if cov is not None: # pragma: no branch
# Leave nothing for coverage's atexit hook to rewrite if teardown is interrupted.
cov.stop()
cov.save() # pragma: lax no cover - untraced: stop() above already ended measurement
# The test uses this marker to distinguish clean exit from termination.
print("stdio-echo: clean exit", file=sys.stderr, flush=True) # pragma: lax no cover
if __name__ == "__main__":
anyio.run(main)