r"""Golden-case MCP stdio server — the counterpart `stdio_call_tool` is measured against.

Deliberately a NULL-ARGUMENT tool. The ingest transport carries its two coordinates in the URL
(`mcp+stdio://<server_ref>/<tool>`) and calls the tool with an empty argument dict, so a server
consumed by Door A must expose a tool that needs none. `datasource.build_mcp_server` does NOT
qualify — its `retrieve_cost_docs(query)` takes a required argument; it serves the agents'
retrieval path, not the ingest path.

The body is a fixed literal so the golden is byte-deterministic, and it carries a `|` and a `\`
to pin the §5 rule that an http-family body is rendered VERBATIM inside a fence, never escaped
into a markdown table.
"""

from mcp.server.fastmcp import FastMCP

server = FastMCP("portfolio-optimiser-golden")

_BODY = '{"service": "cost-docs", "state": "ready | partial", "path": "c:\\temp\\cache"}\n'


@server.tool()
def cost_docs() -> str:
    return _BODY


if __name__ == "__main__":
    server.run()