"""MCP server entry point for paper-doc.

Usage (from anywhere — the script anchors ``sys.path`` itself)::

    backend/.venv/bin/python backend/scripts/mcp_server.py                 # stdio
    backend/.venv/bin/python backend/scripts/mcp_server.py --check         # 自检
    backend/.venv/bin/python backend/scripts/mcp_server.py \\
        --transport http --host 0.0.0.0 --port 8931 --token secret

``stdio`` is what an MCP client spawns: Claude Code, Codex and the DeepSeek
Harness all run a command and speak JSON-RPC over its stdin/stdout. Two rules
follow from that, and both are easy to break by accident:

* **Nothing may print to stdout** except the protocol. Diagnostics go to
  stderr; a ``print`` added here for debugging would corrupt the stream and
  present as "the server disconnected".
* **The command must work from any working directory**, because a client's
  ``cwd`` is its own, not this project's. That is why the path anchor below
  exists rather than a relative ``import app``.

The CLI itself lives in :func:`app.mcp.server.main` so this file stays a
launcher: the same arguments are reachable as ``python -m app.mcp`` from
``backend/``.
"""

from __future__ import annotations

import sys
from pathlib import Path

# Running this as a plain script puts scripts/ on sys.path, not backend/, so
# `import app` would fail. Anchor to the backend directory instead.
BACKEND_DIR = Path(__file__).resolve().parents[1]
if str(BACKEND_DIR) not in sys.path:
    sys.path.insert(0, str(BACKEND_DIR))

from app.mcp.server import main  # noqa: E402

if __name__ == "__main__":
    sys.exit(main())