instrument mcp server

Author: GabrielBarberini

README.md

@@ -30,6 +30,9 @@ $ touch .env && echo MONGODB_CONNECTION_STRING="$ConnectionString" > .env
 - Dev: `python3 -m uvicorn src:app --reload --port 3000`
 - Prod: `gunicorn -k uvicorn.workers.UvicornWorker src:app -b 0.0.0.0:3000`
 
+## MCP Server
+- Infinity API automatically serves an MCP bridge at `/mcp` alongside the REST endpoints.
+
 ## Project structure
 ```
 ├── README.md    # this file

src/api.py

@@ -9,18 +9,23 @@
 from src import logger, parse_error
 from src.routes import flight, environment, motor, rocket
 from src.utils import RocketPyGZipMiddleware
+from src.mcp.server import build_mcp
 
 app = FastAPI(
+    title="Infinity API",
     swagger_ui_parameters={
         "defaultModelsExpandDepth": 0,
         "syntaxHighlight.theme": "obsidian",
-    }
+    },
 )
 app.include_router(flight.router)
 app.include_router(environment.router)
 app.include_router(motor.router)
 app.include_router(rocket.router)
 
+_mcp_server = build_mcp(app)
+app.mount('/mcp', _mcp_server.http_app())
+
 FastAPIInstrumentor.instrument_app(app)
 RequestsInstrumentor().instrument()
 

src/mcp/__init__.py

@@ -0,0 +1,20 @@
+"""FastMCP integration helpers for Infinity API."""
+
+from __future__ import annotations
+
+from fastapi import FastAPI
+from fastmcp import FastMCP
+
+
+def build_mcp(app: FastAPI) -> FastMCP:
+    """
+    Create (or return cached) FastMCP server
+    that mirrors the FastAPI app.
+    """
+
+    if hasattr(app.state, 'mcp'):
+        return app.state.mcp  # type: ignore[attr-defined]
+
+    mcp = FastMCP.from_fastapi(app, name=app.title)
+    app.state.mcp = mcp  # type: ignore[attr-defined]
+    return mcp

src/mcp/server.py

@@ -0,0 +1,29 @@
+from unittest.mock import MagicMock, patch
+
+import pytest
+
+from src.api import app
+from src.mcp.server import build_mcp
+
+
+@pytest.fixture(autouse=True)
+def reset_mcp_state():
+    if hasattr(app.state, 'mcp'):
+        delattr(app.state, 'mcp')
+    yield
+    if hasattr(app.state, 'mcp'):
+        delattr(app.state, 'mcp')
+
+
+def test_build_mcp_uses_fastapi_adapter():
+    mock_mcp = MagicMock()
+    with patch(
+        'src.mcp.server.FastMCP.from_fastapi', return_value=mock_mcp
+    ) as mock_factory:
+        result = build_mcp(app)
+        assert result is mock_mcp
+        mock_factory.assert_called_once_with(app, name=app.title)
+        # Subsequent calls reuse cached server
+        again = build_mcp(app)
+        assert again is mock_mcp
+        mock_factory.assert_called_once()