📝 Add docstrings to mcp_server

Docstrings generation was requested by @GabrielBarberini.

* #61 (comment)

The following files were modified:

* `src/mcp/server.py`
* `src/repositories/interface.py`
* `tests/unit/test_mcp/test_mcp_server.py`

Author: coderabbitai[bot]

src/mcp/server.py

@@ -8,13 +8,18 @@
 
 def build_mcp(app: FastAPI) -> FastMCP:
     """
-    Create (or return cached) FastMCP server
-    that mirrors the FastAPI app.
+    Create or return a cached FastMCP server that mirrors the given FastAPI app.
+    
+    Parameters:
+        app (FastAPI): FastAPI application to mirror; the created FastMCP instance is cached on `app.state.mcp`.
+    
+    Returns:
+        FastMCP: The FastMCP instance corresponding to the provided 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
+    return mcp

src/repositories/interface.py

@@ -35,6 +35,19 @@ def __init__(self):
 
 
 def repository_exception_handler(method):
+    """
+    Decorator that standardizes error handling and logging for repository coroutine methods.
+    
+    Parameters:
+        method (Callable): The asynchronous repository method to wrap.
+    
+    Returns:
+        wrapper (Callable): An async wrapper that:
+            - re-raises PyMongoError after logging the exception,
+            - re-raises RepositoryNotInitializedException after logging the exception,
+            - logs any other exception and raises an HTTPException with status 500 and detail 'Unexpected error ocurred',
+            - always logs completion of the repository method call with the repository name, method name, and kwargs.
+    """
     @functools.wraps(method)
     async def wrapper(self, *args, **kwargs):
         try:
@@ -81,13 +94,31 @@ class RepositoryInterface:
     _global_thread_lock = threading.Lock()
 
     def __new__(cls, *args, **kwargs):
+        """
+        Ensure a single thread-safe instance exists for the subclass.
+        
+        Creates and returns the singleton instance for this subclass, creating it if absent while holding a global thread lock to prevent concurrent instantiation.
+        
+        Returns:
+            The singleton instance of the subclass.
+        """
         with cls._global_thread_lock:
             if cls not in cls._global_instances:
                 instance = super().__new__(cls)
                 cls._global_instances[cls] = instance
         return cls._global_instances[cls]
 
     def __init__(self, model: ApiBaseModel, *, max_pool_size: int = 3):
+        """
+        Initialize the repository instance for a specific API model and configure its connection pool.
+        
+        Parameters:
+            model (ApiBaseModel): The API model used for validation and to determine the repository's collection.
+            max_pool_size (int, optional): Maximum size of the MongoDB connection pool. Defaults to 3.
+        
+        Notes:
+            If the instance is already initialized, this constructor will not reconfigure it. Initialization of the underlying connection is started asynchronously.
+        """
         if not getattr(self, '_initialized', False):
             self.model = model
             self._max_pool_size = max_pool_size
@@ -96,6 +127,11 @@ def __init__(self, model: ApiBaseModel, *, max_pool_size: int = 3):
 
     @retry(stop=stop_after_attempt(5), wait=wait_fixed(0.2))
     async def _async_init(self):
+        """
+        Perform idempotent, retry-safe asynchronous initialization of the repository instance.
+        
+        Ensures a per-instance asyncio.Lock exists and acquires it to run initialization exactly once; on success it marks the instance as initialized and sets the internal _initialized_event so awaiters can proceed. If initialization fails, the original exception from _initialize_connection is propagated after logging.
+        """
         if getattr(self, '_initialized', False):
             return
 
@@ -117,6 +153,11 @@ async def _async_init(self):
             self._initialized_event.set()
 
     def _initialize(self):
+        """
+        Ensure the repository's asynchronous initializer is executed: run it immediately if no event loop is active, otherwise schedule it on the running loop.
+        
+        If there is no running asyncio event loop, this method runs self._async_init() to completion on the current thread, blocking until it finishes. If an event loop is running, it schedules self._async_init() as a background task on that loop and returns immediately.
+        """
         try:
             loop = asyncio.get_running_loop()
         except RuntimeError:
@@ -125,13 +166,27 @@ def _initialize(self):
             loop.create_task(self._async_init())
 
     async def __aenter__(self):
+        """
+        Waits for repository initialization to complete and returns the repository instance.
+        
+        Returns:
+            RepositoryInterface: The initialized repository instance.
+        """
         await self._initialized_event.wait()  # Ensure initialization is complete
         return self
 
     async def __aexit__(self, exc_type, exc_value, traceback):
         await self._initialized_event.wait()
 
     def _initialize_connection(self):
+        """
+        Initialize the MongoDB async client, store the connection string, and bind the collection for this repository instance.
+        
+        This method fetches the MongoDB connection string from secrets, creates an AsyncMongoClient configured with pool and timeout settings, and sets self._collection to the repository's collection named by the model. On success it logs the initialized client; on failure it raises a ConnectionError.
+        
+        Raises:
+            ConnectionError: If the client or collection cannot be initialized.
+        """
         try:
             self._connection_string = Secrets.get_secret(
                 "MONGODB_CONNECTION_STRING"
@@ -229,4 +284,4 @@ async def find_by_query(self, query: dict):
             parsed_model = self.model.model_validate(read_data)
             parsed_model.set_id(str(read_data["_id"]))
             parsed_models.append(parsed_model)
-        return parsed_models
+        return parsed_models

tests/unit/test_mcp/test_mcp_server.py

@@ -14,6 +14,11 @@
 
 @pytest.fixture(autouse=True)
 def reset_mcp_state():
+    """
+    Ensure the FastAPI app has no lingering MCP state before and after a test.
+    
+    This fixture deletes app.state.mcp if it exists, yields control to the test, and then deletes app.state.mcp again to guarantee the MCP state is cleared between tests.
+    """
     if hasattr(app.state, 'mcp'):
         delattr(app.state, 'mcp')
     yield
@@ -63,4 +68,4 @@ async def test_mcp_tools_cover_registered_routes():
         # Path parameters must be represented as required MCP tool arguments
         assert path_params.issubset(
             required
-        ), f"{tool_name} missing path params {path_params - required}"
+        ), f"{tool_name} missing path params {path_params - required}"