* Option to mount SSE server to existing ASGI server
Fixes#311
Add option to mount SSE server to an existing ASGI server.
* Add a new method `sse_app` in `src/mcp/server/fastmcp/server.py` to return an instance of the SSE server app.
* Update the `run_sse_async` method in `src/mcp/server/fastmcp/server.py` to use the new `sse_app` method.
* Update the documentation in `README.md` to include instructions on how to mount the SSE server to an existing ASGI server.
* Fix the example in `README.md` to use `app.mount('/', mcp.sse_app())` instead.
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For more details, open the [Copilot Workspace session](https://copilot-workspace.githubnext.com/modelcontextprotocol/python-sdk/issues/311?shareId=XXXX-XXXX-XXXX-XXXX).
* Add `sse_app` method and update `run_sse_async` method in `server.py`
* Add `sse_app` method to return an instance of the SSE server app
* Update `run_sse_async` method to use the new `sse_app` method
Update `README.md` to include instructions for mounting SSE server
* Add section on mounting the SSE server to an existing ASGI server
* fix: Move import statements to the top of the file/
* docs: Update README to reflect changes in mounting SSE server with Starlette
* docs: Formatting of SSE server mounting example in README
* refactor: improve typing with memory stream type aliases
Move memory stream type definitions to models.py and use them throughout
the codebase for better type safety and maintainability.
GitHub-Issue:#201
* refactor: move streams to ParsedMessage
* refactor: update test files to use ParsedMessage
Updates test files to work with the ParsedMessage stream type aliases
and fixes a line length issue in test_201_client_hangs_on_logging.py.
Github-Issue:#201
* refactor: rename ParsedMessage to MessageFrame for clarity
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Co-Authored-By: Claude <noreply@anthropic.com>
* refactor: move MessageFrame class to types.py for better code organization
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Co-Authored-By: Claude <noreply@anthropic.com>
* fix pyright
* refactor: update websocket client to use MessageFrame
Modified the websocket client to work with the new MessageFrame type,
preserving raw message text and properly extracting the root JSON-RPC
message when sending.
Github-Issue:#204
* fix: use NoneType instead of None for type parameters in MessageFrame
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* refactor: rename root to message
* Close resources
* Close all resources
* Update pyproject.toml
* Close all resources
* Close all resources
* try now...
* try to ignore this
* try again
* try adding one more..
* try now
* try now
* revert ci changes
* feat: allow lowlevel servers to return a list of resources
The resource/read message in MCP allows of multiple resources
to be returned. However, in the SDK we do not allow this. This
change is such that we allow returning multiple resource in
the lowlevel API if needed. However in FastMCP we stick to
one, since a FastMCP resource defines the mime_type in the decorator
and hence a resource cannot dynamically return different mime_typed resources.
It also is just the better default to only return one resource.
However in the lowlevel API we will allow this.
Strictly speaking this is not a BC break since the new return value
is additive, but if people subclassed server, it will break them.
* feat: lower the type requriements for call_tool to Iterable
The character encoding of the stdin/stdout streams in Python is platform-
dependent. On Windows it will be something weird, like CP437 or CP1252,
depending on the locale. This change ensures that no matter the platform,
UTF-8 is used.
- Add proper generic parameter for lifespan context type
- Update README with TypedDict example for strong typing
- Fix context variable initialization in server
- Improve property return type safety
- Remove redundant documentation
- Ensure compatibility with existing tests
Adds support for the lifespan API to FastMCP server, enabling:
- Simple setup with FastMCP constructor
- Type-safe context passing to tools and handlers
- Configuration via Settings class
Adds a context manager based lifespan API in mcp.server.lowlevel.server to manage server lifecycles in a
type-safe way. This enables servers to:
- Initialize resources on startup and clean them up on shutdown
- Pass context data from startup to request handlers
- Support async startup/shutdown operations
This commit adds support for request cancellation and tracking of
in-flight requests in the MCP protocol implementation. The key
architectural changes are:
1. Request Lifecycle Management:
- Added _in_flight dictionary to BaseSession to track active requests
- Requests are tracked from receipt until completion/cancellation
- Added proper cleanup via on_complete callback
2. Cancellation Support:
- Added CancelledNotification handling in _receive_loop
- Implemented cancel() method in RequestResponder
- Uses anyio.CancelScope for robust cancellation
- Sends error response on cancellation
3. Request Context:
- Added request_ctx ContextVar for request context
- Ensures proper cleanup after request handling
- Maintains request state throughout lifecycle
4. Error Handling:
- Improved error propagation for cancelled requests
- Added proper cleanup of cancelled requests
- Maintains consistency of in-flight tracking
This change enables clients to cancel long-running requests and
servers to properly clean up resources when requests are cancelled.
Github-Issue:#88
Introduce ReadResourceContents type to properly handle MIME types in resource responses. Breaking change in FastMCP read_resource() return type.
Github-Issue:#152
The server was ignoring mime types set on resources, defaulting to text/plain
for strings and application/octet-stream for bytes. Now properly preserves
the specified mime type in both FastMCP and low-level server implementations.
Note that this is breaks backwards compatibility as it changes the return
values of read_resource() on FastMCP. It is BC compatible on lowlevel since
it only extends the callback.
Github-Issue: #152
Reported-by: eiseleMichael
This commit integrates FastMCP, a high-level MCP server implementation originally written by Jeremiah Lowin,
into the official MCP SDK. It also updates dependencies and adds new dev dependencies.
It moves the existing SDK into a .lowlevel .
We missed to have a handler for resource templates. We add this
now. One caveat is still that the `uriTemplate` in `ResourceTemplate`
is not a pydantic type.
