feat: support setting title and description for server #1799
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tests/server/test_session.py
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| async def message_handler( | ||
| message: RequestResponder[types.ServerRequest, types.ClientResult] | types.ServerNotification | Exception, | ||
| ) -> None: | ||
| if isinstance(message, Exception): # pragma: no cover |
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remove all pragmas from the test suite, instead use asserts
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Since those pragmas are already used extensively throughout this file, removing them all would significantly expand the scope of this PR. I'm happy to stick to the 'no new pragmas' rule for this change to keep the focus on the title and description support.
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Sorry yea that is what I mean, just removing the ones you added, not the existing one!
maxisbey
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improves spec compliance
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| if present). | ||
| """ | ||
|
|
||
| description: str | None = None |
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This shouldn't have a description field, only Implementation should. Check the spec schema here: https://github.com/modelcontextprotocol/modelcontextprotocol/blob/6e924e6f587f30aa810325c0985e2da0b257d4eb/schema/draft/schema.ts#L526
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This PR is based on another draft PR.
Core Type Changes
src/mcp/types.py: Addeddescription: str | Nonefield toImplementationclassServer Model Changes
src/mcp/server/models.py: Addedtitleanddescriptionfields toInitializationOptionsLow-Level Server Changes
src/mcp/server/lowlevel/server.py:Server.__init__()to accepttitleanddescriptionparameterscreate_initialization_options()to include these fieldsSession Changes
src/mcp/server/session.py: Updated to passtitleanddescriptiontoserverInfoinInitializeResultFastMCP Changes
src/mcp/server/fastmcp/server.py:titleanddescriptionparameters to__init__()@propertymethods for read accessMCPServerGithub-Issue:#1783
Motivation and Context
The MCP specification defines an
Implementationschema (used for bothclientInfoandserverInfoin initialization) that includes bothtitleanddescriptionfields for providing human-readable metadata to MCP hosts. However, the Python SDK had several gaps:Missing
descriptionfield: WhileImplementationinheritedtitlefromBaseMetadata, it was missing thedescriptionfield entirely, even though the MCP spec supports it.Server initialization limitations: The server only accepted
InitializationOptionswhich didn't support settingtitleordescription, making it impossible for servers to provide this metadata to clients.Inconsistent support: Clients could at least set
titleviaclientInfo(anImplementationobject), but servers had no way to set either field.This PR addresses the server-side implementation, allowing MCP servers to provide human-readable titles and descriptions that can be displayed by MCP hosts in their user interfaces, improving the user experience when working with multiple MCP servers.
How Has This Been Tested?
Tests
tests/server/test_session.py: Added test for low-level server title/descriptiontests/server/fastmcp/test_server.py: Added tests for FastMCP with and without title/descriptionBreaking Changes
Types of changes
Checklist
Additional context