v0.1.0-preview.9

This release wraps each MCP request in a dependency injection service scope, introduces the Streamable HTTP transport with StreamableHttpHandler and WithHttpTransport, updates OpenTelemetry instrumentation with context propagation, and cleans up logging. It includes several breaking changes to handler delegate signatures, HTTP transport configuration, and transport base class APIs.

Breaking Changes

Refer to the C# SDK Versioning documentation for details on versioning and breaking change policies.

1. Wrap each request in a service scope #276

   • All capability handler delegate types changed from Func<..., Task<T>> to Func<..., ValueTask<T>> including SamplingHandler, ListToolsHandler, CallToolHandler, ListPromptsHandler, GetPromptHandler, and all resource/completion/logging handlers
   • McpServerTool.InvokeAsync and McpServerPrompt.GetAsync return types changed to ValueTask

2. Add StreamableHttpHandler and WithHttpTransport #291

   • MapMcp removed configureOptionsAsync and runSessionAsync parameters; configuration moved to WithHttpTransport(Action<HttpServerTransportOptions>?)
   • SseClientTransportOptions.MaxReconnectAttempts and ReconnectDelay properties removed

3. Clean up logging #286

   • TransportBase constructor changed from (ILoggerFactory?) to (string name, ILoggerFactory?) — required parameter added
   • TransportBase.EndpointName renamed to TransportBase.Name
   • TransportBase.Logger accessibility narrowed from protected to private protected
   • Custom transport implementations extending TransportBase must update

What's Changed

• Wrap each request in a service scope #276 by @stephentoub
• OpenTelemetry: context propagation and semconv update #262 by @lmolkova
• Add AdditionalHeader handling to ReceiveMessageAsync #295 by @ClosetheWorld
• Add StreamableHttpHandler and WithHttpTransport #291 by @halter73
• Remove unnecessary $ and fix some typos #305 by @MikeAlhayek
• Clean up logging #286 by @stephentoub

Documentation Updates

• Fix the docs and make them more readable #281 by @MikeAlhayek

Repository Infrastructure Updates

• Bump version to 0.1.0-preview.9 #284 by @eiriktsarpalis
• Workflow refactoring and improvements #273 by @jeffhandley

Acknowledgements

• @MikeAlhayek made their first contribution in #281
• @lmolkova made their first contribution in #262
• @ClosetheWorld made their first contribution in #295
• @JeffreySu submitted issue #234 (resolved by #276)
• @gong626035906 submitted issue #198 (resolved by #276)

Full Changelog: v0.1.0-preview.8...v0.1.0-preview.9