v0.2.0-preview.2

This release replaces UseStreamableHttp with a TransportMode enum for more flexible transport configuration, with auto-detection as the new default. It also improves SSE client transport compatibility, relaxes accept header validation, and adds tool invocation error logging.

Breaking Changes

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

1. Replace UseStreamableHttp with TransportMode #456
   • SseClientTransportOptions.UseStreamableHttp property removed and replaced with TransportMode of type HttpTransportMode
   • Default behavior changed from SSE-only to auto-detect (tries Streamable HTTP first, falls back to SSE)
   • Migration: UseStreamableHttp = true → TransportMode = HttpTransportMode.StreamableHttp; default/false → TransportMode = HttpTransportMode.Sse (to preserve old behavior)

What's Changed

• Allow more accept headers #429 by @halter73
• SSE client transport: tolerate return of RPC responses in POST requests #445 by @eiriktsarpalis
• Log tool invocation errors #447 by @kooshi
• Automatically fall back from Streamable HTTP to SSE on the client by default #456 by @halter73
• Set CreateNoWindow=true in RunProcessAndWaitForExit #462 by @stephentoub

Documentation Updates

• Update README.md #437 by @Gavinluo
• Update documentation of McpJsonUtilities.DefaultOptions #463 by @eiriktsarpalis

Repository Infrastructure Updates

• Bump version to 0.2.0-preview.2 #424 by @jeffhandley
• Serilog AOT has been fixed as of 4.3.0 #434 by @agocke

Acknowledgements

• @Gavinluo made their first contribution in #437
• @kooshi made their first contribution in #447
• @AArnott submitted issues #439 (resolved by #445) and #440 (resolved by #456)
• @yinzara submitted issue #459 (resolved by #463)

Full Changelog: 0.2.0-preview.1...v0.2.0-preview.2