v0.6.0-preview.1

This release includes improvements to source generator robustness, JSON-RPC deserialization performance, and OpenTelemetry semantic convention alignment. It also adds OAuth incremental scope consent support, fixes session timeout issues, and corrects tool result message handling for sampling with tools. Several documentation improvements and new client conformance tests round out the release.

What's Changed

• Remove s_additionalProperties from McpClientTool #1080 by @stephentoub (co-authored by @Copilot)
• Migrate from Anthropic.SDK to official Anthropic package #1083 by @stephentoub (co-authored by @Copilot)
• Improve caching in XmlToDescriptionGenerator #1010 by @stephentoub
• Support incremental scope consent (SEP-835) #1084 by @halter73
• Resource subscribe should be true if handler provided #676 by @PederHP (co-authored by @halter73 @mikekistler)
• Add request duration to LogRequestHandlerCompleted and LogRequestHandlerException log messages #1092 by @stephentoub (co-authored by @Copilot)
• Fix session timeout due to timestamp frequency mismatch and activity tracking #1106 by @stephentoub (co-authored by @Copilot @eiriktsarpalis)
• Add CS1066 suppressor for MCP server methods with optional parameters #1110 by @stephentoub (co-authored by @Copilot)
• Fix CreateSamplingHandler to use ChatRole.Tool for tool result messages #1128 by @stephentoub (co-authored by @Copilot @MackinnonBuck)
• Add examples of icons on tools, resources, prompts, and server implementation to EverythingServer #1096 by @mikekistler (co-authored by @halter73)
• Use fully-qualified type names in generated partial method signatures #1135 by @stephentoub (co-authored by @Copilot)
• Optimize JsonRpcMessage deserialization with single-pass parsing #1138 by @eiriktsarpalis (co-authored by @Copilot @Scooletz @stephentoub)
• Align telemetry with OpenTelemetry MCP semantic conventions #1139 by @stephentoub (co-authored by @Copilot)

Documentation Updates

• Fix Icon.Theme documentation to match MCP specification #1090 by @stephentoub (co-authored by @Copilot)
• Document HttpRequestException thrown by McpClient.CreateAsync #1095 by @stephentoub (co-authored by @Copilot)
• Add missing exception documentation to public API surface #1103 by @stephentoub (co-authored by @Copilot)
• Improve docs landing page #1114 by @gewarren
• Add CONTRIBUTING.md #1125 by @mikekistler

Test Improvements

• Remove private reflection from tests #1107 by @stephentoub (co-authored by @Copilot @halter73)
• Add client conformance tests #1102 by @mikekistler (co-authored by @halter73)

Repository Infrastructure Updates

• Bump actions/setup-node from 6.0.0 to 6.1.0 #1074
• Bump danielpalme/ReportGenerator-GitHub-Action from 5.5.0 to 5.5.1 #1073
• Bump actions/checkout from 5.0.1 to 6.0.0 #1005
• Bump version to 0.5.0-preview.2. Update NuGet Project URL. #1078 by @jeffhandley
• Update Microsoft.Extensions.AI dependencies to 10.1.0 #1082 by @stephentoub (co-authored by @Copilot)
• Update Microsoft.Extensions.AI* packages to latest versions #1093 by @stephentoub (co-authored by @Copilot)
• Bump actions/checkout from 6.0.0 to 6.0.1 #1100
• Bump becheran/mlc from 1.0.0 to 1.2.0 #1098
• Bump actions/upload-artifact from 5.0.0 to 6.0.0 #1099
• Bump actions/download-artifact from 6.0.0 to 7.0.0 #1097
• Bump the other-testing group with 1 update #1101
• Bump Anthropic from 11.0.0 to 12.0.1 #1118
• Bump the other-testing group with 1 update #1124
• Install mono in dev container #1133 by @mikekistler
• Bump Anthropic from 12.0.1 to 12.1.0 #1137
• Bump version to 0.6.0-preview.1 #1141 by @jeffhandley

Acknowledgements

• @333fred @Sergio0694 @Youssef1313 @scutuatua-crypto @tarekgh reviewed pull requests

Full Changelog: v0.5.0-preview.1...v0.6.0-preview.1