Upgrade to MCP C# SDK v0.6.0-preview.1

[jongalloway]

Overview

Update from ModelContextProtocol v0.5.0-preview.1 to v0.6.0-preview.1 and adopt new SDK features.

Release notes: https://github.com/modelcontextprotocol/csharp-sdk/releases/tag/v0.6.0-preview.1

Sub-Issues

• Add icon support for MCP tools #323 - Add icon support for MCP tools
• Adopt telemetry and observability features from SDK v0.6 #324 - Adopt telemetry and observability features from SDK v0.6

Version Update

• Update DotNetMcp.csproj package reference from 0.5.0-preview.1 to 0.6.0-preview.1
• Update doc/sdk-v0.5-compatibility.md to sdk-v0.6-compatibility.md

Key Features to Adopt

1. Fully-Qualified Type Names in Generated Signatures (#1135)

The SDK now uses fully-qualified type names in generated partial method signatures. This should resolve any ambiguity issues we've had with action enums in DotNetMcp.Actions.

• Review if GlobalUsings.cs with global using DotNetMcp.Actions; is still necessary
• Verify generator compatibility with our tool methods

2. CS1066 Suppressor for Optional Parameters (#1110)

The SDK now suppresses CS1066 warnings for MCP server methods with optional parameters.

• Remove any manual suppressions we may have added for this warning
• Verify our tools with optional parameters compile without warnings

3. Incremental Scope Consent - SEP-835 (#1084)

Support for incremental scope consent in authorization flows.

• Evaluate if this applies to our server capabilities
• Document any authorization-related changes

4. Resource Subscribe Improvements (#676)

Resource subscribe is now automatically true if a handler is provided.

• Review DotNetResources.cs and update resource subscription logic if needed
• Simplify any explicit subscription configuration

5. Optimized JSON-RPC Deserialization (#1138)

Single-pass parsing optimization for JsonRpcMessage deserialization.

• Benefit: Improved performance with no code changes required

Testing

• Run full test suite: dotnet test --solution DotNetMcp.slnx
• Verify MCP conformance tests pass
• Test with MCP Inspector
• Test with Claude Desktop integration

Documentation

• Update README.md SDK version reference
• Update any SDK version references in documentation

Breaking Changes Check

Review changelog for any breaking changes:

• s_additionalProperties removed from McpClientTool (#1080) - verify no impact
• Session timeout fix (#1106) - may affect long-running operations

Related

• Upstream release: https://github.com/modelcontextprotocol/csharp-sdk/releases/tag/v0.6.0-preview.1
• Full changelog: modelcontextprotocol/csharp-sdk@v0.5.0-preview.1...v0.6.0-preview.1