Release v0.3.0

[atesgoral]

Release v0.3.0

Summary

This PR prepares the v0.3.0 release of the MCP Ruby SDK, updating the version and documenting all changes since v0.2.0.

Changes

• Update version to 0.3.0 in lib/mcp/version.rb
• Update CHANGELOG.md with comprehensive v0.3.0 release notes including:
  • Tool output schema support with validation
  • HTTP client transport layer
  • Tool annotations validation
  • Server instructions support
  • Protocol version improvements
  • Various bug fixes and documentation enhancements

Release Notes

Added

• Tool output schema support with comprehensive validation (Validate tool annotations value #122)
• HTTP client transport layer for MCP clients (Add basic http client support #28)
• Tool annotations validation for protocol compatibility (Validate tool annotations value #122)
• Server instructions support (Add instructions support to MCP::Server #87)
• Title support in server info (Add title to serverInfo #119)
• Default values for tool annotation hints (Set default values for ToolAnnotations hints #118)
• Notifications/initialized method implementation (implements the notifications/initialized method #84)

Changed

• Make default protocol version the latest specification version (Set default protocol version to the latest specification #83)
• Protocol version validation to ensure valid values (Validate protocol_version value #80)
• Improved tool handling for tools with no arguments (Fix tools with no args #85, Account for missing arguments #86)
• Better error handling and response API (Add title to tools, prompts and resources #109)

Fixed

• JSON-RPC notification format in Streamable HTTP transport (Fix JSON-RPC notification format in Streamable HTTP transport #91)
• Errors when title is not specified (Fix errors when title is not specified #126)
• Tools with missing arguments handling (Account for missing arguments #86)
• Namespacing issues in README examples (Fix namespacing in README examples #89)

Verification

• ✅ All tests pass (251 runs, 649 assertions, 0 failures)
• ✅ RuboCop linting passes with no offenses
• ✅ Gem builds successfully

Ready for release to RubyGems.

[koic]

Thank you, Ateş 🎉