v0.20.0

Added

• Support W3C Trace Context Propagation via _meta per SEP-414 (#397)
• Support OAuth client_credentials grant in OAuth client (#399)
• Add annotations field to MCP::Resource and MCP::ResourceTemplate per MCP specification (#403)

Changed

• Re-run OAuth flow on 403 insufficient_scope (step-up) (#368)
• Speed up Tool::Schema validation by 5x to 100x (#369)
• Use JSON-RPC error envelope for StreamableHTTPTransport errors (#371)
• Pin RFC 8414 default well-known suffix per SEP-2351 (#395)
• Default missing MCP-Protocol-Version to 2025-03-26 in StreamableHTTPTransport (#392)

Fixed

• Preserve the request ID in invalid request error responses (#400)
• Standardize Resource Not Found errors on -32602 with URI data per SEP-2164 (#402)