Model Context Protocol publishes 2025-11-25 specification
One-year anniversary spec adds async Tasks, improved OAuth support, and extensions; first revision with backward-compatibility guarantees.
The 2025-11-25 revision is the first Model Context Protocol (MCP) spec update to ship a backward-compatibility guarantee, marking the protocol's transition from rapid iteration to stable infrastructure one year after its original release (2024-w48-standards-anthropic-mcp). Async Tasks address the long-running-operation gap that earlier MCP servers worked around with polling. OAuth refinements align MCP authentication with the OpenID Foundation's identity work (2025-w41-identity-openid-foundation-ai-whitepaper). The release precedes MCP's adoption as a flagship project of the Linux Foundation's Agentic AI Foundation (2025-w50-standards-linux-foundation-aaif) by two weeks, and the spec is the transport that the Stripe-OpenAI Agentic Commerce Protocol (2025-w40-payments-stripe-openai-acp-instant-checkout) and Google's AP2 (2025-w38-standards-google-ap2-protocol) both compose on top of. The anniversary timing makes the release an explicit governance checkpoint for the protocol.