OAuth 2.1 + MCP Authorization
The open authorization stack MCP servers are expected to implement.
The current MCP specification (version 2026-07-28) treats MCP servers as OAuth 2.1 resource servers, requiring PKCE (S256) and the RFC 8707 resource parameter, and the 2026 revision added RFC 9207 issuer validation and a shift toward Client ID Metadata Documents; note that OAuth 2.1 is still an IETF Internet-Draft, while RFC 9728 (OAuth 2.0 Protected Resource Metadata, using /.well-known/oauth-protected-resource) is a published Standards Track RFC.
Caveat: OAuth 2.1 has not yet become an RFC; it remains an Internet-Draft referenced by the MCP specification.
Key facts
| Category | Identity & Permission |
|---|---|
| License | Open standard (IETF / MCP specification) |
| Language | N/A (specification) |
| Self-hosted | No |
| Last verified | 2026-10-04 |
Tools in this category
SPIFFE / SPIRE
CNCF-graduated workload identity standard and its reference implementation.
AGNTCY Agent Identity
Linux Foundation-hosted identity service for agents, MCP servers and multi-agent systems.
Agent Identity Protocol (AIP)
An IETF Internet-Draft proposing agentic authentication and policy enforcement, submitted with NVIDIA involvement.