MCP · Profile

MCP Authorization

The OAuth 2.1 profile that MCP clients and servers follow so that a client can obtain and present access tokens to an MCP server over HTTP transports.

PublishedSpecification revision 2026-07-28Canonical documentmcp-authorization

Revisions

2026-07-282026-07-28currentWhat changed since 2025-11-25
Deprecates Dynamic Client Registration in favour of Client ID Metadata Documents, requires RFC 9207 issuer validation on authorization responses, keys stored client credentials by issuer, requires application_type on DCR requests, and removes session identifiers from the transport. Splits the authorization text into separate pages for discovery, client registration and security considerations.
2025-11-252025-11-25superseded
Makes OAuth Client ID Metadata Documents the recommended client registration method and adds Enterprise-Managed Authorization (ID-JAG) as an extension.

Relations 11

MCP Authorization builds on 5

Proof Key for Code Exchange by OAuth Public Clients (PKCE)publishedPKCE with S256 is required for every authorization request.Source
OAuth 2.0 Authorization Server MetadatapublishedClients discover the authorization server's endpoints from its metadata.Source
Resource Indicators for OAuth 2.0publishedClients name the MCP server with the resource parameter so tokens are audience-bound.Source
OAuth 2.0 Authorization Server Issuer IdentificationpublishedRevision 2026-07-28 requires clients to validate the iss parameter when present.Source
OAuth 2.0 Protected Resource MetadatapublishedAn MCP server announces its authorization servers through protected resource metadata.Source

MCP Authorization profiles 1

The OAuth 2.1 Authorization FrameworkWG draftMCP authorization is a profile of OAuth 2.1 for MCP clients and servers.Source

MCP Authorization references 3

OAuth 2.0 Dynamic Client Registration ProtocolpublishedDynamic Client Registration remains an option, deprecated in revision 2026-07-28.Source
OAuth Client ID Metadata DocumentWG draftClient ID Metadata Documents are the recommended registration method.Source
OpenID Connect Discovery 1.0publishedAn authorization server may publish its metadata as an OpenID Provider configuration instead.Source

MCP Authorization is built on by 1

MCP Enterprise-Managed AuthorizationpublishedAn extension of the base authorization flow for enterprise-managed MCP clients.Source

MCP Authorization is referenced by 1

AuthZEN COAZ Binding for the Model Context ProtocolWG draftAdds a policy decision step for tool calls on top of the token-based authorization MCP defines.Source

Defines in the shared model

Features of revision 2026-07-28 that the MCP auth atlas observes, with the level the revision puts on them.

Metadata issuer matches the discovery URLMUSTAuthorization server · Discovery · Authorization Server Discovery › Authorization Server Metadata Discovery
Authorization server metadata discoverableMUSTAuthorization server · Discovery · Authorization Server Discovery › Authorization Server Metadata Discovery
Protected Resource Metadata servedMUSTMCP server · Discovery · Authorization Server Discovery › Authorization Server Location
PRM lists an authorization serverMUSTMCP server · Discovery · Authorization Server Discovery › Authorization Server Location
PRM lists scopes_supportedMAYMCP server · Discovery · Authorization › Scope Selection Strategy
PRM reachable at a well-known URIMUSTMCP server · Discovery · Authorization Server Discovery › Protected Resource Metadata Discovery Requirements
resource_metadata in the 401 challengeMUSTMCP server · Discovery · Authorization Server Discovery › Protected Resource Metadata Discovery Requirements
Client ID Metadata Documents supportedSHOULDAuthorization server · Registration · Client Registration › Client ID Metadata Documents
Dynamic Client Registration offeredMAYAuthorization server · Registration · Client Registration › Dynamic Client Registration
Documented pre-registration pathSHOULDAuthorization server · Registration · Client Registration › Pre-registration
Credentials stored per issuerMUSTClient · Registration · Client Registration › Credential Storage
application_type on DCR requestsMUSTClient · Registration · Client Registration › Dynamic Client Registration
Issuer identifier in authorization responsesSHOULDAuthorization server · Authorization · Authorization › Authorization Response Validation
PKCE with S256 advertisedMUSTAuthorization server · Authorization · Security Considerations › Authorization Code Protection
Exact iss comparisonMUSTClient · Authorization · Authorization › Authorization Response Validation
PKCE on every authorization requestMUSTClient · Authorization · Security Considerations › Authorization Code Protection
Scope union on step-upSHOULDClient · Authorization · Authorization › Scope Challenge Handling
403 insufficient_scope for step-upSHOULDMCP server · Authorization · Authorization › Scope Challenge Handling
Scope in the WWW-Authenticate challengeSHOULDMCP server · Authorization · Authorization › Scope Selection Strategy
Refresh token rotation for public clientsMUSTAuthorization server · Tokens · Security Considerations › Token Theft
Resource indicators honouredMUSTAuthorization server · Tokens · Security Considerations › Token Audience Binding and Validation
resource parameter on token requestsMUSTClient · Tokens · Security Considerations › Token Audience Binding and Validation
No offline_access in advertised scopesSHOULDMCP server · Tokens · Authorization › Refresh Tokens
401 for missing or invalid tokensMUSTMCP server · Tokens · Authorization › Token Handling
Audience validationMUSTMCP server · Tokens · Security Considerations › Access Token Privilege Restriction
Bearer token only in the Authorization headerMUSTMCP server · Tokens · Authorization › Access Token Usage
All endpoints served over HTTPSMUSTAuthorization server · Transport · Security Considerations › Communication Security
No token passthrough to upstream APIsMUSTMCP server · Delegation · Security Considerations › Access Token Privilege Restriction
Per-client consent on proxy serversMUSTMCP server · Consent · Security Considerations › Confused Deputy Problem