Authorization server · Authorization

Issuer identifier in authorization responses

The authorization server returns the iss parameter on authorization responses (RFC 9207) and advertises authorization_response_iss_parameter_supported: true.

mcp.as.iss-param

In revision 2026-07-28

Level
SHOULD
Defined in
Authorization › Authorization Response ValidationMCP Authorization 2026-07-28
Party
Authorization server
Observable
passive Observable by reading published metadata, without any request to the server.

Level by revision

RevisionLevelSection
2026-07-28currentSHOULDAuthorization › Authorization Response Validation
2025-11-25not defined

Adoption

Across the listed servers

Supported 9

Unsupported 25

Unknown 2

Not applicable 3