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MCP-AUT-009

offline_access absent from scopes_supported / challenge scope

MCP Servers (Protected Resources) SHOULD NOT include offline_access in WWW-Authenticate scope or Protected Resource Metadata scopes_supported.spec anchor

How to fix this

Remove `offline_access` from `scopes_supported` and from the challenge scope. Requesting it grants refresh tokens the resource server does not need.

How the validator checks this

Probe P8.2, against a streamable-http server on the modern protocol. What it reports:

pass
offline_access is not advertised in the challenge
info
Challenge advertises offline_access. Refresh-token lifetime is the authorization server's concern; a resource server SHOULD NOT ask for it.

Quoted from the probe that runs this check, so it cannot drift from what the validator actually reports.

This rule is checked deterministically: a fail here is a certain violation, not an inference.

Checked in the same request as MCP-AUT-002, MCP-AUT-003.

Check your own server against this rule

The validator makes real protocol requests and reports this rule as pass, warn or fail alongside the other 78. Validate a server or read how the check works.

Other Authorization rules

  • MCP-AUT-001Unauthenticated request returns 401 with WWW-Authenticate resource_metadata
  • MCP-AUT-002RFC 9728 Protected Resource Metadata is served and valid
  • MCP-AUT-003PRM resource equals the canonical server URI
  • MCP-AUT-004Each listed authorization server exposes RFC 8414 or OIDC discovery metadata
  • MCP-AUT-005AS advertises authorization_response_iss_parameter_supported: true
  • MCP-AUT-006WWW-Authenticate includes a scope parameter
  • MCP-AUT-007Insufficient scope returns 403 with error="insufficient_scope"
  • MCP-AUT-008Tokens with a foreign audience are rejected
  • MCP-AUT-010AS advertises S256 in code_challenge_methods_supported
  • MCP-AUT-011AS supports Client ID Metadata Documents, not DCR alone