COAZ-MCP: bind permits to evaluated operations

[FutureEnterprises]

Summary

• apply known rewrites and normalizations before mapping selection and evaluation
• require the PEP to re-evaluate or refuse when the method, selected mapping, or binding input values change before forwarding
• state explicitly that an AuthZEN decision does not cover source inputs omitted by the selected mapping

Closes #603.

Why

Issue #603 identifies a time-of-check to time-of-use gap between the operation evaluated by the PDP and the operation ultimately forwarded or executed.

The added authorization-granularity text records a separate boundary found while reproducing that issue. A valid mapping can intentionally omit an input. Two source operations that differ only in that input can then construct the same AuthZEN request and receive the same decision. That is acceptable for coarse-grained authorization, but the omitted input was not evaluated by the PDP and must not be represented as if it were.

Validation

• kramdown-rfc2629 render passed
• xml2rfc HTML render passed
• git diff --check passed
• source-pinned external reproduction: 9 of 9 cases passed
• Vitest reproduction: 7 of 7 tests passed

Reproduction artifact:
https://github.com/emiliaprotocol/emilia-protocol/blob/feat/authzen-coaz-mapping-integrity-20260823/conformance/composition/coaz-translation-v0.1/AUTHZEN-CONTRIBUTION.md

Claim boundary

The reproduction uses a mapping and toy PDP created for the corpus. It does not claim that a deployed AuthZEN, COAZ, MCP, gateway, or PDP product is vulnerable. CAID is demonstrated only as an optional relying-party content-correlation mechanism and is not a normative dependency of this patch.

IPR

The OpenID Foundation Contribution Agreement for EMILIA Protocol, Inc. and the AuthZEN Working Group was completed and countersigned on August 21, 2026.

[alexolivier]

This is a great addition - thank you!