Access-control tests must exercise the real registry and permissive drift

Access-control tests should exercise the committed registry and deliberately permissive configuration drift, alongside isolated fixtures. A fixture with an admin-only allowlist can pass while the deployed registry independently grants standard callers access. Place mandatory source restrictions in the shared authorization predicate used by both listing and invocation, and keep the registry and documentation consistent.

Applicability and limits: this protects an explicit source-level invariant; it is not a reason to hard-code every configurable source policy. A passing local test does not prove deployment or revoke definitions cached by a client.

Applies when: a mandatory access restriction must survive configurable gateway registries and client tool discovery. Keywords: MCP gateway authorization registry admin standard discovery config drift tests