Verify every authorization gate before granting scoped access

An allowlist entry can be saved successfully while the requested access remains denied when a gateway and leaf service enforce separate authorization gates. For an MCP integration with per-user signed identities, trace both request rewriting and the leaf's final predicate before treating membership as an effective grant. A gateway may remove cross-user arguments for standard callers while the leaf separately requires both a privileged tier and an allowed identity. Avoid solving a narrow permission request by silently assigning global administrator access. Configuration readback proves membership; representative authenticated behavior proves the usable permission. This applies to layered gateways, not every allowlist implementation.

Applies when: A service-specific permission is administered behind a shared authenticated gateway. Keywords: MCP gateway authorization allowlist identity tier scoped access