# 4.6 — Namespace/resource-name validation by fixture membership (GREEN)

Phase: 4 — Terminal (Surface C)
Stage: GREEN

- [x] Namespace and resource-name arguments validated by **set membership against the mock fixture** (`lib/clusterMock.ts`), not regex/escaping

Done — implemented in [app/api/exec/route.ts](../app/api/exec/route.ts) (`namespaces.find(...)`). Real backend must validate against a live snapshot, not a static fixture — see [REQUIREMENTS.md](REQUIREMENTS.md).