How a 'Fails Closed' License Inventory Endpoint Prevents AI-Generated Release Bugs

A software engineering case study demonstrates how to build a release inventory endpoint that correctly classifies third-party package licenses without relying on a coding agent's guesses. The approach requires freezing a classification table and response rules in writing before any implementation code is written, ensuring unknown or ambiguous licenses trigger an HTTP 422 error rather than being silently labeled as permissive. Each dependency must be assigned to exactly one of four classes — permissive, weak copyleft, strong copyleft, or unknown — with the unknown class always blocking a release. The core classifier is kept as a pure function, separate from the HTTP layer, so bad labels cannot be hidden by the server logic. The key lesson is that a short, reviewer-readable rules document written before code generation prevents AI-drafted handlers from quietly inventing or dropping license obligations.