Fabien Sanglard

A retrospective on id Software's 1996 Quake shareware CD-ROM, which bundled encrypted full versions of id games that buyers could unlock via a phone order system built by TestDrive Corp. The scheme relied on security by obscurity: the on-disc unlock program generated serial codes locally, so GNOMON cracked it in 39 days, aided by plaintext files and bugs. The experiment failed commercially, leaving id with ~150,000 unsold CDs.

The author recounts moving from unusable LLM code in 2025 to productive agentic coding in 2026, then shares the agent.md file they built to encode recurring code-review corrections as prompt rules: concise comments, no magic numbers, early returns, private-by-default visibility, layered architecture, commit conventions, and test-first bug fixes. It reduces repetition and frees review time for architecture, but is no magic bullet — hallucination and verification remain, and 'context dilution' degrades adherence, mitigated by short sessions and reloading agent.md.