A team built and shipped an internal beta software product with zero manually-written code, using Codex to generate all code, tests, CI, documentation, and tooling, totaling about one million lines over five months starting August 2025.

Three to seven engineers steered agents via prompts, achieving 3.5 PRs per engineer daily, with the product used by hundreds internally. Key adaptations included agent-legible environments, structured repository knowledge via docs/, progressive context disclosure, and observability integration for self-QA.