Over the past five months the team built an internal beta without writing a single line of code by hand. Every artifact—application logic, tests, CI config, documentation and observability—was generated by Codex. The experiment aimed to shrink development time rapidly to roughly one‑tenth of a traditional effort, proving that engineers can focus on intent while agents execute.

The first commit landed in late August 2025 using a Codex‑driven CLI built on GPT‑5. After five months the repository holds on the order of million lines of code and 1,500 pull requests merged. Three engineers drove the process, averaging 3.5 PRs per day, and throughput rose as the team expanded to seven engineers, serving hundreds of internal power users daily.

Human engineers spent their time designing scaffolding, indexing repository knowledge and prompting agents to fill gaps. By exposing UI, logs and metrics directly to Codex, agents could launch isolated worktrees, query LogQL and PromQL, and validate performance targets without human copy‑paste. The project demonstrates that an agent‑first workflow can produce a production‑grade codebase consistently at scale, making code generation a viable engineering strategy.