Codex one-month trial: 139-file PR taught review-sized tasks

The author came to Codex already comfortable writing Rails code himself and chose it because he was already a ChatGPT Plus subscriber. His first prompt was broad — build a blog, with a reference URL — and Codex generated the application, article list and detail pages, an admin screen, and tests, with Issue and PR text also written by the AI. The speed was real, but the gap between what the AI produced and what he understood became the central problem.

His response was procedural. He decided to check the AI's plan before implementation, split tasks into units he could review, and keep a log of what he asked for and what changed, a habit he traces to daily reports written during Fjord Boot Camp. He also read official documentation, listed unfamiliar terms such as context, skills, AGENTS.md, CLAUDE.md, agentic, and MCP, and read two books to organize the knowledge.

The Kamal incident shows why that discipline matters. A version-update thread led to a PR that passed RAILS_MASTER_KEY into Kamal's build settings, even though ReNovo runs on Render; leftover rails new configuration files had made Kamal look active. He removed the unnecessary Kamal settings while keeping what the Ruby update and Render build scripts needed, and concluded that a config file's presence says nothing about whether the technology is actually used. His stated goal now is to slow his judgment to a pace he can verify, rather than match the AI's output speed.