A merge-request review by GitLab Duo Code Review costs us about $0.20. We're a small team of developers, so $1 for ~5 MR reviews gets expensive quickly. We had a ChatGPT subscription on the team budget already. The obvious move was to point the subscription we paid for at the reviews we wanted to automate. But Duo wouldn't let me. It only accepts pay-per-token providers, runs a couple model generations behind, and is closed to the prompt and workflow tweaks I wanted. So I built our team a replacement. It turned into a more interesting rabbit hole than I expected. About three days end to end (Friday plus the weekend): one day for a working proof of concept, one day for the security work, and two half-days for polish. The security work was the most fun part, because running Codex's danger-full-access mode on a locked-down OpenShift cluster turned out to be the only shape that worked there. Driving Codex from a ChatGPT subscription OpenAI's @openai/codex-sdk is the supported automation surface.…