Codex CLI history: onboarding an engineer

How does someone new find out why this code was written this way?

Why this is hard

A new engineer inherits decisions, not just code. When a large share of the codebase was written with AI, the reasoning lives in conversations rather than in commit messages — and those conversations are on other people's laptops, if they still exist.

What Codex CLI specifically does to you here

Because the rollouts include tool results as well as the conversation, a new engineer can watch a change being built rather than infer it. Date-partitioned directories make 'what happened in this project last spring' a real query.

ls ~/.codex/sessions/*/*/ 2>/dev/null | head

Where Codex CLI keeps this in the first place: ~/.codex/sessions/YYYY/MM/DD/rollout-*.jsonl. Nothing prunes ~/.codex/sessions, so it grows until a person deletes it — usually all of it, usually in a hurry.

What a working answer looks like

A working answer means the reasoning behind a file is reachable from the file, by someone who was not there when it was written.

Start by measuring what you have. npx promptwake doctor reports what every AI tool on the machine is holding and how much of it sits inside a deletion window — no account, writes nothing, sends nothing anywhere. If the conclusion is that the record should not depend on one laptop, that is what PromptWake captures: prompt, response and the resulting diff, local by default and synced into a shared timeline on the paid tiers.