Codex reads an AGENTS.md at the repo root for standing instructions, and that file is useful — but it is static. You write it by hand, it says the same thing on every run, and it knows nothing about what happened in your last three sessions: the migration you half-finished, the dependency that broke the build, the interface you agreed on but never wrote down. Codex CLI keeps a full transcript of each session, yet codex resume only reloads one conversation at a time and only if you remember which one. Everything else is dead weight on disk.
The result is a tax you pay every prompt: re-describe the architecture, re-point at the right files, re-explain the convention you settled yesterday. The knowledge existed. Codex just had no way to consult it.