Codex’s core cycle: gather context (read/grep) → act (edit/run in a sandbox) → verify (tests) → repeat until done.

Text user interface — the full-screen interactive app you get after typing codex in your terminal.

Markdown project-memory file Codex reads automatically each session: commands, conventions, guardrails.

The guardrail around Codex’s actions: where it may write and whether it can reach the network (sandbox_mode).

When Codex pauses to ask before acting: untrusted, on-request, or never.

How long the model deliberates before acting: low, medium, or high.

Model Context Protocol — an open standard connecting Codex to external tools and data (GitHub, docs, databases).

Work delegated to Codex cloud: runs isolated on OpenAI’s infrastructure, in the background, and opens a pull request.

Running Codex non-interactively (e.g. codex exec) for scripts and CI — no session prompts.

A financing statement filed to perfect a lender’s security interest in a debtor’s collateral.

The UCC rule requiring a registered organization’s exact legal name on a filing; a wrong name can be seriously misleading.