OpenAI CLI is an official tool for calling REST APIs such as Responses, images, files, and batches from a terminal. Its purpose differs from Codex CLI, which carries out coding work. Its default output is designed for people to read, so scripts should explicitly request JSON or JSONL. It also separates the roles of regular API keys and administrative keys. Safeguards prevent implicit file reads from untrusted standard input. Official documentation advises checking the installation path because the executable can be confused with the same-named command from the existing Python SDK.