The OpenAI CLI is a Go‑based command‑line tool that lets developers invoke the OpenAI REST API directly from the terminal or embed calls in shell scripts. After installing the binary from GitHub releases (or via `brew install openai/tools/openai`) and ensuring Go 1.26+ is present, the executable is placed in $HOME/go/bin and added to PATH. It requires an OPENAI_API_KEY environment variable for regular calls and an OPENAI_ADMIN_KEY for admin endpoints such as `openai admin organization usage completions --start-time 1735689600 --end-time 1735776000 --bucket-width 1d`. Core functionality includes image generation (`openai images generate --prompt "..."`), file upload and download (`openai files upload …`, `openai files download …`), and batch processing (`openai files upload requests.jsonl --purpose batch` followed by `openai batches create … --completion-window 24h` and `openai batches wait …`). Output can be formatted as JSON, JSONL, raw, YAML, or transformed with `--transform` using GJSON; errors are emitted to stderr and can be inspected via `--format-error`. The tool also supports shell completion, command insertion, and automatic update checks that can be disabled with OPENAI_CLI_NO_UPDATE_CHECK=1.