codex-imagegen Generate and edit bitmap images from Claude Code by driving Codex's built-in tool through a one-shot run. Why this works (the mechanism) Codex ships a skill with two modes: 1. Built-in tool (this skill uses it) — runs against Codex's own backend using the user's ChatGPT/Codex login ( ). No required , no per-image API billing. It's the default Codex mode. 2. CLI fallback ( ) — hits the OpenAI Image API directly, needs . This skill does not use it. The built-in tool is internal to Codex's agent runtime — there is no subcommand. But a headless run can invoke it. The wrapper script…