Codex Imagegen

Codex Imagegen

Generate images with Codex's built-in $imagegen skill and land them in the project, keeping ~/.codex/generated_images/ from silently growing (it accumulates ~10MB per generation and is never cleaned by Codex itself).

Everything is driven by one bundled script that survives plugin version bumps and works on machines without the codex plugin (it falls back to codex exec).

Prerequisites

Either of these (the script auto-detects which is present):

• Codex plugin in Claude Code — /plugin marketplace add openai/codex-plugin-cc, then /plugin install codex@openai-codex (Full guide: https://github.com/openai/codex-plugin-cc#install).
• Codex CLI (any agent) — npm i -g @openai/codex, then codex login.

Auth is OpenAI/ChatGPT-account backed. Without one of these the script exits with code 3 and prints these install steps.

Workflow

1. Determine the destination

• If the user named a destination folder, use it.
• Otherwise default to .codex-image/ at the project root (the script creates it).
• If a file the user wants to create already exists at the destination (same intended name), ask the user before overwriting — never silently replace.

2. Compose the image prompt

Write plain prompt text — do NOT include the $imagegen token; the script prepends it safely (a $imagegen typed into a double-quoted shell string gets expanded to an empty string and the skill silently never triggers — the script exists partly to make that mistake impossible).

Include in the prompt text:

• A clear description of the image (subject, style, mood, colors).
• Desired dimensions or aspect ratio. The raw model output is ~1254px square; Codex resizes/crops to what you ask, so always state it (e.g. "1200x630 landscape" for a featured image).
• The exact output filename(s), e.g. "save it as featured-image.png".
• Number of variants if the user wants more than one.

The script appends the destination directory instruction automatically.

3. Run the script

bash <skill-dir>/scripts/codex-imagegen.sh --dest "<destination-dir>" "<prompt text>"

• The script needs network access (Codex calls OpenAI). In Claude Code, run it with dangerouslyDisableSandbox: true so the Bash sandbox doesn't block the call. In other agents/shells, run the bash command normally.
• Set a generous timeout (600000 ms / 10 min). A generation takes 2–5 minutes.
• Leave model/effort alone; Codex defaults handle imagegen fine.

The script resolves the runtime itself: it globs for the codex plugin's codex-companion.mjs across all marketplaces and versions (newest wins), and falls back to codex exec --sandbox workspace-write when the plugin is absent. If neither exists it exits with install instructions — relay them to the user.

4. Read the output

The script prints:

• RUNTIME= — which path it used (plugin companion or codex CLI).
• GENERATED_FILES: followed by the new file path(s) at the destination. If Codex generated but forgot to copy to the destination, the script moves the files there itself.
• CLEANUP= — whether this run's ~/.codex/generated_images/<thread-id>/ folder was removed. It is only deleted after a file is confirmed at the destination; otherwise the originals are kept so nothing is ever lost.
• LEFTOVER_THREAD_FOLDERS= / LEFTOVER_TOTAL_SIZE= — pre-existing thread folders from past sessions (TUI runs, etc.) that the script never touches.

Show the user what was made — in Claude Code, view the file(s) with the Read tool; other agents can open the path(s) printed under GENERATED_FILES:.

5. Offer a sweep when leftovers are piling up

If LEFTOVER_THREAD_FOLDERS is more than a handful (or the size is large), tell the user the count and size the script reported (e.g. "there are N old generation folders using X MB") and offer to clear them. Only after they confirm:

bash <skill-dir>/scripts/codex-imagegen.sh --sweep

Never sweep unprompted: old folders may hold originals from TUI sessions the user hasn't copied out yet.

Failure modes

• Auth error ("refresh token was revoked" / "log out and sign in again"): Codex needs an interactive re-login. Ask the user to run ! codex logout && codex login.
• No image at destination and no new thread folder: the turn likely failed before generation — re-read the script output for the Codex error and report it. The prompt may also have been refused (content policy); rephrase and retry once.
• Exit code 3: no runtime found on this machine. Relay the script's install steps — either the codex plugin (/plugin marketplace add openai/codex-plugin-cc then /plugin install codex@openai-codex; Full guide: https://github.com/openai/codex-plugin-cc#install) or the Codex CLI (npm i -g @openai/codex then codex login).