chatgpt-imagegen

name

chatgpt-imagegen

description

Generate raster images (PNG/JPEG/WebP) using the user's ChatGPT subscription via a local one-file Python CLI — no OPENAI_API_KEY, no gateway, no daemon. Use when an agent needs to create a brand-new bitmap asset for the current project (photos, illustrations, icons, hero banners, mockups, sprites, concept art) and the output should be a bitmap file saved into the workspace. Do not use when the task is better solved by editing existing SVG/vector assets, writing code-native graphics (HTML/CSS/canvas), or extending an established repo icon system.

chatgpt-imagegen — agent skill

A standalone Python CLI that produces images via the user's ChatGPT subscription. It is a thin wrapper around ChatGPT's internal image_generation Responses-API tool, the same one the Codex CLI invokes. No API key, no network service, no extra config.

The script lives at $CLAUDE_SKILL_DIR/scripts/chatgpt-imagegen.py — always call it by that path.

Prerequisites

The user must have run, once, ever:

npm i -g @openai/codex
codex login    # opens browser to sign in to ChatGPT

That writes ~/.codex/auth.json, which this skill reads. If the file is missing, tell the user to run the two commands above and stop. Do not try to authenticate any other way.

No OPENAI_API_KEY is required — and setting one will not help. This is the subscription path, not the API path.

When to use

• The user asks for a new photo, illustration, icon, hero banner, sprite, cover image, infographic, product mockup, concept art, or any other bitmap deliverable for the current project.
• The user is happy with subscription-tier quality (medium quality, no native transparent backgrounds — see Limits below).
• The deliverable is intended to be saved into the repo or build inputs.

When not to use

• The user wants an SVG icon that matches an in-repo vector set — edit those instead.
• The task is better solved with code (HTML/CSS, canvas, Mermaid, PlantUML).
• The user already has an image on disk and wants to edit it — this skill is generate-only.
• The user explicitly needs true quality=high or background=transparent — the subscription path caps quality at medium and rejects transparent. Tell the user to use the official /v1/images/generations API with their OPENAI_API_KEY for those cases.
• The deliverable will be served to end users (e.g. a public service generating images for visitors) — that violates OpenAI's ToS for personal subscriptions. Refuse and explain.

How to invoke

python "$CLAUDE_SKILL_DIR/scripts/chatgpt-imagegen.py" "<prompt>" [options]

$CLAUDE_SKILL_DIR is set by the active agent harness when the skill loads. Always use this variable — never hardcode the path or rely on the script being on $PATH.

Useful flags:

Flag	When to use
-o PATH	Always use when you know where the file should go in the repo.
--ref PATH	Reference image for style/composition guidance (repeatable, up to 5).
--size 1024x1024	Square icons / logos (verified)
--size 1536x1024	Landscape hero banners, social cards (verified)
--size 1024x1536	Portrait covers, mobile splashes (verified)
--size 1792x1024	Wide landscape, cover images (verified)
--size 3840x2160 or similar	4K landscape (forwarded as-is; backend may reject — fall back to a smaller verified size on failure)
--format webp	Smaller files for web assets
--quiet	Use this in agent contexts so stdout is only the saved path

The script prints just the saved path on stdout when --quiet is set; progress goes to stderr. Capture it with:

OUT=$(python "$CLAUDE_SKILL_DIR/scripts/chatgpt-imagegen.py" "..." --quiet)

Save-path policy

1. Always save into the workspace, never into /tmp, $HOME, or ~/.codex/....
2. If the user named a destination, pass it via -o.
3. If they didn't, pick a sensible subdirectory: assets/, public/, static/, docs/img/, web/img/, assets/brand/, etc. Default to assets/generated/ only if nothing better fits.
4. Don't overwrite existing files unless the user asked. With -o the script overwrites silently; without -o it auto-numbers (name.png, name-2.png).
5. After saving, echo the final path back to the user.

Workflow

1. Clarify the prompt enough to write 1–3 sentences: subject, style, composition, mood, constraints. Don't over-augment when the user's prompt is already specific.
2. Pick size and format based on intended use (see table above).
3. Pick the output path inside the workspace.
4. Run python "$CLAUDE_SKILL_DIR/scripts/chatgpt-imagegen.py" "<prompt>" -o <path> --size <wxh> --quiet.
5. Inspect the result if you can (e.g. with a view_image tool or by reading the file). If clearly wrong, iterate with a single targeted prompt change — do not loop blindly (each call costs subscription quota).
6. Report the saved path plus the final prompt used.

Limits

• Image quality is chosen by the backend; this skill has no --quality flag, and the subscription path does not honour explicit quality requests reliably. Don't promise a specific quality level to the user. If they need explicit quality=high, route them to the official /v1/images/generations API with their own OPENAI_API_KEY.
• background: transparent is not supported on the subscription path.
• A single image takes 15–40 s.
• Parallel execution is supported — the backend handles ≥4 concurrent requests with no serialization or 429s on a Plus account. If the user asks for several distinct assets, you may fire the script in parallel (e.g. shell & + wait). Do not loop blindly for "variants of the same prompt" — that just burns quota; iterate on the prompt instead.
• Subscription quota is shared with the user's interactive ChatGPT use. Don't bulk-generate (>10 images / minute sustained) without permission — you'll hit per-day caps.

Error handling

Symptom	Cause	Fix
~/.codex/auth.json not found	Codex CLI never signed in	Tell user to run npm i -g @openai/codex && codex login
no ChatGPT OAuth access_token in ~/.codex/auth.json	Only an API key is present, not a subscription OAuth token	Tell user to run codex login; an OPENAI_API_KEY value in that file is not a substitute
HTTP 400 requires a newer version of Codex	local codex CLI is outdated	Tell user to run npm i -g @openai/codex@latest
HTTP 401 / HTTP 403 then refresh works	Token expired and refresh succeeded	No action needed — script auto-retried
refresh_token is no longer valid — run codex login again	Refresh token revoked or rotated	Tell user to run codex login again
stream exceeded total timeout budget	Backend stuck or slow	Retry; if persistent, pass --timeout 300
no image returned. events seen: ...	Model decided not to call the tool	Rephrase prompt to explicitly say "Use the image_generation tool to render…"
HTTP 429	Subscription rate-limited	Wait a few minutes; do not retry in a loop
warning: --format=X but FILE.Y has .Y extension	-o extension disagrees with --format	Fix the path or the format flag; the file IS written with the format you specified

Internals (for maintainers / debugging)

• Reads ~/.codex/auth.json for access_token, account_id, refresh_token.
• Reads ~/.codex/version.json for the version header.
• POSTs to https://chatgpt.com/backend-api/codex/responses with tools: [{"type": "image_generation"}].
• Streams the SSE response, extracts the image_generation_call output item, base64-decodes item.result, writes it to disk.
• Auto-refreshes the OAuth token on 401/403 via https://auth.openai.com/oauth/token using client_id=app_EMoamEEZ73f0CkXaXp7hrann. The refreshed token is persisted back to auth.json.

Source

Adapted from leeguooooo/chatgpt-imagegen (MIT). Script bundled at scripts/chatgpt-imagegen.py — no system install needed.