chatgpt-imagegen — agent skill

A standalone Python CLI that produces images via the user's ChatGPT subscription. No API key, no network service, no extra config. It has two backends that hit different OpenAI usage buckets — pick with --backend.

Backends

Default is auto (--backend auto, or CHATGPT_IMAGEGEN_BACKEND): it tries web first because that spares the Codex-usage limit, and falls back to codex only when web is unavailable — i.e. chrome-use isn't installed, the browser isn't reachable, or chatgpt.com isn't logged in. The two not-set-up cases are handled explicitly:

• Browser not logged in / chrome-use missing → auto silently falls back to codex (a one-line notice prints to stderr). If codex is also not set up, it exits naming both fixes.
• codex not logged in (~/.codex/auth.json absent) → auto still uses web; codex is only the fallback.

Auto does not fall back to codex if web was reachable but the generation itself failed after submitting — that would spend the very bucket auto-mode protects. In that case it errors and tells you to rerun with --backend codex if you want the Codex-usage path. Force a single backend with --backend web or --backend codex.

Prerequisites

For the default web backend: the user must have chrome-use (formerly agent-browser-stealth; older installs expose the same binary as agent-browser / abs) and its extension connected to a Chrome that is signed in to chatgpt.com. chrome-use specifically is required — its real-logged-in-Chrome connect is what passes Cloudflare's bot-detection; a plain headless driver will not. The "Temporary Chat" mode disables image generation, so this backend always opens a regular chat.

Install policy — never install chrome-use for the user

If chrome-use is not installed, do not install it on your own initiative:

1. Generate anyway via the codex fallback (auto mode does this by itself) — the task comes first.
2. Add a single gentle tip to your reply, e.g.: "提示：装上 chrome-use 后，出图会走你已登录的 ChatGPT 浏览器，不消耗 Codex 额度。想配的话我可以一步步带你装好（含浏览器插件）。" — and stop there.
3. Only when the user explicitly says yes, walk them through the guided setup below, step by step, verifying each step before the next.

Guided setup (opt-in only):

# 1. Install the CLI (no npm, no token — provides `chrome-use`)
curl -fsSL https://raw.githubusercontent.com/leeguooooo/chrome-use/main/install.sh | sh
# 2. Register the native-messaging host
chrome-use extension install
# 3. Add the Chrome extension, then restart Chrome:
#    https://chromewebstore.google.com/detail/agent-browser-stealth/knfcmbamhjmaonkfnjhldjedeobeafmk
# 4. Sign in to https://chatgpt.com in that Chrome
# 5. Verify: a quick `chatgpt-imagegen "test" --backend web` should print "using current Chrome (relay)"

• Repo: https://github.com/leeguooooo/chrome-use
• The chrome-use skill (chrome-use skills get core) covers the extension-connect flow in depth.

For the codex backend: 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 the codex backend reads. No OPENAI_API_KEY is required for either backend — 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

"<skill-dir>/chatgpt-imagegen" "<prompt>" [options]

When this skill is installed via npx skills add leeguooooo/chatgpt-imagegen -g, the bundled chatgpt-imagegen script sits next to this SKILL.md. Call it by its absolute path — that is the most reliable way and never depends on $PATH. If your agent harness exposes a variable that points to the skill's install directory, use it; otherwise expand the path you read this file from.

If the user has separately put chatgpt-imagegen on $PATH (Option B in the README), you can also just run chatgpt-imagegen "<prompt>" directly.

Useful flags:

The script prints just the saved path on stdout in every mode; the readable progress timeline and any errors go to stderr, so OUT=$(chatgpt-imagegen "..." --quiet) captures only the path while you still see the timeline. Each timeline line is stamped with elapsed seconds ([ 12.3s] generating), so a slow run is legible and a stall is obvious.

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 chatgpt-imagegen "<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 typically takes 15–60 s, but large or detailed ones occasionally run 2–3 min. The default --timeout is 300 s to cover this; a genuine hang is caught sooner by the --stall-timeout idle window (default 120 s).
• Per-backend concurrency caps (cross-process, flock slot pool; excess runs queue safely, waiters print "waiting…", and --timeout starts only once a slot is acquired): web = 1 (the page surface rate-limits aggressively — "Too many requests"; also one shared Chrome), codex = 4 (measured safe on Plus, capped so big fan-outs can't trip the account limiter). Override via CHATGPT_IMAGEGEN_WEB_CONCURRENCY / CHATGPT_IMAGEGEN_CODEX_CONCURRENCY (0 = unlimited). For parallel batches use --backend codex + shell & + wait; firing parallel web runs is safe but executes one at a time. 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

Internals (for maintainers / debugging)

web backend (run_web)

• Shells out to chrome-use against a session-named Chrome tab group.
• Opens a regular https://chatgpt.com/ chat (Temporary Chat disables the image tool).
• Resolves the target ChatGPT Project from inside the authenticated page (undocumented endpoints, probed live): GET /backend-api/gizmos/snorlax/sidebar lists projects (a project is a gizmo with id g-p-…); POST /backend-api/projects {name, instructions} creates one. It then navigates to https://chatgpt.com/g/<g-p-id>/project and submits from that composer, which files the conversation inside the project. Any failure degrades to a plain chat with a stderr warning.
• Submits via keyboard type + Enter — not fill: the composer is a ProseMirror/React contenteditable, and fill mutates the DOM without firing the input events React needs, so the send button stays bound to empty state. A send-button click is the fallback.
• Polls page state via eval: waits until the streaming/stop control is gone AND a brand-new <img> (src matching estuary/content|files/download|oaiusercontent) is present and stable across two reads. The img scan is scoped to main img (the tab's own conversation thread) — ChatGPT pushes an "Image created" toast with a matching thumbnail into any open tab when another conversation finishes an image, and a document-wide scan grabs that sibling's image (issue #7). The generated img is NOT inside [data-message-author-role="assistant"], so <main> is the right scope.
• Downloads the bytes with an in-page fetch(src, {credentials:'include'}) → base64, so the browser's own session cookies authorize the signed asset URL. No tokens leave the browser.

codex backend (run_codex)

• 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, base64-decodes the image_generation_call result.
• Auto-refreshes the OAuth token on 401/403 via https://auth.openai.com/oauth/token (client_id=app_EMoamEEZ73f0CkXaXp7hrann); the refreshed token is persisted back to auth.json.

Why the web surface is reachable only through a real browser: the consumer backend-api/* paths sit behind Cloudflare bot-detection plus a sentinel proof-of-work (sentinel/chat-requirements + an in-page sentinel/sdk.js that computes the token). A bare bearer-token request is rejected at the edge; only a genuine logged-in browser passes. That's the whole reason the web backend drives a browser instead of calling the endpoint directly.

Related

• HTTP gateway sibling (for multi-app / SDK-compatible usage): https://github.com/leeguooooo/agent-cli-to-api