imagegen

imagegen

一句话定位：借 Codex agent 内置的图像生成能力出图；本 Skill 只管五件事——把需求翻成好提示词、把命令跑通、验收、压缩、放进项目该在的目录。

图像生成不是 CLI 子命令（没有 codex image；codex exec --image 是把图当输入附上）。它是 Codex agent 的内置工具 image_gen。不要翻 codex --help 找 flag，找不到就下结论"不能生图"——这个结论是错的。描述你要的图，让 agent 自己选方法。

启动命令

mkdir -p <outdir>                                # 先建目录，提示词里写它的绝对路径
cat <outdir>/prompt.md | codex exec --skip-git-repo-check \
  --config model_reasoning_effort="medium" \
  --sandbox danger-full-access \
  -C <outdir> -o <outdir>/final.md 2>/dev/null

codex --version 失败或启动就退出：先 codex doctor，如实报告，不要盲目重试。

提示词怎么写

一份 prompt.md 必含六样，缺一样就会出一类问题：

1. 输出目录绝对路径（已 mkdir -p）。
2. 逐张编号：精确文件名 + 具体描述 + 像素尺寸/比例。
3. 共享风格块：画风、背景、hex 调色板、光线、镜头——一套图靠它保持一致。
4. No text, no letters, no logos, no watermarks. 生成的字几乎必花，非英文界面更是错字；文字后期用 HTML/CSS 叠。
5. 逃生口：If you genuinely cannot generate images, say so plainly. Do not substitute placeholders, ASCII art, solid rectangles, or images downloaded from the web.
6. 回报要求：每个文件的绝对路径、实际像素、字节数、有无 alpha、所用方法（哪个工具/模型、有无本地后处理）。

透明图务必写 true alpha, not a white/dark square——实测 Codex 靠这句自检，第一版烤了底色又自己返工。

再加一条常用兜底：If the exact size is unsupported, generate the nearest aspect and resize locally (sips / PIL) to the exact pixels; keep alpha for transparent items.

完整示例（吉祥物 + og:image 两张一套）

Generate two images with your built-in image generation tool and save them to:
<outdir absolute path>/

Shared style: palette #2563EB (primary) #F59E0B (accent) #0F172A (ink) #F8FAFC (paper).
No text, no letters, no logos, no watermarks anywhere.

1. `mascot-logo.png` — 1024x1024, transparent background PNG (true alpha, not a white square).
   A friendly round owl holding a tiny wrench. Flat vector style, bold clean shapes,
   2-3 flat tones per element, no gradients, no drop shadows. Occupies 75-80% of the
   frame, centered, props included in that measure.

2. `og-image.png` — 1200x630 (1.91:1), opaque. Photorealistic editorial photo: a person
   in their late twenties at a wooden desk in front of a laptop, soft window light from
   the left, shallow depth of field, calm home office, mug and small plant. Eye-level,
   subject on the left so the right third is clean negative space. Laptop screen is a
   soft blurred blue-white glow, nothing readable.

Rules: if you genuinely cannot generate images, say so plainly — no placeholders, ASCII
art, solid rectangles, or web downloads. If the exact size is unsupported, generate the
nearest aspect and resize locally (sips / PIL); keep alpha for the mascot.
Report per file: absolute path, actual pixels, bytes, alpha yes/no, method used.