Prototype script sends 3 design briefs to OpenAI Responses API with
image_generation tool. Results: dashboard (47s, 2.1MB), landing page
(42s, 1.3MB), settings page (37s, 1.3MB) all produce real, implementable
UI mockups with accurate text rendering and clean layouts.
Key finding: Codex OAuth tokens lack image generation scopes. Direct
API key (sk-proj-*) required, stored in ~/.gstack/openai.json.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Garry Tan