Define the structural layer of a product or site before visual design begins. Covers navigation, content hierarchy, page structure, URL patterns, and user flows. Use when user wants to plan site structure, define navigation, map user flows, organize content, or mentions "IA" or "information architecture".

Fast headless browser for QA testing and site dogfooding. Navigate any URL, interact with elements, verify page state, diff before/after actions, take annotated screenshots, check responsive layouts, test forms and uploads, handle dialogs, and assert element states. ~100ms per command. Use when you need to test a feature, verify a deployment, dogfood a user flow, or file a bug with evidence. gstack also includes development workflow skills. When you notice the user is at these stages, suggest th