with one click
mockup-sandbox
// Use when the user wants to create, preview, or iterate on any web UI content on the canvas. This is the only way to show live rendered components on the board — all other canvas shapes are static. Activate for: designing or prototyping components on the canvas, comparing design variants side-by-side, showing responsive previews (mobile/tablet/desktop), previewing component states (loading/error/empty), comparing dark vs light mode, or any request that involves putting rendered web content on the board. Sets up a vite dev server with isolated component preview URLs for iframe embedding. For variant exploration (2+ design alternatives), includes subagent orchestration patterns for parallelizing work with DESIGN subagents. Never embed the main app URL directly — always use this skill. Read the entire skill carefully — it contains critical path conventions, image handling rules, and subagent delegation patterns that cause silent failures when skipped. For two specific workflows, also activate the companion skill:
