21st AI — sketch, iterate & grab code from the terminal 21st AI is a fast UI-drafting board. Mental model: draft it here, then finish it — sketch a few variants from a prompt, preview them, refine the one you like with plain-English edits, and pull its code into the repo. The whole loop runs from the CLI (or the matching MCP tools), so you never leave the editor. Sketch mode produces self-contained HTML + Tailwind drafts (fast, no build). The recommended handoff is the copy-prompt : a spec that tells you to rebuild the design in the target project's real stack — not paste raw HTML verbatim. A…