Playground builds HTML prompt explorers

Playground feels like a small plugin with outsized leverage: it converts prompt engineering from guess-and-refresh into something closer to a proper interface builder.

• –It ships as a single-file HTML output with inline CSS and JavaScript, so the artifact is portable, inspectable, and easy to share
• –The live preview plus human-readable prompt output makes it useful as a bridge between experimentation and production implementation
• –Anthropic positions it for multiple workflow types, including design playgrounds, data explorers, concept maps, and document critique flows
• –Third-party writeups are already framing it as a way to cut down on repetitive Claude Code design loops, which is a strong signal it solves a real workflow pain point