openui

SKILL.md

OpenUI — The Open Standard for Generative UI

OpenUI is a full-stack Generative UI framework by Thesys. At its center is OpenUI Lang: a compact, line-oriented language designed for LLMs to generate user interfaces, up to 67% more token-efficient than JSON-based alternatives.

Instead of treating LLM output as only text/markdown, OpenUI lets you define a component library, auto-generate a system prompt from it, and render structured UI progressively as the model streams.

Core Architecture

OpenUI has four building blocks that form a pipeline:

Library — Components defined with Zod schemas + React renderers via defineComponent. This is the contract between app and AI: it constrains what the LLM can generate.

Prompt Generator — library.prompt() converts the library into a system prompt with syntax rules, component signatures, and streaming guidelines.

Parser — Parses OpenUI Lang line-by-line (streaming-compatible) into a typed element tree. Validates against the library's JSON Schema.

Renderer — The <Renderer /> React component maps parsed elements to your React components, rendering progressively as the stream arrives.

Component Library → System Prompt → LLM → OpenUI Lang Stream → Parser → Renderer → Live UI