For AI agents: the documentation index is at /llms.txt, and any docs page is available as Markdown by appending .md to its URL.

Reasoning

Verified

A collapsible 'Thinking' section that opens while the model reasons and folds when it finishes.

The user wants the release notes. I should list the three changes in order, newest first.

When to use

Use when: Showing a model's thinking while it works, then folding it away.
Avoid when: Content the reader must see; put it in the message.

Installation

bunx shelf add reasoning

The source lands in src/components/ui/reasoning.tsx, along with any Shelf items it builds on, and .shelf/lock.json records what was installed. It's yours to edit.

Usage

import * as Reasoning from "@/components/ui/reasoning";

<Reasoning.Root streaming={part.state === "streaming"}>
  <Reasoning.Trigger />
  <Reasoning.Content>{part.text}</Reasoning.Content>
</Reasoning.Root>

Built on

Packages: @stylexjs/stylex
Shelf items: Collapsible, foundations, Icons, Shimmer, utils
Figma: Optional native Figma library. See Designers.

Verified

Size: 1.5 kB gzipped on its own, 12 kB with the Shelf items and packages it builds on. JS and CSS in a production build, without React.
Accessibility: Axe passes on 1 story
Behavior: 1 interaction test in Storybook
Rendering: Parent re-renders skip its consumers
React Compiler: Compiles with React Compiler
React Doctor: React Doctor finds nothing