# Reasoning (Lumen Halo): prompt.md (v1.0.0)

- id: `lumen-reasoning` · version 1.0.0 · component · pro (Pro)
- category: AI interfaces
- build: Base UI (one set of files; its dependencies follow the build)
- install (this build): `npx shadcn@latest add @beautiful-ui-pro/lumen-reasoning`
- npm dependencies: none
- registry dependencies: utils, @beautiful-ui/lumen-collapsible, https://beautiful-ui.dev/r/lumen-foundation.json
- docs: https://beautiful-ui.dev/components/lumen-reasoning
- The install command carries everything this item needs (files, CSS, tokens, npm and registry dependencies). Prefer it to copying source by hand.

What a model did before it answered, kept to one quiet line: Thinking with a running clock while it works, its steps open to watch them land, then Thought for 12s with the steps folded away. Each step is waiting, working, done or failed.

## Build it
- Stack: React 19 (`ref` is a plain prop), TypeScript, Tailwind CSS v4 utilities, a shadcn-initialised project with the `@/*` alias.
- Packages: none beyond React.
- Files: `components/ui/lumen/controls/reasoning.tsx`.
- Registry dependencies, installed with it automatically: shadcn `utils` (cn), `lumen-collapsible`, `lumen-foundation`.
- Builds: one set of files for both, but its dependencies come in Base UI and Radix builds. Install the one that matches the project (see Install): a free item's bare URL installs the Base UI build of it and its dependencies.
- Exports to keep: `Reasoning`, and every exported type.
- CSS: the install merges this item's rules (the registry `css` field) into your global stylesheet, in `@layer components`, and adds the lumen foundation (tokens, keyframes, motion levels) once. Nothing to import by hand.
- Re-running `add` (or `--overwrite`) re-applies those rules: put overrides in your own CSS, never in the installed rules.
- Tokens: retheme with the `--lumen-*` custom properties (`--lumen-accent`, `--lumen-accent-foreground`, `--lumen-accent-text`, `--lumen-bad`, `--lumen-bad-text`, `--lumen-chart-accent`, `--lumen-chart-accent-foreground`, `--lumen-chart-accent-text`, `--lumen-focus`, `--lumen-good`, `--lumen-good-text`, `--lumen-hairline`, `--lumen-ink`, `--lumen-muted-ink`, `--lumen-series-1`, `--lumen-series-2`, `--lumen-series-3`, `--lumen-series-4`, `--lumen-series-5`, `--lumen-series-6`, `--lumen-warn`, `--lumen-warn-text`); this item's CSS also reads `--lumen-font-mono`, `--lumen-font-sans`, `--lumen-radius-k`. Never add Tailwind colour classes inside the component.

```tsx
import { Reasoning, type ReasoningStep } from "@/components/ui/lumen/controls/reasoning";
```

## Parts

| Part | data-slot | What it is for |
|---|---|---|
| `Reasoning` | — | The line (reasoning-trigger), the steps (reasoning-content, each reasoning-step with data-status) and the status. |

## Sound
- Keep every `data-slot` and `data-sound` attribute: the sound layer reads them.
- Installing this item adds no audio. Nothing plays until the app mounts `GlassSoundProvider` once (install: `npx shadcn@latest add https://beautiful-ui.dev/r/glass-sound.json`, import from `@/components/beautiful-ui/glass-sound`); `GlassSoundToggle` is its mute control. Without a provider the audio engine never loads.

## Match the original
- Read `components/ui/lumen/controls/reasoning.tsx` as the reference implementation before changing or recreating anything, and match it: sizes, colours per theme, motion timings, copy and behaviour.
- If you deviate (a prop you can't honour, a style you changed, a dependency you swapped), say so in your reply, part by part.
- Keep the accessibility contract, the keyboard map and the motion levels listed below.

## Use it when
- AI reasoning, thinking steps, chain of thought summary, model is thinking indicator, thought for N seconds, Lumen
- Above a model's reply, to show (and hide) what it did first
- Any short multi-step process the reader may want to inspect but not watch

### Not when
- An agent whose steps need approval: use Agent Run
- A plain loading state with no steps: use Spinner or the Message typing mark

## Mistakes
- Don't show raw chain-of-thought you haven't vetted: summarise steps
- Keep step ids stable as statuses change, or each update remounts the list

## Usage

```tsx
"use client";

import { Reasoning, type ReasoningStep } from "@/components/ui/lumen/controls/reasoning";

export function ReplyThinking({ steps, thinking, startedAt }: { steps: ReasoningStep[]; thinking: boolean; startedAt: number }) {
  return <Reasoning steps={steps} thinking={thinking} startedAt={startedAt} />;
}

// Steps as your model reports them:
export const example: ReasoningStep[] = [
  { id: "read", label: "Read the March invoices", detail: "212 invoices, 3 currencies", status: "done" },
  { id: "match", label: "Match payments to invoices", status: "active" },
  { id: "flag", label: "Flag anything unpaid after 30 days", status: "pending" },
];
```

## Props

| Prop | Type | Default | What it does |
|---|---|---|---|
| `steps` | `ReasoningStep[]` |  | { id, label, detail?, status?: pending \| active \| done \| error }. |
| `thinking` | `boolean` | `false` | Still at work: the line reads Thinking, shimmers and runs a clock. |
| `startedAt / duration` | `number (epoch ms) / number (ms)` |  | For the clock and for Thought for …; both are measured here when omitted. |
| `open / defaultOpen / onOpenChange` | `boolean` |  | Uncontrolled: open while thinking, folded when done, unless the reader chose. |
| `children` | `ReactNode` |  | Free-form reasoning text after the steps. |
| `labels` | `Partial<ReasoningLabels>` |  | thinking, thought(duration), done, steps(n), status words: for other languages. |

Full docs: https://beautiful-ui.dev/components/lumen-reasoning

## Customising
- Colours: set the `--lumen-*` tokens on `:root`, or on a container with the `lumen-scope` class to retheme one area. Add the `lumen-inherit` class to follow your shadcn palette instead (`--chart-N`, `--destructive`).
- Dark mode follows the `.dark` class on an ancestor (the shadcn and next-themes convention).
- Update later by re-running the install with `--overwrite` (review the diff if you edited it). Changelog: https://beautiful-ui.dev/r/changelog.json

## Keyboard

| Keys | Action |
|---|---|
| Enter or Space | Open or fold the steps |

## Motion inventory

| Interaction | What moves |
|---|---|
| Thinking | The line and the working step shimmer; reduced motion holds them still |
| Open and fold | The panel eases open with Collapsible's timing; the chevron turns |

## Accessibility contract (preserve when editing)
- The line is a disclosure button (aria-expanded) over the steps
- A polite status says Thinking, then Thought for …, once each, not every second
- Each step's status is read after its label; the working step is aria-current

## Install

```bash
npx shadcn@latest add @beautiful-ui-pro/lumen-reasoning
```

Pro item: needs the `@beautiful-ui-pro` registry in `components.json` and `BEAUTIFUL_UI_TOKEN` in `.env.local` (https://beautiful-ui.dev/account). Setup: https://beautiful-ui.dev/docs/pro. Your components.json `style` picks the build: radix-*, new-york and default get Radix, base-* gets Base UI.

## Credits
- Built on shadcn/ui (https://ui.shadcn.com)

The lumen foundation (the tokens listed above, keyframes and motion levels) installs once with the first component; its CSS is public at https://beautiful-ui.dev/r/lumen-foundation.json.