# Mention Composer (Lumen Halo): prompt.md (v1.0.0)

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

Write a note and mention people by typing @: suggestions open at the caret and narrow as you type, and a picked name becomes a mention that's highlighted, deleted as a whole and kept with its id. A real textarea underneath, so editing, spellcheck and undo stay native.

## 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/mention-composer.tsx`.
- Registry dependencies, installed with it automatically: shadcn `utils` (cn), `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: `MentionComposer`, 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-sans`, `--lumen-radius-k`. Never add Tailwind colour classes inside the component.

```tsx
import { MentionComposer, type MentionValue } from "@/components/ui/lumen/controls/mention-composer";
```

## Parts

| Part | data-slot | What it is for |
|---|---|---|
| `MentionComposer` | — | The field, its highlight layer and the suggestions. |

## 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/mention-composer.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
- mention input, @mention, comment box, tag a teammate, notify people, rich comment, Lumen
- Comments, notes and messages where people tag teammates (or tickets, docs, anything with an id)

### Not when
- Rich formatting (bold, lists): use an editor framework
- Choosing people without writing text: use Combobox

## Mistakes
- Store the mentions' ids, not the display names (people rename)
- Keep suggestions short (we show 8)

## Usage

```tsx
"use client";

import * as React from "react";
import { MentionComposer, type MentionValue } from "@/components/ui/lumen/controls/mention-composer";

const team = [
  { id: "u1", label: "Maya Chen", description: "Design" },
  { id: "u2", label: "Tomás Ruiz", description: "Data" },
];

export function Comment() {
  const [note, setNote] = React.useState<MentionValue>({ text: "", mentions: [] });
  return <MentionComposer value={note} onValueChange={setNote} suggestions={team} placeholder="Write a comment, @ to mention" />;
}
```

## Props

| Prop | Type | Default | What it does |
|---|---|---|---|
| `suggestions` | `MentionEntity[] \| (query, signal) => Promise<MentionEntity[]>` |  | Who can be mentioned ({ id, label, description? }): a list filtered as you type, or your search (abort on the signal). |
| `value / defaultValue / onValueChange` | `{ text, mentions: { id, label, start, end }[] }` |  | The text and the mentions with their ids and positions. mentionSegments(value) gives ordered segments. |
| `onSubmit` | `(value) => void` |  | ⌘ / Ctrl + Enter. |
| `trigger` | `string` | `"@"` | The character that starts a mention. |
| `rows / placeholder / disabled` | `textarea props` | `3` | As on a textarea. |
| `labels` | `object` |  | suggestions, noMatch and count(n), for other languages. |

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

## 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 |
|---|---|
| @ | Start a mention |
| Arrow up / down, Enter or Tab | Pick a suggestion |
| Escape | Close the suggestions |
| Backspace into a mention | Remove the whole mention |
| ⌘ / Ctrl + Enter | onSubmit |

## Motion inventory

| Interaction | What moves |
|---|---|
| Suggestions | Open at the caret with a short drop |
| Mention | The new mention glows once, then settles |

## Accessibility contract (preserve when editing)
- A native textarea with aria-autocomplete=list pointing at the suggestions (aria-activedescendant), not a re-roled textbox
- The number of suggestions is announced; Escape closes them without leaving the field

## Install

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

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.