# Border Trace Button

> The outline is the loader: while the action runs, a glowing gradient comet laps the pill's border, then a green stroke draws the ring closed on success (red, with a shake, on failure). The perimeter is measured, so any width works.

- Slug: `border-trace-button`
- Category: [Buttons](https://www.assembli.design/category/buttons.md)
- Type: component
- Tags: loader, border, outline, async, gradient
- npm dependencies: none
- shadcn/ui dependencies: none
- Added: 2026-10-24
- Live preview: https://www.assembli.design/preview/border-trace-button
- Page: https://www.assembli.design/components/border-trace-button

## Install

One-time setup (needs a subscription):

1. Add the registry to the project's `components.json`: `{"@assembli":{"url":"https://www.assembli.design/r/{name}.json","headers":{"Authorization":"Bearer ${ASSEMBLI_API_KEY}"}}}` (merge into `"registries"`).
2. Put an API key from https://www.assembli.design/account in `.env.local` as `ASSEMBLI_API_KEY=asm_…`.

Then install with the shadcn CLI (writes `components/border-trace-button/border-trace-button.tsx` and installs dependencies):

```bash
npx shadcn@latest add @assembli/border-trace-button
```

Registry item JSON: https://www.assembli.design/r/border-trace-button.json (send `Authorization: Bearer <api key>`)

## Code

> Component source needs an Assembli subscription ($12/month) and an API key sent as `Authorization: Bearer <key>`. To get one without copying anything, POST https://www.assembli.design/api/agent/login (or call the MCP tool connect_account), show the user the link it returns, and poll https://www.assembli.design/api/agent/token for the key. Or subscribe at https://www.assembli.design/pricing and create a key at https://www.assembli.design/account.