# Overview & launch

> For the complete documentation index, see [llms.txt](/llms.txt)

The viewer is your home base: browse scenarios, run them, watch each step live,
and debug failures — all locally.

## Launch

```sh
npx @unotest/web viewer
```

It starts a localhost HTTP + WebSocket server and opens your browser. Set
`UNOTEST_VIEWER_NO_OPEN=1` to start without opening a tab. Your agent can also
launch it via the `open_viewer` MCP tool.

## What it is

- **Local-only.** No cloud, no account. It reads run artifacts from
  `unotest/.runs/` and your scenarios/helpers/collections from disk.
- **Read + run.** Browse and run; results stream live over WebSocket.
- **Single source of truth.** Breakpoints and variables are files on disk, so
  the CLI, the agent and the viewer all agree.

## Next

- [Tour](/viewer/tour/) — the activity bar and panels
- [Running tests](/viewer/running/)
- [Step debugger](/viewer/debugger/)