> ## Documentation Index
> Fetch the complete documentation index at: https://handler.alduncanson.com/llms.txt
> Use this file to discover all available pages before exploring further.

# TUI and web UI

> Use Handler's interactive terminal interface to connect to A2A servers, manage auth, inspect cards, and send messages.

# Use the interactive UI

The TUI is the fastest way to explore an A2A agent when you want a live,
interactive workflow instead of one command at a time.

## Start the TUI

Open the interactive terminal UI:

```bash theme={null}
handler tui
```

You can also open servers automatically on startup.

Open a configured server by name:

```bash theme={null}
handler tui --server demo
```

Open multiple configured servers in tabs:

```bash theme={null}
handler tui --server demo --server staging
```

Open a server by URL without saving it first:

```bash theme={null}
handler tui --url http://localhost:8000
```

Override auth with a bearer token from the environment:

```bash theme={null}
handler tui --bearer-env HANDLER_TOKEN
```

## What you can do with the TUI

* switching between multiple A2A servers in tabs
* inspecting agent cards and supported capabilities
* sending messages and inspecting task responses
* editing auth, custom headers, and server details interactively
* keeping recent sessions close at hand while testing agents repeatedly
* viewing logs without leaving the interface

## Footer shortcuts

The footer shows the shortcuts that are always worth keeping close:

* `Ctrl+P` opens the command palette
* `Ctrl+Q` quits the application
* `?` opens the keybindings panel

## Connecting with configured servers

If you already defined servers in `servers.toml`, the TUI can open them
directly from the picker or from the command line with `--server`.

This is usually the easiest way to work with mTLS or OAuth2 because the server
definition already knows the URL and auth shape. See [Servers](./servers) and
[Authentication](./authentication).

## Auth in the UI

The auth panel supports the same major flows as the CLI:

* bearer tokens
* API keys
* custom headers
* mTLS certificate paths
* OAuth2 client credentials

That makes the TUI useful for debugging an agent before you save the same setup
as server configuration.

## Browser-hosted mode

If you want the same interface in a browser tab, serve it as a web app:

```bash theme={null}
handler web
```

```bash theme={null}
handler web --port 9000
```

By default this binds to `localhost:8001`.

## When to use the CLI instead

Prefer the CLI when you want scripting, optional structured output, shell
history, or repeatable task automation. See
[Messages, tasks, and sessions](./messages-tasks).