Skip to main content

​
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: 
handler tui
You can also open servers automatically on startup. Open a configured server by name: 
handler tui --server demo
Open multiple configured servers in tabs: 
handler tui --server demo --server staging
Open a server by URL without saving it first: 
handler tui --url http://localhost:8000
Override auth with a bearer token from the environment: 
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
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 and 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: 
handler web

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.