Play Quick Start

Start the Play UI

From the root of an agent project:

lantern play

From anywhere:

lantern play /path/to/my-agent-project

AgentLantern prints the local Play UI URL. Open that URL in your browser.

By default, the Play UI runs on http://127.0.0.1:7891 and the WebSocket event stream runs on ws://127.0.0.1:7890.

Run the Crew

1. Wait for the UI status to show Ready.
2. Click START.
3. Watch the city, timeline, tools, comms, and log panels.
4. Click STOP if the run is too long or blocked.
5. Click RESTART to launch a fresh run.

The crew does not start automatically unless you pass --name. Without --name, the UI asks for a run name before START.

Custom Ports

Use custom ports when defaults are already taken:

lantern play /path/to/project --ws-port 8790 --http-port 8791

Open:

http://127.0.0.1:8791?ws=8790

The UI also infers the WebSocket port from the HTTP port (8791 -> 8790) when ?ws= is missing.

Save a Run While Starting

lantern play /path/to/project --name demo-run

This saves events to:

.lantern_replays/demo-run.jsonl

It also skips the start overlay and launches automatically.