canvas
canvas

CLI

.md

canvas serve, its options and environment.

Terminal window
canvas serve [--dir .] [--port 4418] [--web-url URL] [--tls-host NAME] [--cert FILE] [--key FILE]

Starts canvas serve for a project and prints the host link. Run it with bunx @frebreco/canvas serve, or install @frebreco/canvas and run canvas serve.

Options

Option Default Effect
--dir . The project directory: agents, terminals and files work here
--port 4418 The port canvas serve listens on
--web-url https://ui.canvas.frebreco.de, or …/next for a pre-release The web app the host link opens
--tls-host none Serve wss:// on this host name, on all interfaces
--cert, --key .certs/dev.crt, .certs/dev.key in canvas’s own directory The certificate for --tls-host

Environment

Variable Effect
CANVAS_WEB_URL Default for --web-url
CANVAS_OPENCODE_MODEL opencode’s model for new sessions (default opencode-go/big-pickle)

Hosting from another device

By default canvas serve listens on 127.0.0.1, so the host’s browser must run on the same machine. To be the host from another device, for example over a Tailscale network, serve TLS on a name that device can reach:

Terminal window
tailscale cert --cert-file cert.crt --key-file cert.key machine.tailnet.ts.net
canvas serve --tls-host machine.tailnet.ts.net --cert cert.crt --key cert.key

canvas serve then listens on all interfaces. Anyone who can reach the port still needs the token.

Output

canvas serving /home/you/src/shop


  open the board as host:
  https://ui.canvas.frebreco.de/?room=…#k=…&pk=…&server=ws%3A%2F%2F127.0.0.1%3A4418&token=…

The link is the same on every start in the same directory, as long as .canvas/room.json exists.