WebChat (loopback + SSH tunnel)

Updated: 2025-12-09

What it is

A local web UI for chatting with the Gateway.
Static assets served by the WebChat HTTP server (default port 18788, configurable).
The WebChat backend holds a single WebSocket connection to the Gateway (ws://127.0.0.1:18789 by default) for all control/data: history fetch, sends, agent runs, presence.
Trust model: access is granted by being on localhost or inside your SSH/Tailscale tunnel. No additional auth prompts once you can reach the box.
webchat.gatewayPort config can point at a non-default Gateway port if needed.

GET /webchat/info?session=<key> → { port, sessionId, initialMessages, basePath } plus history from the Gateway session store.
GET /webchat/* → static assets.
POST /webchat/rpc → proxies a chat/agent action through the Gateway connection and returns { ok, payloads?, error? }.

On startup, the WebChat server dials the Gateway WebSocket and performs the mandatory hello handshake; the hello-ok snapshot seeds presence + health immediately.
All outgoing sends/agent calls are requests on that WS; streamed events (agent, presence, tick) are forwarded to the browser client.
If a seq gap is detected in Gateway events, WebChat auto-refreshes health + presence and broadcasts a gateway-refresh to connected browsers.
If the Gateway WS is unavailable, WebChat fails fast and surfaces the error in the UI.

SSH tunnel example: ssh -N -L 18788:127.0.0.1:18788 -L 18789:127.0.0.1:18789 user@host.
Browse to http://127.0.0.1:18788/webchat/?session=<key> through the tunnel; the backend WS also rides the tunnel.

webchat.enabled (default true)
webchat.port (default 18788)
Gateway WS port is set by clawdis gateway --port; WebChat expects it at 18789 unless overridden.