Architecture

Lasso separates the browser experience from source-code access. The browser overlay handles selection and interaction; a local bridge handles filesystem-aware operations.

The request path

Browser overlay → local WebSocket bridge → source context
Browser overlay → API / realtime service → hosted features

The bridge runs on loopback and receives the context needed for the current task. Local CLI agents run on the developer's machine. Hosted model calls go to ai-server; the control-plane API in server handles identity, provider access, billing, and quota. File changes stream back to the overlay for review.

Live page context

Every request carries what the browser is actually doing:

• Route, title, viewport, and a DOM summary of headings, sections, buttons, links, and inputs
• A screenshot of the current view
• The selected element and its source hint (select mode)
• Console and runtime errors — uncaught errors, unhandled rejections, and console.error output captured from page load, attached as context.runtimeErrors (select mode) or pageContext.runtimeErrors (one-shot)

The error buffer resets when a change is applied, so the agent always sees the health of the code that is running now.

Local Host

Lasso Host provides stable .lasso domains and proxies project traffic. HTTP uses 6766; HTTPS uses 6767. WebSocket and HMR traffic are forwarded to the project runtime.

Security boundaries

• Credentials live in the local Lasso directory.
• Filesystem changes require an explicit apply action.
• The host listens on loopback by default.
• HTTPS local domains enable browser capabilities such as microphone access.

Next steps

Start with the quickstart or browse the CLI reference.