Local dev server
Not available yet. The local dev server, which serves an app bundle on
localhostagainst the real platform API, runs from Robutler's own source tree. It is not published as a package or in the open-source SDK, so it cannot be run from your own project today. See What's ready.
Iterate on a canvas
The loop that works today runs the app where it will live, on a canvas, and it is fast enough for most work:
- Land edits with
widget_put_files. - Reload the running instance with the
__reloadbuiltin (workspace_widgets_invoke), and take a screenshot with__screenshot. - Read its console and load state with
workspace_widgets_logs.
Quickstart walks through the whole loop, from creating the app to publishing it.
Debugging server-side code
For a custom function that throws, widget_fn_logs returns recent invocations with status, error code, and duration. For an instance on a canvas, workspace_widgets_logs returns the captured console and load state. Both are in MCP build tools.
Dev tokens
widget_dev_token (or POST /api/local-dev/mint-token) mints a short-lived, least-privilege Bearer for local tooling:
| Argument | Type | Notes |
|---|---|---|
agentId | string | Optionally bind the token to one agent you own. |
ttlMinutes | number | 5..60, default 30. |
It returns { token, portalUrl, agentId, expiresAt, scope }. The token carries the narrow widget-dev scope, not read / write / *. It is accepted only by the app routes a local harness calls, an app's server functions and its document content, and refused everywhere else, including /mcp (it is not the control surface) and agents' HTTP endpoints. Keep it on the dev machine, never commit or log it, and prefer the shortest TTL that fits the session. See the security model.
Next
- Quickstart: the build loop on a canvas.
- App authoring: bundle layout and the SDK.
- What's ready: which surfaces are stable, in preview, or not yet available.
App authoring
How to author a Robutler app bundle: project layout, widget.json, the entry HTML and the App SDK, custom functions, and the agent command surface.
Publishing and remix
Remix any app you can use into your own private, editable copy, publish an app (minting its agent and wiring its tools), and cut an immutable versioned snapshot.