Skip to main content
@craft-ts
Beta

Live page MCP#

The running development tab publishes its named controls. A coding agent fills, clicks, and inspects that page — no second browser, no DOM reverse-engineering.

Use it when a Cursor agent must drive or inspect the ng serve tab you already have open. Not when you are writing Craft away from a running app — use @craft-ts/mcp for docs and skills. Not when you want to mutate a primitive without the UI — use the registry.* tools on the same local MCP.

Connect the local MCP#

The tool lives on @craft-ts/function-registry-mcp, not on the published @craft-ts/mcp docs server. From the craft-ts repo:

sh
npm run registry:mcp

Point Cursor at that stdio server. It already listens on ws://127.0.0.1:3333 for the demo tab. Each tab keeps a stable clientId in sessionStorage.

One ready tab#

Each tab has a clientId in sessionStorage. Duplicating a tab copies it; the broker assigns a new id (hello/ok) so the two tabs do not fight.

Omit clientId when exactly one tab is ready. A ghost reloading card (HMR, F5) does not count. Two ready tabs → pass clientId from registry.clients (id, status, url). Never pick “latest”. The error is Multiple ready page clients; clientId is required. Available clients: <id> ready <url>, <id> ready <url>. Zero ready with several ghosts is No ready page client. Reloading: <id> (last url <url>), <id> (last url <url>). Zero cards is page client is not connected.

Closing the tab sends page/goodbye; the card is dropped. Opening a new tab is a new id. If page client "<id>" is not connected, call registry.clients and retry without id when a single ready remains.

Closing without goodbye (crash) looks like reload for up to 20s.

One tool: page#

Omit act to read the current surface. The broker always asks the live tab — a Craft value: that changed without a DOM mutation is still current. Pass act to run a batch, then receive the new state in the same round-trip.

Default detail is "controls": the named interactive surface (id, role, accessible name, value, enabled, index, and track when the node is inside forNode). Pass detail: "dom-styles" only to debug layout or CSS — it is large and opt-in.

id is the literal local name from the helper:

ts
import { button, craftComponent } from '@craft-ts/component';

const SaveToolbar = craftComponent(
  'SaveToolbar',
  {},
  () => button('save', { type: 'button' }, 'Save'),
);

That name is unique in the app graph (assertInteractiveElementNamed). The renderer writes data-craft-name="save". Do not prefix it with the component name. When forNode repeats the same id, pass match.index or match.track.

Fill, click, goto, ready#

act: [{ "goto": "/login-form" }] navigates in the tab (Craft router). The WebSocket stays up. Prefer goto over clicking navLink — every nav item shares that id. Paths like /login-form and full URLs both work.

A fill sets the control and dispatches one input or change (then blur), so CraftFieldDirective validation and touched state run. A click is act with only id. The batch runs in order and stops on the first error.

While ng serve rebuilds, the socket drops but the broker keeps the client card. page waits until the tab is ready again (up to timeoutMs, default 20s). You do not poll.

See also#

Search