UI Events

These events fire when Claude Code draws part of the interface, and when a person uses a control that a mod drew. The second table lists the events that the $.ui methods raise.

A deny from a hook refuses a scroll, focus, or close. An invalid tree draws the engine's own drawing.

Official pages: Draw in the Interface, Mods Reference. Source: the program (types-2.1.304.d.ts).

Example

This hook adds a count to the spinner.

let calls = 0
on('tool.call', ($, e, next) => { calls += 1; return next(e) })
on('ui.render', { component: 'Spinner' }, async ($, e, next) =>
  next({ ...e, props: { ...e.props, suffix: ' · tool calls: ' + calls + '…' } }))

Engine Events

Item	Status	What it does	How it works	Where it can be used
`ui.render`	Documented	Fires when the engine is about to draw a component: once for each input value (props, viewport width), at plugin load, or on `$.ui.invalidate("ui.render")`.	Input `RenderInput`. Result `RenderElement`: the tree to draw. `next(e)` gives the engine's drawing. An invalid tree draws the engine's drawing.	`on('ui.render', ...)`. In tests: `$.ui.render(...)` on the test engine (not on a hook's `$`).
`ui.resolve`	Documented	Fires when the plugins load (not on each draw), once for each surface, component, and plugin. `e` names the surface and component, never the props.	Input `ResolveInput`. Result `ElementTable`: the element table of the surface. A hook may restyle an element or leave one out.	`on('ui.resolve', ...)`. Also `$.ui.resolve(...)`.
`ui.press`	Documented	Fires when a `Button` that a render hook drew is pressed on a surface. `e` is `{ plugin, element, component, surface }`. `element` is the button's `key`. Set a `key` on buttons that share a label: until 2.1.304 a click was lost when same-label buttons with no `key` were redrawn unchanged.	Input `UiPressArgument`. Result `{ element }`. `next(e)` lets the press through. Returning `{ element }` takes it.	`on('ui.press', ...)`.
`ui.input`	Documented	Fires when an `Input` that a render hook drew changes or is submitted. `e` is `{ plugin, element, component, surface, kind, value }`.	Input `UiInputArgument`. Result `{ element, value }`. `next({ ...e, value })` rewrites the typing.	`on('ui.input', ...)`.
`ui.select`	Documented	Fires when a `Select` that a render hook drew is picked from. `e` is `{ plugin, element, component, surface, value }`.	Input `UiSelectArgument`. Result `{ element, value }`. `next({ ...e, value })` rewrites the pick.	`on('ui.select', ...)`.
`ui.message`	Documented	Fires when a `Client` that this plugin drew posts from its surface module (`surface.post(data)`). Only this plugin's hooks see it.	Input `UiMessageArgument`. Result `{ props? }`. `next({ ...e, data })` rewrites the data. One call for each instance in each frame.	`on('ui.message', ...)`.
`ui.fault`	Documented	Fires when a `Client` that this plugin drew failed on a surface: its module did not load, its drawing failed, or its code failed after it drew.	Input `UiFaultInput`. Result `{}`. Only this plugin's hooks see it. `e.phase` says when and `e.reason` says why.	`on('ui.fault', ...)`.
`ui.scroll`	Documented	Fires before the window of a site moves: the person's wheel or scroll keys on a `Pane` body or the `AbovePrompt` band (at its edges too), or `$.ui.scroll`.	Input `UiScrollInput`. Result `{}` or `{ deny }`. `next({ ...e, offset })` scrolls elsewhere.	`on('ui.scroll', ...)`. Also `$.ui.scroll(...)`.
`ui.focus`	Documented	Fires before the focus ring of a site moves: the person's Tab, arrows, or click in a `Pane` or the band, an `autoFocus` element taking it, or `$.ui.focus`.	Input `UiFocusInput`. Result `{}` or `{ deny }`. `next({ ...e, element })` moves the focus to another element.	`on('ui.focus', ...)`. Also `$.ui.focus(...)`.

Events Raised by UI Calls

For each call, a hook above the caller returns next(e), { deny: reason }, or { value }.

Item	Status	The argument	Input and value
`ui.toast`	Documented	`$.ui.toast(text, { timeoutMs })`	Input `{ text: string, timeoutMs?: number }`. Value `void`.
`ui.status`	Documented	`$.ui.status(text)`. `text` undefined clears the line.	Input `{ text: string \| undefined }`. Value `void`.
`ui.log`	Documented	`$.ui.log(text, { to })`. `to` is always present. `next({ ...e, to: "debug" })` keeps a line off screen.	Input `{ text: string, to: UiLogSink }`. Value `void`.
`ui.notice`	Documented	`$.ui.notice(tool_use_id, text)`	Input `{ tool_use_id: string, text: string \| undefined }`. Value `void`.
`ui.invalidate`	Documented	`$.ui.invalidate(event)`	Input `{ event: InvalidatableEventName }`. Value `void`.
`ui.open`	Documented	`$.ui.open({ id, title, focus })`. A hook above may retitle it or refuse with `{ deny }`, never rename it.	Input `PaneOpenArgs`. Value `UiOpenResult`.
`ui.close`	Documented	`$.ui.close({ id })` with `origin` `plugin`. The engine raises it too, for the person (`person`) and for an unload (`unload`).	Input `PaneCloseInput`. Value `void`.
`ui.panes`	Documented	`$.ui.panes()`	Input `NoArgs`. Value `readonly UiPane[]`.
`ui.selection`	Documented	`$.ui.selection()`	Input `NoArgs`. Value `UiSelection \| undefined`.
`ui.copy`	Documented	`$.ui.copy({ text, surface })`. `surface` takes the session's first surface when left out.	Input `UiCopyArgs`. Value `UiCopyResult`.
`ui.view`	Documented	`$.ui.view({ agentId })`: whose transcript the main view shows. None means the main conversation.	Input `SiteView`. Value `UiViewResult`.
`ui.notify`	Documented	`$.ui.notify(text, { title })`. `title` is the plugin's name when left out. Two mods that notify again on hearing a notification can echo each other without end.	Input `{ text: string, title?: string }`. Value `UiNotifyResult`.
`ui.blit`	Documented	`$.ui.blit(...)`: the `cells` of a `Raster` or the `source` of a keyed `Image`. A hook above may rewrite either, or `{ deny }`.	Input `UiBlitArgs`. Value `UiBlitResult`.

Example​

Engine Events​

Events Raised by UI Calls​

Related Pages​

Example

Engine Events

Events Raised by UI Calls

Related Pages