Focus

Snapshot the Compose focus state of a preview and drive directional focus traversal (Up, Down, Left, Right, Next, Previous) so agents can verify keyboard / D-pad navigation without an emulator.

At a glance


Kind	`compose/focus`
Schema version	1
Modules	`:data-focus-core` (published) · `:data-focus-connector`
Render mode	default
Cost	low
Token usage	Inline JSON, not yet benchmarked. See token usage.
Transport	inline
Platforms	Android · Desktop · Wear · shared

What it answers

Which node holds focus right now? What testTag, role, label?
After a directional moveFocus(FocusDirection.Down), where does focus land?
Is there a focus trap, dead end, or unexpected wrap?
Does the focus ring overlay match the focusable bounds the developer expects?

The connector ships a FocusController that drives Compose’s FocusManager and a FocusOverlay that renders the focused-node bounding box on top of the captured PNG.

What it does NOT answer

It does not test physical input devices (rotary, gamepad, IME hardware) — it operates on the abstract FocusDirection enum.
It does not score focus order against a designer-defined intent — it reports what the framework chose; reading whether that’s right is on the reviewer.

Use cases

TV / Wear traversal: render every Up/Down/Left/Right step from a known starting node and confirm the path lands on the intended target.
Dialog focus restoration: verify focus comes back to the trigger button after a dialog dismisses.
Form regression: catch a refactor that accidentally makes a TextField non-focusable.

Payload shape

Material3FocusProduct.KIND / FocusOverride and FocusDirection in :data-focus-core and daemon:core.

// compose/focus
{
  "focused": {
    "testTag": "submit-button",
    "role": "Button",
    "label": "Submit",
    "boundsInScreen": "48,200,144,232"
  },
  "history": [
    { "direction": "Down", "from": "name-field", "to": "submit-button" }
  ]
}

Enabling

Pass an override on renderNow.overrides.focus (MCP) to drive traversal, or enable the extension and read focused-node snapshots on every render.

Companion products

UIAutomator hierarchy — uia/hierarchy for the broader set of selector-shaped nodes a click / scroll / type could target.
Layout inspector — compose/semantics for testTag / role / mergeMode of the focused node.