feat(a11y): Implement AccessKit accessibility support for all UI components

[huacnlee]

Summary

• Adds Role, aria_* attributes, and on_a11y_action handlers to all major UI components using the AccessKit integration in the latest GPUI
• Covers interactive controls, navigation, overlays, data display, containers, and form components (~25 component files)
• Adds Root component Role::Application landmark so the accessibility tree has a proper application root below Window
• Adds script/run-story-macos helper to build and launch Story gallery as a signed macOS .app bundle for VoiceOver testing

Component role mapping

Component	Role	Extra attributes
Button	Button / Link	aria_label, aria_selected
Toggle / ToggleGroup	Button + aria_toggled, Toolbar	—
Checkbox	CheckBox	aria_toggled, aria_label
Radio / RadioGroup	RadioButton, RadioGroup	aria_selected, position_in_set, size_of_set
Input	TextInput / MultilineTextInput	—
NumberInput	SpinButton	aria_numeric_value
Slider	Slider	aria_numeric_value, min/max, aria_orientation, Increment/Decrement a11y actions
Tab / TabBar	Tab + aria_selected, TabList	—
PopupMenu / AppMenuBar	Menu, MenuBar	—
MenuItem	MenuItem	aria_selected
Dialog / AlertDialog	Dialog (configurable), AlertDialog	—
Alert	Alert	—
Progress	ProgressIndicator	aria_numeric_value, min/max
List / ListItem	List, ListItem	aria_position_in_set, aria_size_of_set, aria_selected
Table / Header / Body / Row / Cell	Table, RowGroup, Row, ColumnHeader, Cell	aria_row_index, aria_column_index
Accordion / item header	Group, Button + aria_expanded	—
GroupBox	Group	—
Combobox	ComboBox	aria_expanded
DropdownButton	Group	—
Stepper / StepperItem	Group, ListItem	aria_position_in_set
BreadcrumbItem	Link / ListItem	—
FormField	Group	—
Root	Application	—

Verification guide

Prerequisites

AccessKit only builds the full accessibility tree when an assistive technology is active. Accessibility Inspector alone is not sufficient — you must enable VoiceOver first.

macOS — VoiceOver + Accessibility Inspector

# 1. Build and launch Story gallery as a signed .app bundle
./script/run-story-macos

# 2. Enable VoiceOver  (this activates AccessKit)
Cmd + F5

# 3. Open Accessibility Inspector
#    Xcode → Xcode menu → Open Developer Tool → Accessibility Inspector
#    (or: open -a "Accessibility Inspector")

# 4. In Accessibility Inspector, click the target crosshair icon,
#    then hover over or click elements in the Story window.
#    You should see the full hierarchy:
#    Application > Window > Application > Button / CheckBox / Tab / ...

# 5. Tab through interactive elements — VoiceOver announces each one.

# 6. Test Slider keyboard control:
#    Focus the Slider, then press Up/Down arrows (Increment/Decrement a11y actions).

Key things to verify

• Button: role AXButton, label matches button text
• Checkbox: role AXCheckBox, value changes on click
• Toggle: role AXButton, AXValue reflects checked state
• Radio group: each item reports AXPositionInSet / AXSizeOfSet
• Tab bar: AXTabGroup containing AXTab items, selected tab has AXValue = 1
• Dialog: role AXDialog when open, focus trapped inside
• Slider: AXSlider with AXMinValue / AXMaxValue / AXValue, responds to VoiceOver Increment/Decrement

Windows — NVDA

cargo run
# Enable NVDA, Tab through the window.
# NVDA should announce component type and label on focus.

Linux — AT-SPI (Orca)

cargo run
# Enable Orca, Tab through the window.

---

Note: active_flag starts false and becomes true only on first AT query.
If Inspector shows only Window with no children, ensure VoiceOver is on,
then wait ~1 second and click Refresh in Accessibility Inspector.

🤖 Generated with Claude Code

[grishy]

Great thx for your work!
One thing I think before merging: Button better to expose an explicit aria_label(...) override, especially for icon-only buttons.

like:

Button::new("close")
    .icon(IconName::X)
    .aria_label("Close")

[huacnlee]

Still not working, I don't know the reason. macOS Accessibility inspector can't select any elements.

[grishy]

I think this is because it is not perfect in GPUI itself. I wrote a small Swift wrapper for tests myself.

It needs two actions:

1. First ask AX on the app. It will switch GPUI into Access ON mode, return only the root object, and call update on the whole tree.
2. Second ask AX on the app again. Now we have the proper AX tree of the app.

So, on the first try, it only activates the AX tree (GPUI here is lazy), but it returns the wrong tree initially. It should wait until all components are updated and only after that return to AX's caller.

If it will work fine for me, I will create a PR here 👍