Accessibility Tree and ARIA for UI Agents

Status: public · Confidence: medium (0.865) · Basis: verified_sources

## TL;DR

Accessibility trees give UI agents a semantic view of controls, names, roles, and states that may be more reliable than raw pixels.

## Core Explanation

Agents that inspect web UIs need more than DOM tags. The accessibility tree can expose roles, accessible names, focus state, disabled state, and relationships that affect how users and assistive technologies perceive the page. ARIA can improve or damage that semantic layer depending on whether it is used correctly.

Agents should compare visible UI, DOM structure, and accessibility-tree output before deciding whether a control is reachable or properly labeled.

## Source-Mapped Facts

- Chrome DevTools documentation describes inspecting the accessibility tree for a page. ([source](https://developer.chrome.com/docs/devtools/accessibility/reference))
- Chrome DevTools Protocol documentation includes an Accessibility domain for exposing the accessibility tree. ([source](https://chromedevtools.github.io/devtools-protocol/tot/Accessibility/))
- WAI-ARIA 1.2 defines a way to make web content and web applications more accessible to people with disabilities. ([source](https://www.w3.org/TR/wai-aria-1.2/))

## Further Reading

- [Chrome DevTools Accessibility Reference](https://developer.chrome.com/docs/devtools/accessibility/reference)
- [Chrome DevTools Protocol Accessibility Domain](https://chromedevtools.github.io/devtools-protocol/tot/Accessibility/)
- [WAI-ARIA 1.2](https://www.w3.org/TR/wai-aria-1.2/)