Accessibility Is All You Need – Why agent protocols for the web are redundant

Every few months someone proposes a new standard so AI agents can interact with websites. WebMCP, llms.txt, agent metadata layers.

The accessibility tree already solves this. Labels, roles, states, actions, input formats, validation feedback, it's all there. A screen reader user and an AI agent need the exact same information. If your site works for one, it works for the other.

If you find something an agent can't do through the accessibility layer, you've found something a disabled person's assistive technology can't do either. So fix accessibility. Don't build a parallel system.

I filed an issue on the W3C WebMCP repo asking for a concrete use case that (1) can't be handled by the accessibility tree, (2) isn't better served by a backend API, and (3) wouldn't also benefit assistive technology if added to the accessibility layer.

Curious if anyone can produce one.