Designing for a second audience

A page used to have one audience. Now it has two: the person looking at it, and an agent acting for that person. The guide I co-wrote with Kasper Kulikowski, “Build agent-friendly websites” on web.dev, is about the second one. These are my notes on it, written as a designer. The guide is the source, so start there for the full detail.

Agents read a page in more than one way

An agent can look at a screenshot, read the HTML, or read the accessibility tree, and agents typically cross-check them. A screenshot is slow and costly in tokens, so it works best as a fallback. The HTML shows which control belongs to which content. The accessibility tree strips the visual noise and says what each control does.

The design consequence is plain. A styled div that looks like a button but exposes nothing is a button to a person and may not be one to an agent.

The fixes are fundamentals

None of the recommendations is exotic:

• Use native buttons and links. If you cannot, add a role and a tabindex.
• Link every label to its input.
• Keep transparent overlays off interactive elements.
• Keep the controls a task needs visible and not too small.
• Keep controls in the same place from one page to the next. An add-to-cart button should not move between categories.

What I like about the list is that it never asks you to design for machines at the expense of people. The same changes tend to help human users too.

Tasks, with a check before the sensitive ones

The newer idea is WebMCP, a proposed standard that is still in development. It lets a site publish explicit tasks to agents instead of leaving them to infer the task from pixels. The guide suggests that sensitive actions can trigger a confirmation from the user.

That is the part I keep returning to. Who gets asked, and at what point, is a design decision, not a plumbing detail. I wrote more about the interruption itself in The moment nobody designs.

Where I would start

Audit your accessibility tree. If the hierarchy there is clear and stable, you have done most of the work.