Google checks websites for llms.txt in new agentic browsing audit

Google is testing how well websites handle AI agents through a new experimental category called "Agentic Browsing" in its Lighthouse analysis tool. The category is based on proposed standards and isn't final yet. It still matters for users, because agents are supposed to reliably fill out forms, make bookings, or compare products down the line, provided pages are built to be machine-readable.

Unlike classic Lighthouse tests, there's no score from 0 to 100. You just get a ratio of passed checks. The audit covers integration of Google's own WebMCP API, which lets developers expose logic and forms specifically to agents, the accessibility tree as the core data model for machines, visual stability via Cumulative Layout Shift (CLS), and whether an llms.txt file is present.