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Audit7 min read

Chrome added an Agentic Browsing audit to Lighthouse — here's what it scores

Lighthouse now scores how easy your site is for AI agents to navigate, transact on, and cite. We break down every audit in the new category and what it takes to pass.

BridgeToAgentEditorial team

Chrome added an Agentic Browsing audit to Lighthouse

In late 2025 Chrome shipped a new category to Lighthouse: Agentic Browsing. It sits alongside Performance, Accessibility, Best Practices, and SEO — the four categories most teams already optimize against — and scores something none of those touch: how easy your site is for an AI agent to read, understand, and transact on.

If you make money from a website in 2026, this is the first audit your new traffic source is going to fail.

This post is the breakdown: what each audit checks, why Chrome added it, and what it takes to pass.

Update May 20, 2026: Lighthouse 13.3.0 (released May 7, 2026) moved Agentic Browsing into the default config. PageSpeed Insights inherits within two weeks; Chrome 150 DevTools follows. The audits below are unchanged at the spec level — what changed is that every Lighthouse run now returns them automatically, including the ones run by your customers, prospects, and partners. The full spec lives at developer.chrome.com/docs/lighthouse/agentic-browsing/scoring.

Why Chrome did this

The short version: Chrome can see that agentic browsing is happening. Operator, Computer Use, Project Mariner, Perplexity, ChatGPT's browse mode — a meaningful and growing share of the requests hitting public web servers are agents, not humans. Most of those agents fail at most sites, most of the time. The reason is structural: the modern web was built for a graphical browser rendered to a human eye, not for a language model with a 50-kB context budget.

Chrome decided the cheapest place to fix this is at audit time. If you can't pass the Agentic Browsing category, you don't get the agent traffic. That's the whole game.

The audits, one by one

llms-txt-present

What it checks: Whether https://yourdomain.com/llms.txt returns a 200 with a plausible plain-text content type.

Why it matters: llms.txt is the curated reading list an LLM fetches when it lands on your domain. Without it, the model picks URLs at random.

What it takes to pass: Ship a file. The format is small enough that a senior engineer can hand-write one in an afternoon for a 5-page site. For larger sites, the file needs to be generated from the real DOM — which is what the BridgeToAgent kit does.

llms-txt-well-formed

What it checks: Parseability against the llmstxt.org reference parser. Headings, bullets, link syntax all valid.

Why it matters: A malformed file gets ignored. A model that can't parse the manifest reverts to URL guessing, which is what we were trying to avoid.

What it takes to pass: Run your file through the reference parser before shipping. The BridgeToAgent generator does this as a build gate — malformed kits never leave the server.

agents-json-present

What it checks: /agents.json returns valid JSON with the right content type.

Why it matters: agents.json is the control panel — it tells an agent what it can do on your site. Search, request a quote, add to cart. Without it, the agent has to scrape your forms.

What it takes to pass: A typed manifest of your site's public actions. See our docs on the format for the shape.

agents-json-actions-typed

What it checks: That every action declared has at least one typed parameter, or parameters: [] if intentionally zero-arg.

Why it matters: Untyped actions are unreliable. An agent calling a search endpoint needs to know whether q is a string or an array, and whether it's required.

What it takes to pass: Be explicit. No "parameters": null.

schema-org-density

What it checks: Schema.org JSON-LD blocks on the homepage and on primary product/article pages, above a minimum density threshold (one typed block per major page at current settings).

Why it matters: Schema.org is how an agent decides what kind of page it's looking at without parsing the human copy. A Product block tells it "you can act on this — there's a price and an identifier." An Article block tells it "you can cite this — there's an author and a date." A FAQPage block tells it "extract these question-answer pairs verbatim."

What it takes to pass: Most CMS platforms have a one-click Schema toggle. WordPress: Yoast or RankMath. Shopify: built into theme metadata. Webflow: the new structured-data field on collection items. The audit summary the BridgeToAgent kit ships flags every page that needs Schema and what type to add.

sitemap-discoverable

What it checks: /sitemap.xml is valid and referenced from /robots.txt.

Why it matters: A sitemap is the agent's URL inventory. Without it, the agent walks the homepage navigation and prays. Most sitemaps are auto-generated; the failure mode is forgetting to reference them from robots.txt.

What it takes to pass: Add the line:

Sitemap: https://yourdomain.com/sitemap.xml

to your robots.txt. One line. Two minutes.

agent-runbook-present

What it checks: Whether agent-instructions.md is fetchable from the root path.

Why it matters: This is the file that tells the agent how to behave: how to quote prices, where to find canonical answers, which content to summarize vs. link. It's the difference between an agent confidently mis-quoting your shipping policy and an agent deferring to your shipping page.

What it takes to pass: A plain Markdown file. See our docs for the structure we recommend.

auto-discovery-links

What it checks: The homepage <head> contains <link rel="alternate"> references to the kit files, so an agent can find them from a single HTTP request to the root.

Why it matters: Saves the agent a round-trip per file. On large sites this is the difference between an agent succeeding within its context budget and timing out.

What it takes to pass: Three <link> tags in your homepage <head>. The platform-specific install guides we ship have the copy-paste snippet for every major CMS.

webmcp-annotations (emerging)

What it checks: WebMCP-style per-element annotations on interactive elements — <button>, <form>, <input> — that tell an agent what each control does and how to invoke it.

Why it matters: This is the future-state agent surface. It moves the action manifest from a separate file (agents.json) into the page itself, the same way Schema.org moved structured data from sidecar XML into the HTML.

What it takes to pass: Not yet, realistically. The WebMCP spec is still moving. The honest answer is that this audit may fail on every site today and that's OK — Lighthouse weights it lower than the core audits while the standard stabilizes. We'll ship WebMCP-annotated kit output as a free add-on the moment the spec lands.

What a typical score looks like

Sites with no kit installed score in the 10–30 range — usually they pass sitemap-discoverable, sometimes pass schema-org-density if they're on a modern CMS with built-in Schema, and fail everything else.

Sites with a kit installed cleanly score 75 or higher. The remaining ~25 points come from:

  • WebMCP annotations (waiting on spec)
  • Sitemap hygiene specific to the platform
  • Schema.org density on individual product/article pages

We surface all three in the free readiness audit at bridgetoagent.com so you know exactly which gaps are inside the kit's scope and which need a CMS-side fix.

How to run it on your site

As of Lighthouse 13.3.0 (May 7, 2026), Agentic Browsing ships in the default config. The fastest paths to run it:

  • PageSpeed Insights — open pagespeed.web.dev and enter your URL. PSI inherits the 13.3.0 default config within two weeks of release, so by the time you read this it should be returning the Agentic Browsing audits automatically.
  • Chrome DevTools (Chrome 150+) — open DevTools → Lighthouse → Analyze. The category is on by default; no toggle needed.
  • Chrome 130–149 — the category exists but stays behind the experimental toggle. Enable "Agentic Browsing" under Categories before running.
  • Lighthouse CLI — npx lighthouse@latest <url> --only-categories=agentic-browsing returns the JSON with per-audit pass/fail data for CI pipelines.

If you don't want to wait, the free readiness audit we run replicates the public-spec checks and gives you the same per-audit signals Chrome will, in five seconds, with no install.

The bigger pattern

Lighthouse is how Google operationalizes web-quality opinions at scale. When Lighthouse adds a category, the rest of the web optimization industry follows — within 18 months it becomes table stakes. That's what happened with Core Web Vitals. That's what happened with Accessibility. That's what's starting to happen with Agentic Browsing.

The window where this is differentiating closes faster than most teams expect — and 13.3.0 just narrowed it sharply. Default-config means every PSI run, every web.dev/measure check, every SEO-audit SaaS that wraps Lighthouse now surfaces the Agentic Browsing audits to the person paying attention. The sites that ship the kit in the next few weeks pass the audit before their competitors notice the audit exists. That's the whole opportunity.

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