> [!WARNING]
> **Experimental:** The Agentic Browsing category and WebMCP support are experimental and based on proposed standards.

The Agentic Browsing category evaluates how well your site is constructed for
machine interaction through a set of deterministic audits.

## How the category is scored

Unlike other Lighthouse categories, the Agentic Browsing category does not have
a weighted average score from 0 to 100. Because the standards for the agentic
web are still emerging, the current focus is to gather data and provide
actionable signals rather than a definitive ranking.

Instead of a score, the report displays:

- **A fractional score**: A ratio showing how many agentic readiness checks your site passes.
- **Pass or Fail status**: Specific audits may emit errors or warnings if technical requirements (like WebMCP schema validity) are not met.
- **Informational counts** : The category header may include a *pass ratio* to help you observe overall progress at a glance.

## Why results fluctuate

While the audits are deterministic, your results may fluctuate due to changes in
how your site registers its tools or responds to agentic requests. Common causes
include:

- **Dynamic tool registration** : If your site registers WebMCP tools using JavaScript ([Imperative API](https://developer.chrome.com/docs/ai/webmcp/imperative-api)), the timing of these registrations can affect whether they are captured during the Lighthouse snapshot.
- **Variability in A11y tree construction**: Significant changes to DOM size or complexity can impact the structure of the accessibility tree, which is a core metric for agentic navigation.
- **Cumulative Layout Shift (CLS)**: Layout shifts caused by ads, images without dimensions, or injected content can move elements between the time an agent identifies them and the time it attempts an interaction.

## How audits are determined

Lighthouse uses a set of deterministic signals to evaluate your page. This
ensures that the audits are reproducible and suitable for integration into CI/CD
pipelines.

### WebMCP Integration

Lighthouse calls the Chrome DevTools Protocol (CDP) `WebMCP` domain to monitor
tool registration events. It verifies both declarative tools (defined in HTML)
and imperative tools (defined in JS).

### Agent-Centric Accessibility

Agents rely on the accessibility tree as their primary data model. Lighthouse
filters a specific subset of accessibility audits that are critical for machine
interaction, such as:

- **Names and labels**: Ensuring every interactive element has a programmatic name.
- **Tree integrity**: Verifying that roles and parent-child relationships are valid.
- **Visibility**: Confirming that content is not hidden from the accessibility tree while being interactive.

### Stability and Discoverability

- **Cumulative Layout Shift (CLS)**: Measures visual stability, which is critical for agents relying on element positioning.
- **llms.txt**: Checks for the presence of a machine-readable summary at the domain root.

## What can developers do to improve?

To improve your site's agentic readiness:

- **Adopt WebMCP**: Use the WebMCP API to explicitly expose your site's logic and forms to AI agents.
- **Ensure a sound a11y tree**: Prioritize semantic HTML and proper ARIA labeling, as these are the "machine-eye view" of your page.
- **Optimize for stability**: Reduce layout shifts to ensure that agents can reliably interact with your UI without elements moving unexpectedly.

## Feedback

If you encounter bugs or have suggestions for changes to the agentic browsing
audit:
[File an issue on GitHub](https://github.com/GoogleChrome/lighthouse/issues)