# What changed in lighthouse

> 38 changes in lighthouse 13 from its official release notes, upgrade guides and advisories: 2 breaking, 1 security, 12 new APIs and options. Each one cited. Sources checked 2026-10-18. HTML: https://unstale.sh/npm/lighthouse/

To see which of these apply to a repository, run `npx @unstale/cli init` in it.

## lighthouse 13

### Breaking changes

- WebMCP snapshot mode was removed. (13.4.1) — [release notes](https://github.com/GoogleChrome/lighthouse/releases/tag/v13.4.1)
- Adds a baseline compatibility audit and includes it in the default configuration, so Lighthouse runs it by default. (13.1.0) — [release notes](https://github.com/GoogleChrome/lighthouse/releases/tag/v13.1.0)

### Security

- Sanitizes entity homepage URLs in reports. (13.5.0) — [release notes](https://github.com/GoogleChrome/lighthouse/releases/tag/v13.5.0)

### New APIs and options

- Adds the Agent Resource Discovery audit. (13.5.0) — [release notes](https://github.com/GoogleChrome/lighthouse/releases/tag/v13.5.0)
- The viewer enabled the Agentic Browsing category via the PSI API. (13.4.1) — [release notes](https://github.com/GoogleChrome/lighthouse/releases/tag/v13.4.1)
- Adds evaluateOnObject to ExecutionContext for evaluating on an object. (13.4.0) — [release notes](https://github.com/GoogleChrome/lighthouse/releases/tag/v13.4.0)
- Lighthouse now provides a public types entrypoint for importing its types. (13.4.0) — [release notes](https://github.com/GoogleChrome/lighthouse/releases/tag/v13.4.0)
- A new agentic browsing category is added to the default config. (13.3.0) — [release notes](https://github.com/GoogleChrome/lighthouse/releases/tag/v13.3.0)
- Adds a new agentic browsing category, with accessibility audits enabled and aggregated for the category. (13.2.0) — [release notes](https://github.com/GoogleChrome/lighthouse/releases/tag/v13.2.0)
- Adds an llms.txt check for AI agents and refines its validation logic. (13.2.0) — [release notes](https://github.com/GoogleChrome/lighthouse/releases/tag/v13.2.0)
- Adds an audit for missing WebMCP tool annotations. (13.2.0) — [release notes](https://github.com/GoogleChrome/lighthouse/releases/tag/v13.2.0)
- Adds an audit that lists registered WebMCP tools. (13.2.0) — [release notes](https://github.com/GoogleChrome/lighthouse/releases/tag/v13.2.0)
- Adds an audit that checks for WebMCP schema issues. (13.2.0) — [release notes](https://github.com/GoogleChrome/lighthouse/releases/tag/v13.2.0)
- Adds a WebDX feature usage trace category. (13.1.0) — [release notes](https://github.com/GoogleChrome/lighthouse/releases/tag/v13.1.0)
- The robots-txt audit now supports the Content-Signal directive. (13.0.2) — [release notes](https://github.com/GoogleChrome/lighthouse/releases/tag/v13.0.2)

### Behavior and default changes

- Groups the llms.txt and ARD audits under agent discovery. (13.5.0) — [release notes](https://github.com/GoogleChrome/lighthouse/releases/tag/v13.5.0)
- User flows can abort pending navigations. (13.5.0) — [release notes](https://github.com/GoogleChrome/lighthouse/releases/tag/v13.5.0)
- Plugin category validation is centralized and enforced. (13.5.0) — [release notes](https://github.com/GoogleChrome/lighthouse/releases/tag/v13.5.0)
- Plugin versions are included in LHR credits. (13.5.0) — [release notes](https://github.com/GoogleChrome/lighthouse/releases/tag/v13.5.0)
- Displays plugins in the report footer. (13.5.0) — [release notes](https://github.com/GoogleChrome/lighthouse/releases/tag/v13.5.0)
- Warns when the recommended limit is exceeded. (13.5.0) — [release notes](https://github.com/GoogleChrome/lighthouse/releases/tag/v13.5.0)
- WebMCP gatherers now check document.modelContext. (13.4.1) — [release notes](https://github.com/GoogleChrome/lighthouse/releases/tag/v13.4.1)
- Improved Dynamic Baseline High calculation and feature summaries, affecting the baseline results Lighthouse reports. (13.4.1) — [release notes](https://github.com/GoogleChrome/lighthouse/releases/tag/v13.4.1)
- Lighthouse now provides detailed error messages when fetching llms.txt fails. (13.4.1) — [release notes](https://github.com/GoogleChrome/lighthouse/releases/tag/v13.4.1)
- Lighthouse now provides detailed error messages when fetching robots.txt fails. (13.4.1) — [release notes](https://github.com/GoogleChrome/lighthouse/releases/tag/v13.4.1)
- Moves specific accessibility audits into the default configuration. (13.2.0) — [release notes](https://github.com/GoogleChrome/lighthouse/releases/tag/v13.2.0)
- Adjusts how WebMCP audits behave when WebMCP is unsupported. (13.2.0) — [release notes](https://github.com/GoogleChrome/lighthouse/releases/tag/v13.2.0)
- The baseline audit report now includes baseline icons. (13.1.0) — [release notes](https://github.com/GoogleChrome/lighthouse/releases/tag/v13.1.0)
- Reverts strict wrapping of network requests, changing how Lighthouse handles those requests. (13.1.0) — [release notes](https://github.com/GoogleChrome/lighthouse/releases/tag/v13.1.0)
- The valid language list used for hreflang checks was updated, which may affect Lighthouse audit results. (13.0.2) — [release notes](https://github.com/GoogleChrome/lighthouse/releases/tag/v13.0.2)

### Fixes and other changes

- Passes instead of reporting n/a when all forms are covered. (13.5.0) — [release notes](https://github.com/GoogleChrome/lighthouse/releases/tag/v13.5.0)
- Validation for invalid URLs in the canonical audit has been improved. (13.4.0) — [release notes](https://github.com/GoogleChrome/lighthouse/releases/tag/v13.4.0)
- The header check now allows leading whitespace. (13.4.0) — [release notes](https://github.com/GoogleChrome/lighthouse/releases/tag/v13.4.0)
- Implements a UKM Invalidate fallback for LCP. (13.2.0) — [release notes](https://github.com/GoogleChrome/lighthouse/releases/tag/v13.2.0)
- The baseline audit description now includes the web-feature version. (13.1.0) — [release notes](https://github.com/GoogleChrome/lighthouse/releases/tag/v13.1.0)
- Fixed focus behavior in DevTools and its three-dot menu. (13.0.2) — [release notes](https://github.com/GoogleChrome/lighthouse/releases/tag/v13.0.2)
- Fixed tooltip positioning in DevTools. (13.0.2) — [release notes](https://github.com/GoogleChrome/lighthouse/releases/tag/v13.0.2)
- Fixed the incorrect DPR used for responsive images advice. (13.0.1) — [release notes](https://github.com/GoogleChrome/lighthouse/releases/tag/v13.0.1)