feat: agentic browsing in lighthouse

[lusayaa]

pending GoogleChrome/lighthouse#16980

[matthiasrohmer]

A drive-by nit: this seems to fail when chrome://flags/#enable-webmcp-testing is not Enabled. Could that be? With Antigravity I get Protocol error (WebMCP.enable) if use a out of the box Chrome instance. Might be good to handle this error case, as I assume most people don't have it enabled by default and I am not too sure when it will be.

[OrKoN]

Interesting, the test tests/tools/lighthouse.test.ts seems to pass but I guess Lighthouse might be sending WebMCP.enable conditionally.

[lusayaa]

Ah I suppose that was kind of on purpose to surface an error with the backend. Does the whole lighthouse run fail for you or just the specific WebMCP audits? @matthiasrohmer

[matthiasrohmer]

Yep the whole run failed, and the agent just stopped. :)

[OrKoN]

I am not able to reproduce the error but I do not get a new category in the results (Chrome Canary, launched via build/src/bin/chrome-devtools-mcp.js --channel=canary --chrome-arg='--enable-features=WebMCPTesting,DevToolsWebMCPSupport'):

[OrKoN]

I am not able to reproduce the error but I do not get a new category in the results (Chrome Canary, launched via build/src/bin/chrome-devtools-mcp.js --channel=canary --chrome-arg='--enable-features=WebMCPTesting,DevToolsWebMCPSupport'):

I had a stale build somehow.

[OrKoN]

Discussed offline: this PR waits for a follow-up Lighthouse update