Wow, I hadn't heard of this!

  const audits = await pipeline(found.files, file =>
    agent(`Audit ${file} for missing authentication checks.`, { label: file }),
  )

I asked Claude in the browser if it could do anything like that. It wrote a little frontend app that calls the Anthropic API (with fetch()), without including a key. I expected that to fail, but it worked!

Apparently in the web chat (and also in Claude Code?[0] Though I haven't tried yet) they can call the Anthropic API and your subscription key gets auto-magicked into the requests somehow.

Those are two separate things of course (aside from the key-injection) but I guess there's no reason it couldn't run completely in the front-end... hmm...

[0] https://code.claude.com/docs/en/workflows