[Kitesurf] I let Claude drive Cloudflare's new Kitesurf browser: lighter browser, slower agent~

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Ciallo~(∠ ω< )⌒ ★ this is AnonymousPenguin~

Cloudflare made a new web browser just for AI agents. It's called Kitesurf, it runs on Cloudflare's servers, and it's free while it's in beta.

Cloudflare says it uses much less computer power than Chrome. But does it help the AI agent perform better?

So I gave the same jobs to an AI agent on four different browsers and compared the results~

Result first

No, Kitesurf didn't make my AI agent better. On simple pages it did just as well as Chrome. On harder pages, the agent needed more steps and more time, and it got one task wrong that every other browser got right.

Should you use it?

• ✅ Reading simple public pages: fine, same as Chrome.
• ⚠️ Lots of clicking through pages: works, but slower.
• ❌ Frames, big JavaScript sites, logins: avoid for now.

About this test:

• The agent: Claude Code with Claude Sonnet 5.5 (claude-sonnet-5-5).
• Each task was run once per browser.
• Kitesurf is a beta (version 0.0.1), so things may change.

What is Kitesurf?

Kitesurf is a browser Cloudflare built for AI agents.

• It's built from scratch, with no Chrome inside.
• It runs on Cloudflare's servers (Cloudflare Workers).
• Cloudflare says it uses 3–7 times less CPU and memory than Chrome, but is about 1.7 times slower. I didn't test this.
• It's free while in beta.

It even draws pages a bit differently (not really obvious, but the font style is different). Here's the same page as a screenshot from each:

Chrome (Cloudflare's normal browser):

Kitesurf:

How I tested

Four browsers

I also tested Cloudflare Chromium because it runs in the same place as Kitesurf but is a normal browser. So if Kitesurf does worse, it's Kitesurf's fault, not the distance.

Nine tasks

I worked out and recorded each task's correct answer in advance, using my laptop's browsers.

Rules (decided before testing)

Kitesurf doesn't help the agent if any of these happen:

1. It gets more than 1 extra task wrong compared with Chrome.
2. It needs more actions than Chrome.
3. It doesn't save at least 20% tokens compared with local headless (same tool, so a fair match).
4. It takes more than twice as long as Chrome.

How each run worked

For every task on every browser, I started a brand-new Claude agent with the exact same instructions. Only the browser was different. The agent decided by itself what to click and read. Claude Code counted its tokens, actions and time.

Detailed results

Per task (✅ correct, then actions / seconds):

Why did Cloudflare Chromium need 25 actions on A5? Not because of the browser. Its window is small by default, and at that size the page's footer covers the Search button, so its clicks hit the footer.

Checking the four rules

The cost of using the browser (tokens)

This is only what the agent spent on the browser: reading pages and thinking about them. The agent's own instructions and tool list are taken out (I measured them with agents that load the tools and do nothing).

Kitesurf's pages look smaller to the agent, but mostly because some content is missing, and the agent then spends extra actions looking for it.

Why Kitesurf did worse

1. Frames don't work. Pages inside a page (iframes) are always empty on Kitesurf, so the agent needed a workaround for Task A4.

2. Some pages come back empty. The AWS docs page stays hidden on Kitesurf, so the agent saw nothing and had to read the text another way.

3. After a click, the agent reads the old page. Kitesurf doesn't tell the tool "I'm going to a new page", so the tool thinks the click did nothing and lets the agent read too early.

4. aws.amazon.com freezes Kitesurf. The page never finishes loading, so the agent couldn't read the title (Task R4).

5. Kitesurf is slow at opening pages. Opening a page takes about 3x longer inside Kitesurf (about 0.4 s vs 0.13 s), even though Kitesurf's server was the closest to me.

What works and what doesn't

✅ Works

• Normal pages, forms, and shadow DOM.
• Running 3 Kitesurf browsers at the same time. Each one is separate: none of them can see the others' pages.

❌ Doesn't work

Good to know

• An unused Kitesurf browser stays alive for up to about 10 minutes (Cloudflare's docs say 60 s), even after your agent disconnects. You have to close it yourself.
• Usage and the dashboard (beta, as of 2026-10-23): Cloudflare Chromium showed up in the Browser Run dashboard and counted towards the Free plan's 10 minutes a day. Kitesurf didn't show up at all, and I used it for over 35 minutes in one day without being stopped.

So, when should you use Kitesurf?

If you use it with an agent, tell the agent to:

1. Check it really got Kitesurf (see the appendix).
2. Close pages when it's done.
3. Check the page content after every click.
4. Read the page with a script if the snapshot looks empty.

Limits of this test

• Each task ran only once per browser. Agents can differ by about ±2 actions on the same task, so only big differences mean something.
• Local Chrome (claude-in-chrome) uses a different tool, so it's not a perfect match.
• I didn't test CPU, memory or price.
• Tested on Claude Code 2.1.307 only (Cloudflare Chromium runs: 2.1.309).

Closing

A lighter browser is great for Cloudflare's servers, and maybe for your bill. But an AI agent doesn't care how light the browser is. It cares whether the page is really there, whether a click tells it what happened, and whether "success" really means success. Right now Kitesurf isn't better at any of these.

It's only a few months old, though, and changing fast. I'll happily test it again when it grows up~

Thank you for following along until here!

Adiós~ (｀・ω・´)ゞ

Appendix: Try it yourself

1. Make an API token

Create a Cloudflare API token that is allowed to use Browser Run.

2. Add Kitesurf to your agent

My .mcp.json. The token and account ID come from environment variables, so they're never written in the file:

{
  "mcpServers": {
    "kitesurf": {
      "command": "npx",
      "args": [
        "-y", "chrome-devtools-mcp@latest",
        "--wsEndpoint", "wss://api.cloudflare.com/client/v4/accounts/${CLOUDFLARE_ACCOUNT_ID}/browser-run/devtools/browser?browser=kitesurf",
        "--wsHeaders", "{\"Authorization\":\"Bearer ${CLOUDFLARE_API_TOKEN}\"}"
      ]
    }
  }
}

For Cloudflare Chromium, use the same thing without ?browser=kitesurf.

3. Check that you really got Kitesurf

Asking for Kitesurf doesn't mean you get Kitesurf. When I asked for it in a different way (an HTTP request instead of the direct connection above), I quietly got normal Chrome instead. No error, no warning.

So ask the browser who it is before you trust it:

() => ({
  ua: navigator.userAgent,                                         // "Kitesurf/0.0.1"
  webgl2: !!document.createElement('canvas').getContext('webgl2'), // false on Kitesurf
  chrome: typeof window.chrome                                     // "undefined" on Kitesurf
})

Don't check for WebGL (3D graphics) with typeof WebGL2RenderingContext. Kitesurf says "yes, I have it", but it's fake. Only getContext('webgl2') tells the truth.

4. Give the agent a job

Tell the agent to use the kitesurf tools, and off it goes~