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Browser Run Now Speaks WebMCP: Agents Call Website Tools Directly!

Cloudflare Changelog ★★★ View Markdown
#cloudflare#ai#serverless#web

Hey there, it's Shiichan! Today's news changes how AI agents get along with the browser a little.

Cloudflare Changelog developers.cloudflare.com

What was announced?

Browser Run (formerly Browser Rendering) now supports WebMCP (Web Model Context Protocol), according to Cloudflare's Changelog. WebMCP is a new browser API from the Google Chrome team.

The story so far

The Internet was built for humans, so having an AI agent drive a browser has been pretty unreliable. Agents had to loop through screenshot, analyze, and click, which is slow and fragile.

What changes

With WebMCP, a website can expose "tools" for agents to use. An agent can call functions like searchFlights() or bookTicket() directly with typed parameters, making browser automation faster, more reliable, and less fragile.

Dive Deep

Here is what WebMCP lets you do.

  • Use navigator.modelContextTesting.listTools() to see the tools a site offers
  • Use navigator.modelContextTesting.executeTool() to run a tool with typed parameters
  • Support human-in-the-loop, where sensitive actions pause for user confirmation

WebMCP requires Chrome beta features. Cloudflare provides an experimental pool with Chrome beta instances, so you can test emerging browser features before they reach stable Chrome. To start a session, just add lab=true to your /devtools/browser request.

curl -X POST "https://api.cloudflare.com/client/v4/accounts/{account_id}/browser-rendering/devtools/browser?lab=true&keep_alive=300000" \
  -H "Authorization: Bearer {api_token}"

Combined with the recently launched CDP endpoint, you can connect an MCP client to Browser Run so your agent can discover and call website tools directly.

For a step-by-step guide, see the WebMCP documentation.

Wrap-up

  • Browser Run now supports WebMCP, so websites can expose tools for agents
  • Moves from the slow screenshot-analyze-click loop to direct typed function calls
  • Testable in the Chrome beta experimental pool (lab=true), and works with MCP clients over CDP
  • A treat for anyone building browser automation or AI agents!

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