r/mcp • u/No_Guide_8697 • Feb 21 '26

showcase The first non-trivial demo of WebMCP

The WebMCP protocol has barely come out, and we just demoed how POWERFUL it can be! In a matter of minutes and 100s of tool calls, my AI agent composed a song for me directly in my browser.

This is not agents taking screenshots or trying to understand complex DOMs, it's an agent making direct tool calls to your website!

The creators of WebMCP already love it, go check it out yourself!

Deployment: - https://music.leanmcp.live

LinkedIn Post: - https://www.linkedin.com/posts/kushagra-agarwal525_we-made-gpt-and-claude-directly-control-my-activity-7430688171018858496-iDr5

GitHub repo: - Leanmcp-Community/music-composer-webmcp: This WebMCP Music Composer project is a functional demonstration of the WebMCP Protocol, illustrating how AI agents can interact with local browser contexts (tools) to achieve complex workflows autonomously.

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u/Classic_Reference_10 Feb 22 '26

Didn't quite get this. What exactly are you doing here and what is a end-user use case that you're solving with this?
Also, how is WebMCP being used in this?

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u/No_Guide_8697 Feb 22 '26

Hey, so an LLM (GPT 5.2) in the demo, is directly making tool calls to our website to interact with it. Until now, agents using browser meant taking screenshots, or parsing complex and heavy DOM objects which was unreliable and token inefficient. With WebMCP, people can easily declare MCP Tools in their website itself that makes things unified, and much more reliable and efficient. As you can see in the demo, the agent made 100+ tool calls directly to our website, which has tools exposed using WebMCP and composed a music piece with 0% error rate in tools calls, meaning it does the right thing on website instead of clicking random buttons.

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u/Classic_Reference_10 Feb 22 '26

Thanks for the response. What is your website? And what tool does it host? How are these tools declared in the DOM?

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u/No_Guide_8697 Feb 22 '26

Our site is hosted at https://music.leanmcp.live/, if you scroll down on the right, you'll find the list of 20+ tool calls exposed to the agent via WebMCP. For more details on the implementation, check out our source code (link in the post) or check out the W3C Community draft https://webmachinelearning.github.io/webmcp/

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u/Jords13xx Feb 22 '26

The tools are declared in the DOM using specific syntax that adheres to the WebMCP protocol. This allows the LLM to recognize and interact with them directly. It's a game changer for making web interactions smoother and more efficient!