> What can MCP enable? 1) Agents can access your Google Calendar and Notion, acting as a more personalized AI assistant. 2) Claude Code can generate an entire web app using a Figma design. 3) Enterprise chatbots can connect to multiple databases across an organization, empowering users to analyze data using chat. 4) AI models can create 3D designs on Blender and print them out using a 3D printer.
Sure 1 and 3 make sense if they mean "summarize" and not "analyze", 4 maybe, but 2... Oh I don't know where to begin other than to say that even really smart humans have a very hard time dealing with that task based on a figma doc. Wouldn't it make more sense to generate the figma doc if they're already that awful to begin with?
I had to skim through this a couple times before I realized that I still need to run an MCP server locally. This is basically a proxy between an LLM and the proposed protocol.
It’s a nice proof of concept.
And makes sense that the goal would be for LLM clients to adopt and support the standard natively. Then the proxy won’t be necessary.
That's not how I'd describe it- it's not meant to centralize servers, it's the idea: maybe you don't need to build and distribute a separate downloadable thing for users to interact with your service/product/whatever via agent, and instead they continue to use your website via an appropriate interface for agents.
The npm package is only there as the browser doesn't natively support the behavior (yet). Similarly MCP clients don't have built in support. So it's a bridge/proxy to demonstrate what could be done.
This seems like a security nightmare, a way to inject insecure content onto everyone's PC which can then automate actions executed with full user/admin privileges?
I attempted to acknowledge the security implications and am not trying to push this as a product/service - this was just a proposal.
Despite it being a proposal, I added token based authentication to mitigate potential abuse by forcing users to intentionally authenticate with a website before it can be used.
> Standardization effort: We're working to standardize all of these APIs for cross-browser compatibility.
> The Language Detector API and Translator API have been adopted by the W3C WebML Working Group. We've asked Mozilla and WebKit for their standards positions.
> The Summarizer API, Writer API, and Rewriter API have also been adopted by the W3C WebML Working Group. We've asked asked Mozilla and WebKit for their standards positions.
> We're launching today a public preview for the new Chrome DevTools Model Context Protocol (MCP) server, bringing the power of Chrome DevTools to AI coding assistants.
> Coding agents face a fundamental problem: they are not able to see what the code they generate actually does when it runs in the browser. They're effectively programming with a blindfold on.
> The Chrome DevTools MCP server changes this. AI coding assistants are able to debug web pages directly in Chrome, and benefit from DevTools debugging capabilities and performance insights. This improves their accuracy when identifying and fixing issues.
How could the Chrome DevTools MCP be integrated with the Gemini Computer Use model?
> Competency Story: The customer and product owner can write BDD tests in order to validate the app against the requirements
> Prompt: Write playwright tests for #token_reference, that run a named factored-out login sequence, and then test as human user would that: when you click on Home that it navigates to / (given browser MCP and recently the Gemini 2.5 Computer Operator model)
This explains all the new random GPO settings I had to go disable at the office this week! (A lot of users are reporting performance issues with browsers, seems like all the browsers are adding AI things... seems like a good place to start.)
jasonjmcghee|4 months ago
A lot has happened since I proposed / built this.
WebMCP is being incubated in W3C / webmachinelearning, so highly recommend checking that out as it's what will turn into WebMCP being in your browser.
https://github.com/webmachinelearning/webmcp
koolala|4 months ago
huflungdung|4 months ago
[deleted]
miguelspizza|4 months ago
If anyone wants to test out WebMCP, you can go to: https://webmcp.sh/ (this is a WebMCP server)
With the MCP-B chrome extension (this is a WebMCP client): https://chromewebstore.google.com/detail/mcp-b-extension/dao...
and use it to call WebMCP tools
sublinear|4 months ago
> What can MCP enable? 1) Agents can access your Google Calendar and Notion, acting as a more personalized AI assistant. 2) Claude Code can generate an entire web app using a Figma design. 3) Enterprise chatbots can connect to multiple databases across an organization, empowering users to analyze data using chat. 4) AI models can create 3D designs on Blender and print them out using a 3D printer.
Sure 1 and 3 make sense if they mean "summarize" and not "analyze", 4 maybe, but 2... Oh I don't know where to begin other than to say that even really smart humans have a very hard time dealing with that task based on a figma doc. Wouldn't it make more sense to generate the figma doc if they're already that awful to begin with?
tobyjsullivan|4 months ago
It’s a nice proof of concept.
And makes sense that the goal would be for LLM clients to adopt and support the standard natively. Then the proxy won’t be necessary.
koolala|4 months ago
mrasong|4 months ago
Didn’t expect WebMCP to let you build custom MCP clients too. That’s actually way more flexible!
socketcluster|4 months ago
The current and potential benefits are:
- Consistent authentication mechanism for all tools.
- Ease of tool registration/deregistration.
- Tool discovery.
Main drawbacks are:
- Trusting WebMCP npm package to run on your users' computers.
- Trusting WebMCP with access to your site or platform's functionality. Kind of like OAuth?
Does this sound right? Any other pros and cons versus integrating MCP server directly with specific LLMs?
jasonjmcghee|4 months ago
(Here's another comment with an explanation https://news.ycombinator.com/item?id=45623782)
The npm package is only there as the browser doesn't natively support the behavior (yet). Similarly MCP clients don't have built in support. So it's a bridge/proxy to demonstrate what could be done.
dogma1138|4 months ago
pjmlp|4 months ago
saberience|4 months ago
Why on Earth would I want this?
jasonjmcghee|4 months ago
https://github.com/webmachinelearning/webmcp
I attempted to acknowledge the security implications and am not trying to push this as a product/service - this was just a proposal.
Despite it being a proposal, I added token based authentication to mitigate potential abuse by forcing users to intentionally authenticate with a website before it can be used.
ngc6677|4 months ago
westurner|4 months ago
W3C Process document > 3.4. Chartered Groups: Working Groups and Interest Groups: https://www.w3.org/policies/process/#GAGeneral
There's WebGPU, WebNN, window.ai, Prompt API, Summarizer API, Writer API, Rewriter API, Language Detector API, Translator API ; and now WebMCP
WebNN: https://www.w3.org/TR/webnn/
webmachinelearning/prompt-api > "Explainer for the Prompt API": https://github.com/webmachinelearning/prompt-api
https://developer.chrome.com/docs/ai/built-in :
> Standardization effort: We're working to standardize all of these APIs for cross-browser compatibility.
> The Language Detector API and Translator API have been adopted by the W3C WebML Working Group. We've asked Mozilla and WebKit for their standards positions.
> The Summarizer API, Writer API, and Rewriter API have also been adopted by the W3C WebML Working Group. We've asked asked Mozilla and WebKit for their standards positions.
webmachinelearning/webmcp: https://github.com/webmachinelearning/webmcp
jasonjmcghee/WebMCP: https://github.com/jasonjmcghee/WebMCP
Having worked on at least one web app with a name that started with "Web", I'm not surprised.
/? mcp chrome: https://hn.algolia.com/?dateRange=all&page=0&prefix=false&qu... :
- "Show HN: We packaged an MCP server inside Chromium" (today) https://news.ycombinator.com/item?id=45618536 re: browseros-mcp: https://github.com/browseros-ai/BrowserOS/blob/main/docs/bro...
- "Chrome DevTools (MCP) for your AI agent" https://developer.chrome.com/blog/chrome-devtools-mcp .. https://news.ycombinator.com/item?id=45412734 (September 2025) .. :
> We're launching today a public preview for the new Chrome DevTools Model Context Protocol (MCP) server, bringing the power of Chrome DevTools to AI coding assistants.
> Coding agents face a fundamental problem: they are not able to see what the code they generate actually does when it runs in the browser. They're effectively programming with a blindfold on.
> The Chrome DevTools MCP server changes this. AI coding assistants are able to debug web pages directly in Chrome, and benefit from DevTools debugging capabilities and performance insights. This improves their accuracy when identifying and fixing issues.
How could the Chrome DevTools MCP be integrated with the Gemini Computer Use model?
From https://news.ycombinator.com/item?id=45543923 :
> Competency Story: The customer and product owner can write BDD tests in order to validate the app against the requirements
> Prompt: Write playwright tests for #token_reference, that run a named factored-out login sequence, and then test as human user would that: when you click on Home that it navigates to / (given browser MCP and recently the Gemini 2.5 Computer Operator model)
"Introducing the Gemini 2.5 Computer Use model" (October 2025) https://blog.google/technology/google-deepmind/gemini-comput...
Could this help with accessibility reviews?
"Lighthouse accessibility score" https://developer.chrome.com/docs/lighthouse/accessibility/s...
awesome-a11y > Tools: https://github.com/brunopulis/awesome-a11y/blob/main/topics/...
ocdtrekkie|4 months ago
unknown|4 months ago
[deleted]
hhthrowaway1230|4 months ago
brazukadev|4 months ago
meindnoch|4 months ago
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