Add implementation-status.md to track browser implementation status

[beaufortfrancois]

This PR adds an implementation-status.md file to track the implementation status of WebMCP across browser engines (Brave, Chrome, Firefox, Safari).

Following established practices in other W3C Community Groups and Web Standards repositories (such as Web Bluetooth and WebGPU), maintaining a dedicated implementation status document provides a central, up-to-date reference for web developers, spec authors, and browser vendors.

This document will be updated periodically as browser support and standards positions evolve.

[beaufortfrancois]

@bwalderman Let me know if there's anything we can add for Edge/Copilot.

[bwalderman]

@bwalderman Let me know if there's anything we can add for Edge/Copilot.

Thanks @beaufortfrancois , I've made a suggestion which includes Microsoft's origin trial link for WebMCP. Platform support is naturally at parity with Chromium. We don't have any links to share about in-browser Copilot integration at this time.

[domfarolino]

Should this just be a section in the main explainer?

[beaufortfrancois]

Should this just be a section in the main explainer?

I think it's better for discoverability to have it in a separate file.

[bwalderman]

Should this just be a section in the main explainer?

I think it's better for discoverability to have it in a separate file.

Maybe a link at the top of the main explainer?

[beaufortfrancois]

Should this just be a section in the main explainer?

I think it's better for discoverability to have it in a separate file.

Maybe a link at the top of the main explainer?

Done

[beaufortfrancois]

@domfarolino I think we're good now.

[Idan-Levin]

Thank you! We added it to our WebMCP directory. We’re also tracking two more adoption signals: agents that support WebMCP, and agent frameworks/infrastructure that support WebMCP.

[beaufortfrancois]

Hey @Idan-Levin, I'm glad it's already useful.

May I note that "Goes GA in Chrome 157" isn't true. An origin trial phase is there to experiment. There's no contract to say it's going to ship after OT ends. See https://www.chromium.org/blink/origin-trials/running-an-origin-trial/ for more details.

[Idan-Levin]

@beaufortfrancois of course, will change now. It is based on this resource which might be worth updating: https://chromestatus.com/feature/5117755740913664

[beaufortfrancois]

I agree this is definitely misleading

[beaufortfrancois]

@domfarolino Can we merge this PR now?

[domfarolino]

Yep I think so! Thanks for all the work on this!