Ready for Developer Testing: WebMCP

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Chromestatus

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Feb 9, 2026, 7:41:05 PM (10 hours ago) Feb 9
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Contact emails
khusha...@chromium.org, skman...@google.com, be...@chromium.org, mas...@chromium.org

Explainer
https://github.com/webmachinelearning/webmcp

Specification
No information provided

Summary
WebMCP is a proposal for a web API that enables web pages to provide agent-specific paths in their UI. With WebMCP, agent-service interaction takes place via app-controlled UI, providing a shared context available to app, agent, and user.

Blink component
Blink>Agentic Platform>WebMCP

Web Feature ID
Missing feature

Search tags
WebMCP

Risks


Interoperability and Compatibility
Given this is a new space and new API - there's no compatibility risk. Usual risk related to other browser vendors not adopting the API apply. This API is meant to augment capabilities provided by browser add-ons and so non-adoption in other engines would have limited user-impact and thus we consider the risk to be low.

Gecko: No signal

WebKit: No signal

Web developers: No signals

Other signals:

WebView application risks

Does this intent deprecate or change behavior of existing APIs, such that it has potentially high risk for Android WebView-based applications?

No information provided


Debuggability
WebMCP will raise issues to a DevTools WebMCP Panel to help surface configuration errors, such as malformed structured schemas, improper function registration, and failed actuation attempts by the agent.

Will this feature be supported on all six Blink platforms (Windows, Mac, Linux, ChromeOS, Android, and Android WebView)?
Yes

Is this feature fully tested by web-platform-tests?
No
The IDL and basic usage is tested via WPTs. Since the API provides the user agent with the ability to call certain tools, we might need to extend the WPT harness to support this.

DevTrial instructions
https://docs.google.com/document/d/1rtU1fRPS0bMqd9abMG_hc6K9OAI6soUy3Kh00toAgyk/edit?tab=t.0

Flag name on about://flags
Experimental Web Platform features

Finch feature name
WebMCP

Requires code in //chrome?
True

Tracking bug
https://crbug.com/445637567

Estimated milestones
DevTrial on desktop146


Link to entry on the Chrome Platform Status
https://chromestatus.com/feature/5117755740913664

Links to previous Intent discussions
Intent to Prototype: https://groups.google.com/a/chromium.org/d/msgid/blink-dev/CANMmsAtRdyRw1WtO5va0K%3D_adYH-FRh01xvw5%2BosSd_DAq%3D%3DUQ%40mail.gmail.com


This intent message was generated by Chrome Platform Status.

Tom Jones

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Feb 9, 2026, 8:17:29 PM (9 hours ago) Feb 9
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based on the explainer there has been no security review.
Are any W3C reviews in process?
I couldn't tell if anyone was addressing/prototyping A2A?

I believe this would be a privacy nightmare for any user of a browser enabling this and will create a threat model for W3C SING if no one is currently underway.

Peace ..tom jones


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Johann Hofmann

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12:26 AM (5 hours ago) 12:26 AM
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Hi Tom, the team is working both with Chrome Security and in the W3C WebML CG (see P&S considerations) to figure out these challenges, with bi-weekly CG meetings where security and privacy questions are actively being discussed. I agree that there is a lot we have to get right here, and we'll involve TAG and others for help and review as per the process. Note that this is an early prototype for developer testing and not an intent to to ship.

I'm happy to join any SING call if you'd like to discuss this further.

Thanks!

Johann

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