Enabling "WebMCP for testing" flag

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Steve Molitor

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Mar 10, 2026, 12:16:41 PM (11 days ago) Mar 10
to Chrome Built-in AI Early Preview Program Discussions
I'm having trouble enabling the "WebMCP for testing" flag. 

As instructed in the WebMCP Early Preview Setup Instructions, I navigated to chrome://flags/#enable-webmcp-testing but I don't see the flag:

https://cdn.zappy.app/aebb84be35a22a7d893bbc5d84131875.png

flags.png
Am I not registered or something? I did complete the registration process, apparently successfully. Did the flag name change?

When I visit https://googlechromelabs.github.io/webmcp-tools/demos/react-flightsearch/ and click on the  Model Context Tool Inspector Extension, I get this error:
Error: You must run Chrome with the "WebMCP for testing" flag enabled.
That makes sense, but how do I enable the flag? 

Thanks,

Steve

Noah Mayerhofer

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Mar 10, 2026, 12:24:30 PM (11 days ago) Mar 10
to Chrome Built-in AI Early Preview Program Discussions, Steve Molitor
What version of chrome are you on?

You need to be on version 146.0.7672.0 or higher.
I needed to download the beta of chrome (https://www.google.com/intl/en_uk/chrome/beta/) since the rollout of the update has not me chrome yet.

// Noah

Steve Molitor

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Mar 10, 2026, 12:38:41 PM (11 days ago) Mar 10
to Chrome Built-in AI Early Preview Program Discussions, Noah Mayerhofer, Steve Molitor
Ah, that was it, thanks! 

I missed that in the instructions.

Thanks,

Steve

Noah Mayerhofer

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Mar 10, 2026, 5:48:58 PM (10 days ago) Mar 10
to Steve Molitor, Chrome Built-in AI Early Preview Program Discussions
Hi Steve,

No problem at all.

// Noah

Sumeet Singh

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Mar 11, 2026, 1:08:14 AM (10 days ago) Mar 11
to Noah Mayerhofer, Steve Molitor, Chrome Built-in AI Early Preview Program Discussions
Hi Steve,

The "WebMCP for testing" flag requires Chrome version 146.0.7672.0 or higher. If you don't see the flag at chrome://flags/#enable-webmcp-testing, please ensure you have updated your browser or download the Chrome Beta version, as the update may still be rolling out.

Best regards,

Sumeet Singh


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Jack H

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Mar 11, 2026, 8:02:52 PM (9 days ago) Mar 11
to Chrome Built-in AI Early Preview Program Discussions, Sumeet Singh, Steve Molitor, Chrome Built-in AI Early Preview Program Discussions, Noah Mayerhofer
I have found success using Chrome's Canary browser in Australia as I also don't see flags in my regular chrome browser
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