Chrome Built-in AI APIs unavailable with origin tokens on Vercel (Dev/Canary)

Summary
The Chrome Built-in AI APIs aren’t available on my deployed app even though an origin token is configured per the docs (added to responses and verified in the page). API objects are not exposed and related calls fail.

Environment

Hosting: Vercel (HTTPS, production domain)

Browsers: Chrome Dev and Chrome Canary (latest builds as of Oct 11, 2025)

Platform: Web app using the Prompt/Summarizer/Translator APIs (Chrome Built-in AI)

Token setup: Origin token added to response headers / meta as required

Repro steps

Deploy app to Vercel at the production origin.

Add the origin token (served on first-party pages).

Open the site in Chrome Dev and Canary.

Attempt to access the Built-in AI APIs (e.g., window.ai / feature entry points) and make a simple call.

Expected
API objects available and calls succeed when the page is served from the configured origin.

Actual
APIs remain unavailable (objects not exposed and calls fail).

What I already tried

Verified the origin token is present on the page (in response headers/meta).

Hard refresh, cache clear, new Chrome profile, extensions disabled.

Tested in both Dev and Canary on multiple machines.

Confirmed the origin matches the deployed site and that the page is top-level (not in an iframe).

Questions for the Google team

Is there an additional enablement/approval step after adding the origin token?

Are there current allowlists, staged rollouts, or region restrictions that could block access?

Any known issues with Vercel/static hosting setups for origin tokens?

Recommended debugging steps to validate token recognition on the Chrome side?

Shareables

Live: https://focusmate-tau.vercel.app/

Repo: https://github.com/ChimdumebiNebolisa/focusmate