The browser as trust intermediary
A role distinct from the spoke’s founding assistant ↔ agent axis: the browser as the party that holds something neither the site nor the service will hand the other, and brokers between them.
The corpus has two instances, both Chrome origin trials.
chrome-built-in-ai puts Gemini Nano behind web-platform APIs. The site gets inference without the user’s page content leaving the device, and without the site paying a provider. The browser holds the model.
email-verification-protocol lets a site confirm you own an email address by having the browser ask your provider, using an ephemeral key and your existing first-party session. The issuer never learns which site asked; the site learns nothing until you submit. The browser holds the session, and the fact that it is a first-party session is the whole basis of the guarantee.
Why it is a distinct role
An assistant answers you. An agent acts for you. An intermediary does neither — it sits between two parties who don’t trust each other enough to talk directly, and its usefulness comes from being the only software with a legitimate view of both sides. It is the browser’s oldest job (TLS, the origin model, cookie scoping) reappearing at the application layer, and it is the one role a website cannot route around by shipping a better SPA.
The commercial consequence differs from the other two. Assistant and agent features are things a browser sells you — perplexity-comet at $200/mo, opera-neon at $19.90. Intermediary features are things a browser sells the web, and the payment is dependency. A site that drops its OTP flow for EVP now needs a browser that implements it, and a user whose provider participates.
What to watch
Whether the role stays open. Both instances are Chrome origin trials, and EVP’s working deployment is Google as browser, provider and issuer at once, under an open spec nobody else has implemented yet. “Open standard, one implementer” is stable for as long as the implementer wants it to be. The counter-case would be ladybird or a Gecko browser shipping EVP against a non-Google issuer; nothing in the corpus yet.
Related
email-verification-protocol · chrome-built-in-ai · chrome-built-in-ai-dos-donts · ai-browser · ladybird · synthesis