In May 2025 we released an open agent identity standard, ACK-ID. A lot of what we proposed has since been adopted, and today we put up an RFC for v2:
A simpler agent identity and permission layer that interops with Web Bot Auth, x402, and whatever comes next.
Why we changed it:
cirBTC is live on @ethereum.
Circle helped establish the institutional standard for dollar collateral with USDC.
Now cirBTC brings that same approach to Bitcoin, bringing 1:1 BTC-backed collateral to institutional DeFi markets with neutrality, transparency, and Circle
