I like this! This seems like a cool way to think about building a continuous testing suite (or a CI system) for agents as they evolve.

Adding to the list - Pangea AuthN

I work at Pangea, and while I believe many of the other AuthN options listed are also easy to integrate into your apps, not many provide MFA and passkeys out of the box. Pangea offers MFA + passkeys out of the box and threat intel IP datasets to block bots from signing up / logging in. All of this comes out of the box :)

https://pangea.cloud/services/authn/

I knew I forgot one! Just added.

I wrote a small snippet of code that lets you enable a "Login with Passkeys" button in any React/NextJS app