What's the advantage in putting agents in the persistence layer rather than the application layer? This seems to me strictly less flexible, scalable, secure, easy to work with... I am having a hard time imagining why I would want to integrate with APIs or write an agentic harness in the database rather than in application code?

Maybe I'm behind the times but I don't understand.

It's similar to when we wrote all our business logic in eg pl/sql, stored procedures etc. Seems attractive at first, but it breaks separation of concerns, becomes difficult to test etc.