[SlipperySlope]

An agent framework I built for my AI research has exactly that.

I use an additional message parameter, automatically inserted and maintained by the framework, which is a list of the messages (FIPA style operation + parameters) from the originating agent forwards to the point of debugging. This gets voluminous and is gated by debug levels.

[Diederich]

Same here. The framework I've been building over and over for various companies for the past 20 years has extensive debugging capabilities. With the right 'messages all the way down' mindset, it gets extremely powerful.