Ask HN: Good References on Agentic AI?

I have already delivered several projects based on RAG and generative AI. Part of the reason why I have been succesfull is that I started to document myself even before starting to sell and that has helped me both to manage expectations and select use cases that were a good fit for the technology. Now that the focus is shifting to Agentic AI I would like to follow the same approach and get up to speed. I am relying on the community to try to make my investigation faster. Who can suggest some good references on it? I am looking for material that is factual, covers the theoretical foundations and avoids any hype. I am fine with deeply technical material and scientific papers.