Interesting approach. It might be helpful to give the agent more tools though. Some simple aggregations might give it a notion of what's there to query for in the catalog. And a combination of overly broad queries and aggregations (terms, significant terms, etc.) might help it zoom in on interesting results. And of course, relatively large responses are not necessarily as much of a problem for LLMs as they would be for humans.

I agree, my post only scratches the surface. I want to give more knobs to the agent. But not so many that it can't really experiment / reason about them.