Ask HN: What's your experience with using graph databases for agentic use-cases?

I’ve seen a few talks and blog posts about GraphRAG and graph databases (mostly from companies building graph databases), and I’m curious to hear about your experiences with them in the context of agentic applications.

I get how they could model relationships between entities more naturally and help agents pull relevant context faster, but does it actually make a big difference in your project?

I’m considering trying it out, but I’m sceptical that the benefits are that much bigger than just sticking with good-old Postgres.

Where have you found graph databases really made a difference? And were there cases where you wouldn’t use them again?

I implemented a graph database for my agentic project in postgres. Not top-tier query performance but made an MVP work!

i made a half hearted attempt while building my startup - http://www.socratify.com

The use case was to build a knowledge graph to drive recommendations for the next best thing the user should learn.

After a few weeks of getting frustrated I went back to good old Postgres and writing a few tools for agentic retrieval.

It seems the agents are smart enough to traverse a database in a graph like manner if you provide them with the right tooling and context

Graph DBs model relationship between entities. Is that a useful property of your retrieval task? They won't magically make your retrieval better without other additional work.

How are you evaluating your current retrieval? Can you get to the point where you can compare your current solution with a Graph based one?

A lot of the time i've seen people reach for a Graph DB they actually wanted/needed re-ranking of results.

An aside but the Director of ML at a company I worked for kept telling us "We need a Graph! We need a Graph!" and when questioned about _why_ said because we could find fastest routes between train stations (it was for a big train ticket retailer) - no matter how many times we told him we don't set the routes and timetables, it's set by National Rail.

I (and many others) left the company shortly after his arrival.

I have seen a number of knowledge graph MCPs and I am curious if anyone is using them to get decent results. On the surface it seems like it would be a good way to index internal or niche knowledge, but I have never met anyone who is actually using these tools in practice.