Show HN: Vector databases are the wrong primitive for AI agents
1 points
2 hours ago
| 1 comment
| github.com
| HN
Hi HN,

We built ReasonDB because vector databases break down when agents need to reason over structured relationships.

ReasonDB combines: • knowledge graphs • reasoning queries • LLM-friendly APIs

Example:

agent.reason("Why did the refund fail?")

which traces relationships across events, policies and logs.

Repo: https://github.com/brainfish-ai/ReasonDB

Would love feedback.

ajainvivek
1 hour ago
[-]
Benchmark

We ran a small benchmark on a real-world insurance corpus: • 4 policy documents • ~1,900 hierarchical nodes • 100 queries across 6 complexity tiers

Comparing ReasonDB to a typical RAG pipeline (LangChain / LlamaIndex defaults):

Metric ReasonDB Typical RAG Pass rate 100% (12/12) 55–70% Context recall 90% avg 60–75% Median latency 6.1 s 15–45 s

The key difference is that ReasonDB performs BM25 candidate selection + LLM-guided traversal, rather than flat chunk similarity.

Example reasoning case

One query asked:

“What conditions define recurrent disability?”

The answer was split across two sections: • disability definition clause • policy schedule clause

Flat chunk retrieval returned only the first section.

ReasonDB followed the cross-reference extracted during ingestion, which raised recall from 67% → 100%.

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