Sergiu Nicoara
AI Engineer · Production LLM, RAG, and Agentic Systems
New to Contra
Sergiu is ready for their next project!
Most RAG systems fail not because of the model — but because
retrieval is broken.
Dense vector search alone misses exact matches. BM25 alone misses
semantic similarity. The fix: hybrid retrieval (dense + BM25 + RRF
fusion) with cross-encoder reranking on top.
Result on real...