Jo Kristian Bergum

Jo Kristian Bergum

Hornet.dev

Jo Kristian Bergum is the CEO of HORNET.dev and a 25-year veteran of the search industry, formerly serving as the Chief Scientist at Vespa.ai and a Distinguished Engineer at Yahoo.

Sessions

The unreasonable effectiveness of BM25 for agentic search

Talk
15. September 2026, 14:15 - 15:00
Main Stage
GPT-5 is shockingly good at search, and that changes the "BM25 as a baseline" story. Using GPT-5 search trajectories from BrowseComp-Plus, I'll show how default BM25 parameters and evaluation harnesses can make lexical retrieval look weak, while real agent queries often play directly to BM25's strengths.