Naive Single-Lineage Prompt Optimization Matches or Beats GEPA With Fewer Rollouts

arXiv 2608.27266·medium signalXBlueskyLinkedInCopy link

arXiv 2608.27266 pushes back on increasingly elaborate prompt optimizers with NPO, a lightweight single-lineage method that just iteratively revises a prompt using a teacher model and rollout feedback. NPO achieves comparable or better performance than GEPA with fewer rollouts, and its advantage widens with stronger teachers, suggesting teacher reasoning can substitute for optimizer-side search complexity; GRPO still wins on some interactive-game tasks less amenable to prompt optimization. NPO-optimized prompts also transfer verbatim to other student models, especially within the same family.