Fable 5 crushes nanoGPT speedrun, closing 81.7% of the gap to human record
NanoGPT Speedrun Frontier
Prime Intellect ran 153 autonomous runs across 18 frontier models on the nanoGPT optimizer speedrun. Fable 5, using Claude Code, achieved a record of 2,726, closing 81.7% of the gap to the human baseline of 2,600. The leaderboard shows Opus 5, Kimi K3, and GPT-5.6 Sol following, with detailed traces and equal-budget comparisons available.
We ran 153 autonomous runs across 18 frontier models on the nanoGPT optimizer speedrun.