New best on PostTrainBench: Fable 5.1 (Max) · Claude Code (44.6%)
The loop: AI agents perform post-training on a base model to improve its benchmark average. The resulting model is evaluated on a benchmark specifically designed to measure AI driven engineering tasks.
Claude Code achieved a new high score of 44.6% on PostTrainBench by successfully post-training a base model.





![Image: lesswrong.com The Chain Lens [interim]](/media/r-cca9717349b6fefe.webp?v=1794464581)
