Meta paper finds reinforcement learning post-training improves first-attempt success rate but reduces coverage across multiple attempts
A new Meta paper finds that reinforcement learning post-training makes agents perform better on first attempts, but fewer tasks can be solved within up to 128 attempts. The study tested 14 sets of base models and post-trained models on 3 agent benchmarks, and built the PTGS sampler, which raises temperature for difficult prompts and lowers it for easy prompts. On WebShop, the gemma-4-31B base model solved over 85% of tasks within 128 attempts, while the post-trained version solved 56%; the authors' proposed Sharpening Tax was positive in 36 of 42 model-benchmark combinations, meaning coverage shrank. The authors suggest that when selecting models for retryable agents, one should measure how many tasks the model can ultimately solve, rather than looking only at first-attempt accuracy.
A new Meta paper finds that reinforcement learning post-training makes agents perform better on first attempts, but fewer tasks can be solved within up to 128 attempts. The study tested 14 sets of base models and post-trained models on 3 agent benchmarks, and built the PTGS sampler, which raises temperature for difficult prompts and lowers it for easy prompts. On WebShop, the gemma-4-31B base model solved over 85% of tasks within 128 attempts, while the post-trained version solved 56%; the autho
Matched fieldsTitle、Summary、Body
