SkillOpt: Microsoft Trained a Markdown File to 80.7 on SpreadsheetBench, Up From 41.8, Without Touching a Single Model Weight
The dominant assumption in agent improvement is that better agents require better models. More parameters, more RLHF, more fine-tuning. SkillOpt (microsoft/SkillOpt, MIT, 13k stars, arXiv:2605.23904) challenges this from the opposite direction: freeze the model entirely, and train the skill document the same way you would train a neural network, with rollout batches, minibatch reflection, bounded updates, a held-out validation gate, and epoch-wise regularization.
