Agents can self-improve without retraining.

EvoSkill v2 achieves this with persistent agent skills.

A coach agent reads the failed runs and writes the skill. The worker loads it the next time a similar task shows up.

No weights are touched. Every improvement comes from a simple file with lessons.

Every bad lesson also gets saved. On spreadsheet repair, the coach found the grader trusted cached values and wrote a skill telling the worker to skip recalculation.

Sentient's fix was to split the roles. The agent that writes skills cannot touch the test. A person reviews the results after every round.

With that in place, the hardest spreadsheet tasks went from 3 passes out of 120 to 21.