The rules my research agents actually follow
Published:
The bug was one line of shell. The eval script found the last checkpoint with sort -t- -k2 -n, which splits a path on hyphens. The project lives in a folder called safety-decay, so the sort keyed on a field that never changed. It fell back to alphabetical order, where checkpoint-9372 comes after checkpoint-16875. The agent evaluated a checkpoint that was 55% of the way through training.