Reasoning trace

A reasoning trace is the actual written-out sequence of steps a model produces while working through a problem, the visible record of its thinking. In a chain-of-thought answer, the trace is the "23 minus 20 equals 3, plus 6 equals 9" part that comes before the final answer.

Traces are valuable for two reasons. They help the model itself, by serving as scratch paper, and they help us, because we can read the trace to understand why the model reached its answer and where it might have gone wrong.