Definition
Plain language
Extra text a model writes to itself while working out an answer before replying.
As stated in the literature
Intermediate chain-of-thought output emitted at test time; functionally lets the model iterate over candidates and apply a rule serially, recovering much of the authoring gap.
Also called: reasoning tokens
Why it matters: These intermediate steps let a model walk through candidates one at a time instead of guessing a whole set at once, which recovers much of the accuracy it otherwise loses.
For example, before answering "which of these ten numbers are prime," the model writes out a short check for each number in turn, then gives its final list.
Heard on the show
“You get billed for reasoning tokens, so the API tells you how many the source model generated.”Episode 238 — How a Cheap Model Reads the Flagship's Secret Reasoning Aloud