Definition
Plain language
One round of asking a model a question and getting its reply back.
As stated in the literature
The standard single-request API shape where a list of role-labelled messages goes in and one assistant message comes out, as opposed to a multi-step agent loop that feeds outputs back as inputs.
Also called: chat completions
Why it matters: It is the basic unit almost all model use is built from, and knowing whether a system is doing one completion or looping many in a row tells you how much it can do on its own between human checks.
For example, typing "summarise this email" into a chatbox and getting a three-sentence summary back is a single chat completion.
Heard on the show
“Almost nobody runs these models as one-shot chat completions.”Episode 272 — How a Model Guesses Which Engine Is Running It, From a Wrong Date