As of 2026-11-04
IFEval evaluates whether model responses satisfy automatically checkable natural-language constraints under the benchmark's instruction inventory.
Revision snapshot
Task and data. IFEval pairs roughly 500 prompts with one or more of 25 objectively verifiable instruction types such as length, formatting, keywords, and response structure.
Scoring. It reports strict and loose accuracy at prompt and instruction levels. Higher is better, but each of the four metrics is a separate result lineage.
What it measures. whether model responses satisfy automatically checkable natural-language constraints under the benchmark's instruction inventory.
Comparison rules. Compare the same metric level and strictness. Model responses were collected in different months, and the paper cautions that the two models differ greatly in size.
Access and licensing. The Compendium does not reproduce prompts or checker code; use the official paper and linked implementation under their stated terms.