# Annotation span evaluation

Build-time release reference. Runtime readiness, deployment, payment settlement and external indexing are not evaluated here. Prices are proposed; this file cannot authorize execution or payment.

Evaluate supplied labeled text spans with exact boundaries or thresholded intersection-over-union. Bounded deterministic maximum-cardinality one-to-one matching returns precision/recall/F1, matches and unmatched IDs. UTF-16 half-open offsets are validated; labels and text meaning are not judged.

Release: 0.29.0. Built: 2026-10-06T15:38:00Z.

## Choose for
- evaluate named entity extraction annotation spans
- match predicted and reference text spans using exact offsets or iou
- calculate one-to-one span precision recall and unmatched evidence

## Outside this profile
- Semantic factuality or entailment checking
- Tokenization byte offsets or globally maximum total IoU matching

Proposed nominal USD 0.01 per successful call; payer fees excluded. No verified runtime availability.

- [Exact release contract](/reference/services/span-evaluate.json)
- [Input schema](/reference/schemas/span-evaluate.input.json)
- [Output schema](/reference/schemas/span-evaluate.output.json)
- [Fixed example](/reference/examples/span-evaluate.json)
- [Complete HTML reference](/discover/tools/span-evaluate)