# AIPREF Content-Usage

The IETF's standards-track vocabulary for stating how content may be used by AI systems.

**[Access](/docs/access)** · watched, not scored

It is the one opt-out mechanism on a path to becoming an actual internet standard, which is what Content Signals and ai.txt are not. The half that defines the crawl-detectable surface, a Content-Usage header and robots.txt rule, has lapsed.

## Why we do not score it

We will score it when the `attach` draft reaches RFC. The `vocab` half advancing does not move that condition: only `attach` defines the header and robots.txt rule a crawl could read.

## Adoption

**Specification only** (L0)

A published specification or draft. Deployments are limited to the authors' own demos. Direction of travel: ► flat, as of 2026-08-22.

Drafts only, with no deployment. `vocab` reached -06 on 2026-08-14, while `attach`, the half that defines the readable surface, is still lapsed at -04 from 2025-10-28.

## Specifications

| Document | Revision | Kind |
|---|---|---|
| [IETF AIPREF working group](https://datatracker.ietf.org/wg/aipref/about/) | living document | guidance |
| [draft-ietf-aipref-attach (the Content-Usage header and robots.txt rule)](https://datatracker.ietf.org/doc/html/draft-ietf-aipref-attach) | -04, lapsed 2025-10-28 | specification |
| [draft-ietf-aipref-vocab (the usage vocabulary)](https://datatracker.ietf.org/doc/html/draft-ietf-aipref-vocab) | -06, 2026-08-14 | specification |

Last re-read against the published documents: 2026-08-22.