IETF AI Preferences (AIPref)

In progress

Internet Engineering Task Force is working on a standardized preference signal for AI agents and crawlers ("building blocks that allow for the expression of preferences about how content is collected and processed for Artificial Intelligence (AI) model development, deployment, and use.")

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Website
datatracker.ietf.org/wg/aipref/about
Latest update
Apr 27, 2026 Vocabulary draft 06 updated
Primary approach
Preference signal

What it is

The AIPref effort investigates a standardized way to express preferences to AI systems, including crawlers and agents. The working group is iterating on vocabulary and attachment drafts; no production deployment signal is available yet.

Evidence trail

Examples

HTTP response header draft example Source

Active AIPref attachment work shows AI preferences delivered directly in the HTTP response.

HTTP/1.1 200 OK
Content-Type: text/plain
Content-Usage: train-ai=n
robots.txt draft example Source

The same attachment draft also sketches a domain-level robots.txt expression.

User-agent: *
Allow: /
Content-Usage: train-ai=n
HTML meta-tag draft example Source

Earlier vocabulary work also explored per-page HTML metadata for finer-grained preferences.

<meta name="AI-PREF" content="allow_training=false; retention_period=0">