AI Preferences K. Kelley Internet-Draft Anthropic Intended status: Standards Track 30 October 2026 Expires: 3 May 2027 Machine-Readable Training Preference Signal draft-kelley-aipref-training-preference-signal-00 Abstract This document describes how a service operator binds usage preferences (e.g., "no AI training") to paths by writing ordinary robots.txt groups keyed by a per-purpose policy token in the User- Agent line. It introduces no new directive names and no new grammar: the path language, longest-match precedence, and group structure of robots.txt are not changed. About This Document This note is to be removed before publishing as an RFC. Status information for this document may be found at https://datatracker.ietf.org/doc/draft-kelley-aipref-training- preference-signal/. Discussion of this document takes place on the AI Preferences Working Group mailing list (mailto:ai-control@ietf.org), which is archived at https://mailarchive.ietf.org/arch/browse/ai-control/. Subscribe at https://www.ietf.org/mailman/listinfo/ai-control/. Status of This Memo This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at https://datatracker.ietf.org/drafts/current/. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." This Internet-Draft will expire on 3 May 2027. Kelley Expires 3 May 2027 [Page 1] Internet-Draft Training Preference Signal October 2026 Copyright Notice Copyright (c) 2026 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (https://trustee.ietf.org/ license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Revised BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Revised BSD License. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1.1. Goals . . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Conventions and Definitions . . . . . . . . . . . . . . . . . 3 3. Vocabulary . . . . . . . . . . . . . . . . . . . . . . . . . 4 4. Design . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 4.1. The Policy Token . . . . . . . . . . . . . . . . . . . . 5 4.2. Checking for Preferences . . . . . . . . . . . . . . . . 5 4.3. Independence from Crawler Rules . . . . . . . . . . . . . 6 4.4. Effects on Crawling Behavior . . . . . . . . . . . . . . 6 4.5. Precedence . . . . . . . . . . . . . . . . . . . . . . . 6 5. Security Considerations . . . . . . . . . . . . . . . . . . . 6 6. Privacy Considerations . . . . . . . . . . . . . . . . . . . 6 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6 8. References . . . . . . . . . . . . . . . . . . . . . . . . . 7 8.1. Normative References . . . . . . . . . . . . . . . . . . 7 8.2. Informative References . . . . . . . . . . . . . . . . . 7 Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 7 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 10 1. Introduction A service operator binds usage preferences (e.g., "no AI training") to paths by writing ordinary robots.txt groups keyed by a per-purpose *policy token* in the User-Agent line. User-Agent: __usage_ai-training Disallow: / Allow: /press-kit/ Figure 1: A policy-token group Kelley Expires 3 May 2027 [Page 2] Internet-Draft Training Preference Signal October 2026 This expresses a preference _against_ AI training for all paths except those under /press-kit/, for which it expresses a preference _in favor_ (Section 4.2). This document introduces no new directive names and no new grammar; the path language, longest-match precedence, and group structure defined by [ROBOTS] are not changed. As a result, the wide variety of existing parsers deployed across the Internet will continue to interpret traffic management signals as they did previously, and will ignore policy-token groups as they would any group for a user agent they do not recognize. 1.1. Goals 1. *Path-specific bindings.* Preferences can be expressed per path, and not only site-wide (Section 4.2). 2. *Minimal distance from RFC 9309.* Semantics, and ideally syntax, stay as close to [ROBOTS] as possible, so that authors and implementers can use the mental model they already have. 3. *No large-scale duplication.* robots.txt files are size- constrained (Section 2.5 of [ROBOTS]), and some deployed files already contain heavily duplicated groups. Expressing preferences does not require restating existing rules (Section 4.1). 4. *Unchanged legacy behavior.* A parser or consumer that does not implement this mechanism behaves as before. This holds for parsers that are actually deployed, not only for idealized RFC 9309 parsers. Conversely, implementations treat files that do not use this mechanism exactly as before (Section 4.2 and Section 4.3). 5. *Consistent interpretation across consumers.* This mechanism does not depend on the divergent parts of deployed parser behavior (Section 4.1). 2. Conventions and Definitions The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all capitals, as shown here. service operator: An entity that operates an HTTP service, such as a Kelley Expires 3 May 2027 [Page 3] Internet-Draft Training Preference Signal October 2026 website, and publishes a robots.txt file for it. For preferences expressed through this mechanism, the service operator is the "declaring party" (Section 2 of [VOCAB]). [ROBOTS] calls this party a "service owner". consumer: An entity that interprets preference signals that a service operator expresses through the mechanism defined in this document. parser: In the sense of [ROBOTS]; software that parses robots.txt files and matches product tokens and paths against their rules. policy token: A product token (Section 2.2.1 of [ROBOTS]) whose RFC 9309 signals a consumer uses to determine how content will be used. A policy token need not appear in the User-Agent header field (Section 10.1.5 of [HTTP]) of any outbound request. This document introduces a new, cross-vendor policy token (Section 4.1). proprietary policy token: A policy token documented by a single consumer. Some service operators already include these in their robots.txt files. 3. Vocabulary The __usage_ai-training policy token corresponds to the definition that the IETF aipref Working Group has arrived at (Section 4.1 of [VOCAB]). The following definitions are quoted from that document: AI Training: Using an asset to modify the learned parameters of a generative AI model. The training of models that are used to perform exclusively non- generative tasks is not included in this category, even if the model is capable of generative tasks. Generative AI model: An AI model that is used to generate synthetic content in one or more modalities. Alternatively, an AI model that is made available for use to generate synthetic content in one or more modalities. This definition does not include a model that is used, or made available for use, for classification, ranking, or scoring, even where the model generates rationale for its output. This document applies those definitions as follows: asset: The content retrieved from a path. The preferences that Kelley Expires 3 May 2027 [Page 4] Internet-Draft Training Preference Signal October 2026 apply to an asset are those expressed in the robots.txt file in effect when the asset was retrieved (Section 2.4 of [ROBOTS]; see also [ATTACH]). This document does not define a parallel vocabulary; it tracks the work of the aipref Working Group. Implementers SHOULD consider updating their definitions, and adding or removing vocabulary terms, as the aipref Working Group reaches consensus in additional areas. 4. Design 4.1. The Policy Token This document defines the policy token __usage_ai-training. The policy token conforms to the product-token syntax in Section 2.2.1 of [ROBOTS] (letters, _, -). Consumers MUST match policy tokens exactly, apart from case, as for any product token. (Note that some deployed parsers match more flexibly; the __ prefix makes accidental matches unlikely.) A single group MAY name several policy tokens (consecutive User-Agent lines; Section 2.2 of [ROBOTS]) to bind its rules to several purposes. Policy tokens and other product tokens MAY be mixed in a group. 4.2. Checking for Preferences To determine whether a preference has been expressed for a given path, a consumer looks up the path and policy-token combination as specified in Sections 2.2.1 and 2.2.2 of [ROBOTS]. However, wildcard groups (i.e., User-Agent: *) MUST NOT be interpreted as matching the policy token. If the lookup finds that the path is disallowed, a preference against the use described by the policy token has been expressed for that path. If it finds that the path is allowed, a preference in favor of that use has been expressed. If no group contains the __usage_ai-training policy token (i.e., there is no User-Agent: __usage_ai-training line in the file), then no preference has been expressed. If such a file contains a proprietary policy token, consumers SHOULD interpret that token as they would in the absence of this document, but MUST NOT treat it as expressing a preference in the context of this document (see Section 4.5). Kelley Expires 3 May 2027 [Page 5] Internet-Draft Training Preference Signal October 2026 4.3. Independence from Crawler Rules Consumers MUST interpret the RFC 9309 signals being expressed based on their own product token(s) exactly as they would in the absence of this document. That is, ExampleBot still checks whether there are rules for ExampleBot; if there are, they still express the service operator's preference about crawling. Nothing in this document changes that signaling. Content-usage preferences and traffic management signals can both be expressed in robots.txt, but they are independent and orthogonal. 4.4. Effects on Crawling Behavior This policy token is not a directive for crawling behavior. A consumer MAY use preferences to inform crawling. For example, if it crawls only for purposes covered by the policy token, it MAY refrain from retrieving resources for which a preference against those purposes has been expressed. If a service operator wishes to limit crawling, it MAY use groups for crawlers' product tokens in robots.txt to do so. 4.5. Precedence Specific expressions SHOULD take precedence over general ones. Consumers MAY document that they interpret rules that match proprietary policy tokens as being more specific than the __usage_ai- training policy token. Private agreements MAY override preferences expressed via this mechanism. 5. Security Considerations The security considerations of Section 3 of [ROBOTS] apply to this mechanism. 6. Privacy Considerations This document does not introduce any new privacy considerations. 7. IANA Considerations This document has no IANA actions. Kelley Expires 3 May 2027 [Page 6] Internet-Draft Training Preference Signal October 2026 8. References 8.1. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, . [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, May 2017, . [ROBOTS] Koster, M., Illyes, G., Zeller, H., and L. Sassman, "Robots Exclusion Protocol", RFC 9309, DOI 10.17487/RFC9309, September 2022, . [VOCAB] Keller, P. and M. Thomson, "A Vocabulary For Expressing AI Usage Preferences", Work in Progress, Internet-Draft, draft-ietf-aipref-vocab-08, 13 September 2026, . 8.2. Informative References [ATTACH] Illyes, G. and M. Thomson, "Associating AI Usage Preferences with Content in HTTP", Work in Progress, Internet-Draft, draft-ietf-aipref-attach-05, 18 August 2026, . [HTTP] Fielding, R., Ed., Nottingham, M., Ed., and J. Reschke, Ed., "HTTP Semantics", STD 97, RFC 9110, DOI 10.17487/RFC9110, June 2022, . Acknowledgments The author is grateful to the Working Group's chairs, Mark Nottingham (Cloudflare) and Suresh Krishnan (Cisco), to the editors of the vocabulary draft, Martin Thomson (Mozilla) and Paul Keller (Open Future), and to the responsible Area Director, Mike Bishop (Akamai), whose incredible effort to facilitate discussion and endless patience (in addition to their own individual contributions) have made the Working Group's progress possible. Kelley Expires 3 May 2027 [Page 7] Internet-Draft Training Preference Signal October 2026 The author also thanks the following people for their substantial contributions to shaping the Working Group's discussion and for their partnership. Affiliations are listed for identification only, since IETF participants contribute as individuals. +======================+=====================================+ | Name | Affiliation | +======================+=====================================+ | Farzaneh Badiei | Digital Medusa | +----------------------+-------------------------------------+ | Lila Bailey | Internet Archive | +----------------------+-------------------------------------+ | Kevin Bankston | Center for Democracy and Technology | +----------------------+-------------------------------------+ | Fabrice Canel | Microsoft | +----------------------+-------------------------------------+ | Alissa Cooper | Knight-Georgetown Institute | +----------------------+-------------------------------------+ | Sonia Cooper | Microsoft | +----------------------+-------------------------------------+ | Glenn Deen | Comcast NBCUniversal | +----------------------+-------------------------------------+ | Caleb Donaldson | Google | +----------------------+-------------------------------------+ | Daniel Etcovitch | Anthropic | +----------------------+-------------------------------------+ | Christopher Flammang | Elsevier | +----------------------+-------------------------------------+ | Max Gendler | News Corp | +----------------------+-------------------------------------+ | Alex Gibson | News Corp | +----------------------+-------------------------------------+ | Jordan Gimbel | Microsoft | +----------------------+-------------------------------------+ | Mark Gray | OpenAI | +----------------------+-------------------------------------+ | Nate Hake | Travel Lemming | +----------------------+-------------------------------------+ | Gary Illyes | Google | +----------------------+-------------------------------------+ | Meredith Jacob | American University Washington | | | College of Law | +----------------------+-------------------------------------+ | Mirja Kühlewind | Ericsson | +----------------------+-------------------------------------+ | Laurent Le Meur | EDRLab | +----------------------+-------------------------------------+ | Jo Levy | Norton Law | Kelley Expires 3 May 2027 [Page 8] Internet-Draft Training Preference Signal October 2026 +----------------------+-------------------------------------+ | Greg Lindahl | Common Crawl Foundation | +----------------------+-------------------------------------+ | Krishna Madhavan | Microsoft | +----------------------+-------------------------------------+ | Sarah McKenna | Sequentum | +----------------------+-------------------------------------+ | Angela Mills Wade | European Publishers Council | +----------------------+-------------------------------------+ | John Mueller | Google | +----------------------+-------------------------------------+ | Chris Needham | BBC | +----------------------+-------------------------------------+ | Elaine Newton | Amazon Web Services | +----------------------+-------------------------------------+ | Victoria Noble | Electronic Frontier Foundation | +----------------------+-------------------------------------+ | Sebastian Posth | Liccium | +----------------------+-------------------------------------+ | Brendan Quinn | IPTC | +----------------------+-------------------------------------+ | Courtney Radsch | Open Markets Institute | +----------------------+-------------------------------------+ | Felix Reda | GitHub | +----------------------+-------------------------------------+ | Eric Rescorla | Independent | +----------------------+-------------------------------------+ | Matt Rogerson | Financial Times | +----------------------+-------------------------------------+ | Leah Romm | Cloudflare | +----------------------+-------------------------------------+ | Leonard Rosenthol | Adobe | +----------------------+-------------------------------------+ | Malikat Rufai | Meta | +----------------------+-------------------------------------+ | Achim Schlosser | Bertelsmann | +----------------------+-------------------------------------+ | Rony Shalit | Bright Data | +----------------------+-------------------------------------+ | Bradley Silver | Advance | +----------------------+-------------------------------------+ | Erin Simon | Google | +----------------------+-------------------------------------+ | Esther Tetruashvily | OpenAI | +----------------------+-------------------------------------+ | Michael Tremante | Cloudflare | +----------------------+-------------------------------------+ | Thom Vaughan | Common Crawl Foundation | Kelley Expires 3 May 2027 [Page 9] Internet-Draft Training Preference Signal October 2026 +----------------------+-------------------------------------+ | James Whymark | Meta | +----------------------+-------------------------------------+ | Timid Robot Zehta | Creative Commons | +----------------------+-------------------------------------+ Table 1 Many more people shaped the Working Group's discussion than appear above, and this list has almost certainly left out someone who belongs on it. Any such omission is inadvertent, and the author apologizes in advance. Author's Address Kevin Kelley Anthropic Email: kelleyk-ietf@kelleyk.net Kelley Expires 3 May 2027 [Page 10]