Condé Nast

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Applications AI Preferences AI Preferences Automation Control Web Automation This document specifies a machine-readable protocol for server-side automation permissions in the light of recent advances in AI-driven web automation. Building upon RFC9309, this protocol addresses a broader range of state-changing activities that service owners may wish to control. It defines the file format, HTTP method restrictions, and purpose requirements. About This Document The latest revision of this draft can be found at . Status information for this document may be found at . Discussion of this document takes place on the AI Preferences Working Group mailing list (), which is archived at . Subscribe at .

Introduction The evolution of web automation has outpaced the capabilities of existing standards that only provide for read-only crawler permissions. Sophisticated, AI-driven bots are now able to interact with web servers in a complex, human-like manner, allowing them to deeply acquire and modify content. This document introduces a protocol that enables service owners to declare policies governing such interactions, notably state-changing HTTP methods.

Applicability The automation-preferences.txt file applies to automated systems interacting with web servers, especially those driven by AI models. Content owners may use this file to specify acceptable automation behaviors, and developers of automated systems may use these directives to ensure compliance.

Relationship to Extension Specification A separate document, "Protocol Extension for Automation Control," extends this document with additional directives and capabilities, focusing on a wider range of state-changing web requests. Implementations conforming to only this specification are considered compliant with the protocol. This protocol augments, and does not relax, the directives of . If a path is disallowed in robots.txt, an automation-preferences.txt directive MUST NOT be interpreted to expand access. Conversely, when robots.txt explicitly allows any HTTP method on a path, an automation-preferences.txt directive that disallows state-changing requests to that same path SHALL take precedence; the more restrictive rule MUST be enforced.

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 when, and only when, they appear in all capitals, as shown here. The following terms are used in this document:

• Automation: Programmatic interactions with a web server.
• State-changing requests: HTTP methods that alter server state (e.g., POST, PUT, DELETE, PATCH).
• Automation purpose: The declared intent or use case for which automation is being performed.

All terminology defined in this core specification applies to the extension specification without redefinition. The extension specification may introduce additional terms for concepts not covered in this document.

Protocol Specification

File Location and Format The automation-preferences.txt file MUST be hosted at the root of the domain, in the same manner as . The file is structured as a series of key-value pairs that specify automation permissions. The file MUST be served with the media type text/plain; charset=utf-8. Lines beginning with the hash symbol (#) are considered comments and MUST be ignored by parsers. Each directive consists of a field name, followed by a colon, followed by a value. Multiple values MAY be separated by commas. Parsers MUST silently ignore any directives they do not recognize. Implementations SHOULD reject files that contain raw control bytes (code points < U+0020) other than the permitted CR (U+000D) and LF (U+000A) line breaks.

HTTP Method Restrictions The protocol MUST explicitly list allowed HTTP methods using the allowed-methods directive. Typically, GET and HEAD are permitted while methods such as POST, PUT, DELETE, and PATCH are disallowed for automated processing. Methods that are not listed are assumed to be disallowed. Example:

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If a group omits the allowed-methods directive, all HTTP methods are considered disallowed for automated processing within that scope.

Purpose Declaration The protocol allows server owners to accept or reject user agents with specific purposes with the allowed-purposes directive, which accepts a comma-separated list of permitted purposes using standardized vocabulary terms. The specific vocabulary terms for automation purposes are not defined in this document. Instead, this protocol provides a mechanism for expressing allowed and disallowed purposes, which can be compatible with an accepted vocabulary standard in the future. Example:

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Scope and Applicability The automation-preferences.txt file is divided into groups, each of which applies to a specific subset of content. Each group begins with one or more scope directives that define the target of the preferences. The following directives MAY be used within a group:

• scope: Specifies the URL pattern (e.g., /admin/) to which the group applies. Wildcards MAY be used to indicate variable components of the URL.
• host: Specifies a subdomain or host. If present, the group applies only to the indicated subdomain; if omitted, the group is assumed to apply to the entire host.
• user-agent: Specifies one or more automation user-agent tokens to which the group applies. If omitted, the group applies to all user agents.

Groups are processed in order of specificity. Specificity is determined by (1) an exact host match over a wildcard or absent host; (2) the longest matching scope directive; (3) the most specific user-agent token (an exact token outranks the wildcard *); then (4) appearance order, where the group appearing later in the file SHALL take precedence when all preceding criteria are equal. A group MUST contain at least one scope directive and MAY omit all other directives. Example:

user-agent: * host: example.com scope: / allowed-methods: GET, HEAD user-agent: * host: example.com scope: /admin/ allowed-methods: GET ]]>

Formal Syntax Below is an Augmented Backus-Naur Form (ABNF) description, as defined in , with references to , , and . automation-preferences = *( group ) group = 1*scope-directive ; at least one <scope> *( directive / emptyline ) 1*emptyline ; blank line terminates group directive = scope-directive / host-directive / user-agent-directive / method-directive / purpose-directive ; --- individual directives ---------------------------------- scope-directive = *WS "scope" *WS ":" *WS url-pattern EOL host-directive = *WS "host" *WS ":" *WS host-pattern EOL method-directive = *WS "allowed-methods" *WS ":" *WS method-list EOL purpose-directive = *WS "allowed-purposes" *WS ":" *WS purpose-list EOL user-agent-directive = *WS "user-agent" *WS ":" *WS product-token *( *WS "," *WS product-token ) EOL ; --- directive value syntax --------------------------------- ; url-pattern: visible ASCII or UTF-8, implementers SHOULD interpret it ; as an RFC 3986 path/authority matcher with wildcards url-pattern = 1*( VCHAR / UTF8-char-noctl ) ; host-pattern: UTF-8 hostname or wildcard; servers SHOULD match IDNA U-labels host-pattern = 1*( ALPHA / DIGIT / "-" / "." / UTF8-char-noctl ) method-list = method *( *WS "," *WS method ) method = "GET" / "HEAD" / "POST" / "PUT" / "DELETE" / "PATCH" / "OPTIONS" / "TRACE" / "CONNECT" purpose-list = purpose-token *( *WS "," *WS purpose-token ) purpose-token = 1*VCHAR ; placeholder for future vocabulary ; product-token: derived from RFC 9309 product-token = identifier / "*" identifier = 1*( %x2D / %x41-5A / %x5F / %x61-7A ) ; --- lexical primitives ------------------------------------- comment = "#" *( UTF8-char-noctl / WS / "#" ) emptyline = *WS [comment] EOL EOL = *WS [comment] NL NL = CRLF / LF / CR CRLF = CR LF CR = %x0D LF = %x0A WS = SP / HTAB SP = %x20 HTAB = %x09 ; --- core ABNF terminals (RFC 5234) -------------------------- ALPHA = %x41-5A / %x61-7A DIGIT = %x30-39 VCHAR = %x21-7E ; --- UTF-8 (derived from RFC 3629) --------------------------- UTF8-char-noctl = UTF8-1-noctl / UTF8-2 / UTF8-3 / UTF8-4 UTF8-1-noctl = %x21 / %x22 / %x24-7F UTF8-2 = %xC2-DF UTF8-tail UTF8-3 = %xE0 %xA0-BF UTF8-tail / %xE1-EC UTF8-tail-2 / %xED %x80-9F UTF8-tail / %xEE-EF UTF8-tail-2 UTF8-4 = %xF0 %x90-BF UTF8-tail-2 / %xF1-F3 UTF8-tail-3 / %xF4 %x80-8F UTF8-tail-2 UTF8-tail = %x80-BF UTF8-tail-2 = UTF8-tail UTF8-tail UTF8-tail-3 = UTF8-tail UTF8-tail UTF8-tail

Extension Mechanism The automation-preferences.txt file defines a forward-compatible approach where implementations:

• MUST process all recognized directives according to this specification
• MUST silently ignore any unrecognized directives
• MUST NOT fail or produce errors when encountering extended directives

This enables future extensions to add new capabilities, which may include:

• Rate limiting controls
• Automation technology restrictions
• API and XHR permissions
• Session requirements
• Asset-level annotation methods

Implementation and Enforcement Servers implementing this protocol SHOULD:

• Verify incoming requests against automation-preferences.txt.
• Respond with appropriate HTTP status codes (e.g., 403 Forbidden) for non-compliant requests.

Clients consuming this protocol SHOULD:

• Fetch and parse automation-preferences.txt before performing automated operations.
• Honor the HTTP method restrictions specified.
• Declare their automation purpose.
• Respect the scope directives when performing operations on different paths.

Implementations MAY cache automation-preferences.txt in accordance with ; all freshness calculations are governed solely by standard HTTP cache-control semantics.

Security Considerations The use of automation-preferences.txt introduces security considerations that SHOULD be assessed by implementors:

• Parsing of automation-preferences.txt MUST be performed securely to prevent vulnerabilities such as buffer overruns and denial-of-service attacks.
• Care SHOULD be taken to avoid exposing sensitive scope details that could be exploited by adversaries.
• The protocol does not provide authentication or cryptographic verification mechanisms for the file content. Servers SHOULD ensure the file is served via secure connections to prevent tampering.
• The protocol does not enforce client compliance; it relies on good-faith adherence by automation providers. Servers SHOULD implement additional detection and enforcement mechanisms when needed.

IANA Considerations This document has no IANA actions.

References Normative References Harvard University Huawei Technologies Informative References

Sample automation-preferences.txt File The following is an example of an automation-preferences.txt file that adheres to this specification:

scope: / user-agent: * host: example.com allowed-methods: GET, HEAD allowed-purposes: PLACEHOLDER_PURPOSE1, PLACEHOLDER_PURPOSE2 scope: /admin/ user-agent: ExampleBot host: example.com allowed-methods: GET allowed-purposes: PLACEHOLDER_PURPOSE1 ]]>