Four Tech Giants, on the Same Day, Wrote Websites a One-Line Refusal
On October 30, 2026, four companies jointly backed a shared policy token, __usage_ai-training: a website writes it once in robots.txt to express refusal of generative AI training.
- 01THE DRAFT — On October 30, 2026, Kevin Kelley submitted the individual draft to the IETF.
- 02THE TOKEN — The token is named __usage_ai-training and written in robots.txt.
- 03THE SPLIT — Anthropic has begun; Microsoft set February 1, 2027; Google targets 2027.
WHAT HAPPENEDWhat Happened
The signal is written very briefly. A website adds "User-Agent: __usage_ai-training" in robots.txt, followed by "Disallow: /", and can use Allow rules to carve out exceptions for individual paths. The token comes from an IETF individual draft submitted by Anthropic standards lead Kevin Kelley, titled Machine-Readable Training Preference Signal, also dated October 30, 2026.
The four companies' implementation timelines differ. Anthropic says it has begun implementing, OpenAI says it will implement within the coming months, Microsoft set February 1, 2027 for phased effect by crawl, and Google only says its target is 2027. Microsoft also offers separate controls for training and grounding; grounding means a model citing live web content when answering, not training weights.
The signal has two hard boundaries. First, it governs only generative AI training and does not change ordinary search indexing, as both Google and Microsoft have stated explicitly. Second, it is not a formal standard: an individual draft carries no IETF endorsement and will need revision or adoption before it expires on May 3, 2027. Content already collected into datasets or trained into models will not be deleted because a new line was written.
ONE TOKEN, FOUR READERSOne Standard Format Solves Repeated Labor
Until now, websites had to write rules company by company: GPTBot, ClaudeBot and Google-Extended each had their own names. Now a single token can be understood identically by four companies, and a webmaster's workload falls from four files to one.
The price of unification is waiting. Writing the token into a file does not make it effective immediately; real effect depends on each company's crawling and implementation progress, and the old per-company rules remain useful during the transition.
THE MISSING SIGNATUREMeta's Missing Signature Is This Round's Biggest Gap
Meta publicly welcomed the idea of a unified signal but did not confirm its crawlers will honor it. With one of the world's largest content platforms absent from the commitment list, the unified signal's coverage is discounted.
For publishers, the signal's value depends on whether the absentees follow. If Meta stays out for long, websites will still need to keep a separate set of rules for it.
NO RETROACTIVE DELETERefusing Training Does Not Mean Deleting History
The signal expresses only future training preferences. Data already collected and models already trained fall outside its jurisdiction, and publishers cannot use it to claw back historical use.
Litigation continues in parallel. The Indian publishers' suit against OpenAI is part of that backdrop; a technical signal solves a process problem, not a rights-ownership problem.
THE SHIFTWhat Changed
SIGNAL JUDGMENT — ANALYSISThe Unified Signal Is Worth Writing, but Do Not Expect It to Work at Once
Tokenta Signal's judgment is unchanged: websites should add the line now; it costs one line. What decides whether it works is the pace of crawl implementation and whether the absentees follow, and both need to be rechecked monthly.
WHAT REMAINS UNCERTAINWhat Remains Uncertain
EVIDENCEEvidence
Key points confirmed from the original report: on October 30, 2026, four companies jointly backed the shared token named __usage_ai-training; Anthropic has begun implementing, OpenAI within the coming months, Microsoft from February 1, 2027, and Google targets 2027.
PRIMARY SOURCESPrimary Sources
- AI Weekly: OpenAI, Google, Microsoft, Anthropic Back One AI Opt-Out Token
https://aiweekly.co/alerts/openai-google-microsoft-anthropic-back-one-ai-opt-out-token - PPC Land: Google, Microsoft, OpenAI and Anthropic back one AI training opt-out
https://ppc.land/google-microsoft-openai-and-anthropic-back-one-ai-training-opt-out/
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