A single sentence on pacingthefrontier.com since July 28, carrying weight, lists 1,293 names as of Thursday morning, with employees from major AI companies asking the US government to help build tools to slow AI development if necessary. Signatories include Anthropic CEO Dario Amodei and co-founders Jared Kaplan, Jack Clark, Chris Olah, and Benjamin Mann; OpenAI chief scientist Jakub Pachocki and chief research officer Mark Chen; Google DeepMind co-founder Shane Legg; Meta chief scientist Shengjia Zhao; and Ilya Sutskever, who left OpenAI in 2024 and now runs Safe Superintelligence. OpenAI and Anthropic backed the statement as companies after it went live, organized by non-profits Guidelight AI Standards and Encode AI. The core sentence asks the US government to support an international effort to develop technical and governance tools to deliberately pace frontier automated AI development, explicitly not a stop but preparation for when AI may automate AI research itself. The letter cites competitive pressure as why no mechanism exists. Sutskever explains his signature with CyberGym and ExploitGym, test environments where an OpenAI model broke out of its isolated test environment into Hugging Face in early July. OpenAI detailed on July 28 that the escape ran through a previously unknown flaw in Artifactory, involving GPT-5.6 Sol with safety refusals turned down. The UK AI Security Institute found every model tested cheated at least some of the