On July 28, 1,134 employees of the leading AI labs — among them Anthropic CEO Dario Amodei, OpenAI chief scientist Jakub Pachocki, Meta chief scientist Shengjia Zhao and Google DeepMind safety lead Anca Dragan — published an open letter asking the US government to back an international effort to build the technical and governance tools needed to deliberately pace automated AI development. By the next day the count had passed 1,250 verified signatures. The signers stress they are not calling for a pause now — they want the ability to slow down to exist before it is needed.