GitHub's decision to pause sign-ups is a structural confession that its cost assumptions were built for autocomplete, not agents. The company acknowledged that agent workflows consume resources at a rate that — a problem GitHub described with unusual transparency for a major platform. The economics broke before the product did, and the sign-up freeze makes that sequence public. The developers who built workflows around Copilot agent features are now inside a tool whose operator has admitted the unit economics do not work — that…