Mumsnet's AI prompt for writing forum posts appears in public thread, sparking denial and user revolt
Published · updated · curated by AI Is Going Just Great
Source: theguardian.com ↗
"Mumsnet works because the people on it are real. Members trust that the advice they get comes from other parents, not a machine."
A user on Mumsnet asking for a "sanity check" about a family dispute involving a neurodivergent uncle got back something unexpected: a raw AI prompt titled AIBU Response Schema v.1.0, complete with instructions to write an "interpersonal reasonableness" post, definitions of Mumsnet abbreviations, and directives not to "imply a sick child owes social performance." The prompt was meant to stay hidden. It did not.
Mumsnet offered three successive explanations: the prompt came from a title-suggestion tool using an OpenAI model; then it came from the user's own computer; then founder Justine Roberts confirmed it came from Mumsnet's systems after all, describing it as an error on OpenAI's side. Users were unconvinced at each stage, and some copy-pasted the prompt into an AI chatbot to confirm it produced a full forum reply. The incident arrived against an already uncomfortable backdrop: Mumsnet's monthly unique users fell 19% in 2025 to 6.1 million, and the site's own annual report had flagged that it was "embedding AI tools to improve productivity and enhance the user experience."