Editor Notes: (1) Incident ID date 09/10/2026 uses Anthropic's first public disclosure because no GTG-87001-specific event date was disclosed; the report covers activity from 12/2025–08/2026. (2) Anthropic said it banned associated accounts, shared threat intelligence with public- and private-sector partners, and strengthened safeguards. (3) On 09/11/2026, FT and AP connected the northern Yemen location to Houthi-controlled territory, but Anthropic did not identify the actors as Houthis.