Anthropic announced in a detailed report this week that it had investigated and disrupted “threat actors” who used its AI software for military purposes. One of them was in Yemen, in Houthi-held territory. In the report titled Detecting and Countering Misuse of AI, Anthropic described an ambitious weapons development effort in northern Yemen, where a group was working on three sophisticated missile projects simultaneously.Iran-backed Houthis use the capital Sanaa and northern Yemen, which they control, as a launch pad for attacks against neighbours. On Thursday, the rebels seized the strategic port city of Mokha on the western coast, further expanding their control along the Red Sea and near the Bab Al Mandeb shipping route.The report provided astonishing detail about the group’s work, offering a rare glimpse into the scale and sophistication of its weapons ambitions.One involved turning commercially available technology into a guided rocket, using an off-the-shelf, phone-grade flight computer and a homing system designed to steer it towards its target during the final phase of flight.A second project was far more ambitious: a multistage ballistic missile that the group said it wanted to send across more than 2,000km.The most striking, however, was called the R2000 programme, a family of proposed missile variants that included a hypersonic glide vehicle, a technology normally associated with some of the world’s most advanced military powers.“The activity took place between December 2025 and August 2026, involved Claude Haiku, Sonnet and Opus models, and was disrupted by Anthropic, which banned the accounts and published the case in the report,” the company said.Houthi rebels conduct military exercises in Saada, northern Yemen. Photo: SabaShow caption: Houthi rebels conduct military exercises in Saada, northern …According to Anthropic, rather than hire software engineers, the actors used Claude Code to write the guidance, navigation and control software that keeps a vehicle steady and on course. They also organised the work as a team. Several Claude instances ran in parallel with assigned roles: one wrote code, one did research and a third reviewed what the first produced, with the humans acting as the leads, handing out tasks.Anthropic's safeguards refused many of these requests, though not all, according to the report. The group worked around them by concealing what they were building and what the software was for, and by breaking the work into separate sessions so no single conversation exposed the whole picture.They never got to a working weapon, as far as Anthropic could tell, but they did test-fire a guided rocket. It appears to have failed; within hours, they were back with Claude trying to diagnose what went wrong.Anthropic found the activity through its own investigations into suspected weapons development, banned the accounts, and passed threat information to government and industry partners. However, the group had already built an offline simulation toolkit that runs without Claude or commercial tools like MATLAB, so some of its capabilities survived the ban.The company's decision to release the report comes after several high-profile incidents related to AI models led to concern about whether they were becoming too powerful and posing a risk to public safety.Over the past decade, the Houthis have slowly transformed from a local armed faction into a wider force, threatening neighbouring countries and attacking shipping lanes while consolidating control over Sanaa and north-west Yemen.The Houthis have an estimated troop strength, according to the US-based Middle East Institute, of 350,000, including child soldiers, forced-conscript African refugees and foreign mercenaries.The rebels rely primarily on cross-border smuggling networks and complex maritime supply routes that extend across the Arabian Sea, the Gulf of Aden and the Red Sea to secure a significant portion of their military and logistical needs, including weapons, drone components, ballistic missiles, and technology and equipment related to naval capabilities.