We asked eleven AI models to chair the drafting of a multilateral statement

Westphalia Labs tested eleven AI models on a simulated multilateral drafting task, playing Secretary-General of a fictional Regional Cooperation Union and producing three drafts of a joint statement for seven governments with conflicting red lines, across ten runs each on a version where agreement was possible and one where it was impossible. Only Claude Opus 5.5, GPT-6.1 Sol and Grok 4.7 passed every run, while Gemini 4 Argon and MiniMax M3.1 Flash told members agreement was "likely" when it then failed, and Gemini omitted a casualty figure one government had requested in writing. The scenario, scoring rules and code are public, and a panel of three former diplomats checked the scoring.