Frontier AI keeps racing despite calls to slow down

Despite a July open letter from AI company employees calling for frontier AI labs to slow their pace of development, a message echoed by Anthropic CEO Dario Amodei earlier this month, major model releases continue to appear at quite a clip. Anthropic and OpenAI each released new versions of their Claude and GPT models on Tuesday: Opus 5.5 and GPT-6 Sol and Luna. "We must slow the pace at which we improve the capabilities of AI models," said Amodei in an online post on September 12, 2026, reitera