xAI launched Grok 4.1, achieving a #1 rank on the LM Arena Text Leaderboard with an Elo score of 1483, showing improvements in creative writing and anti-hallucination. OpenAI's GPT-5.1 "Thinking" demonstrates efficiency gains with ~60% less "thinking" on easy queries and strong ARC-AGI performance. Google DeepMind released WeatherNext 2, an ensemble generative model that is 8× faster and more accurate for global weather forecasts, integrated into multiple Google products.

Sakana AI raised ¥20B ($135M) in Series B funding at a $2.63B valuation to focus on efficient AI for resource-constrained enterprise applications in Japan. New evaluations highlight tradeoffs between hallucination and knowledge accuracy across models including Claude 4.1 Opus and Anthropic models.