River AI raises $1.1B seed round for personal AI agents

River AI, a two-month-old startup founded by xAI co-founder Babuschkin, raised a $1.1B seed round led by General Catalyst to build personal AI agents with a 'guardian angel' vision. The company offers an enterprise RL fine-tuning API at 2-4x cost savings, signaling massive investor appetite for agentic AI and adding to the AI vendor funding landscape.