Biography
Marcus Castro is Founder and CEO of Sovrano AI, a Barcelona-based startup building Europe's human evaluation data layer for AI systems, spanning robotics, reinforcement learning and adjacent domains. He previously founded and led CareerOS, a career-placement platform that built one of the largest student networks in Europe across more than 400 universities.
Castro brings a builder's perspective on connecting verified human expertise to AI development at scale, drawing on a network of over 500,000 professionals working across more than 20 languages. His work sits at the intersection of talent, education and applied AI, focused on how structured human judgment can ground and improve AI systems rather than be replaced by them.
His perspective is especially relevant for audiences interested in AI evaluation and data infrastructure, the future of graduate careers in an AI-shaped economy, and how European startups build differentiated AI infrastructure.
Session
- AI For TomorrowSpeaker
Workshop 20 - How to write a rubric properly
Wednesday 23 September, 16:30 – 17:50Workshop Room BIn this workshop, you will learn how to evaluate frontier AI Models. You will create a checklist and have others score a model according to yours. You will learn the properties that separate a real rubric from a plausible ones, and how to balance between difficulty and plausibility.