Anthropic is seeking a Research Engineer for their Reinforcement Learning Fundamentals team. This role involves collaborating with researchers and engineers to advance large language models through reinforcement learning research. Key responsibilities include developing novel RL techniques, creating tools for complex tasks, and enhancing reasoning capabilities in areas like code generation and mathematics. The ideal candidate has 5+ years of industry experience, proficiency in Python and deep learning frameworks, strong software engineering skills, and a passion for AI safety. The role offers competitive compensation, including a salary range of £250,000 - £340,000 GBP, equity, and comprehensive benefits. Anthropic values diversity and encourages applications from all backgrounds. The company operates on a hybrid work model, with at least 25% office presence required, and offers visa sponsorship. Anthropic is committed to big science AI research, working as a cohesive team on large-scale efforts to create steerable, trustworthy AI systems.