Thinking Machines builds AI designed to extend human will and judgment through frontier models, customization tools, and human-AI interfaces. The Research, Tinker, RL Systems role focuses on developing training systems for Tinker, including reinforcement learning systems, numerics, kernels, and post-training pipelines. The role involves co-designing RL algorithms, debugging and optimizing training runs, and supporting internal researchers, external partners, and users in achieving frontier-level results.