Claude Code running on Bun is an obvious justification, but Buns features (high performance runtime, fast starts, native TS) are also important for training and inference. For instance, in inference you develop a logical model in code that maps to a reasoning sequence, and then execute the code to validate and refine the model, then use this to inform further reasoning. Bun, which is highly integrated and highly focused on performance, is an ideal fit for this. Having Bun in house means that you can use the feedback from all of automation driven execution of Bun to drive improvements to its core.