As a Member of Technical Staff - Software Engineer on the Capabilities team, you will build the environments that expose those failures and help models improve on them. You will own our most complex tasks end-to-end: environments with multi-step workflows, realistic stakeholder interactions, large codebases, and challenging system design problems. You will work closely with a small team of engineers and directly with our founders, and you will ship environments that go into the training loops of frontier models at our partner labs. This is independent, high-ownership work with regular feedback.