Are you excited about open-source software, developer tools, and the future of agentic applications? We are looking for a Senior Software Engineer to help build the core libraries, evaluation systems, and reusable harness capabilities that make AI agents safer, faster, and easier for developers to trust. In this role, you will work hands-on across open-source agent harnesses, sandboxed execution, model-provider infrastructure, and agent benchmarks to help improve the next generation of agents. You will turn agent-evaluation evidence into real improvements: diagnosing failures, contributing upstream, and proving quality, reliability, cost, and latency gains across models. Join our creative engineering team building foundational technology for the future wave of autonomous software systems!