Circle offers a remote, full-time Lead Engineer position for their AI Platform team. The role involves building evaluation infrastructure, diagnostic tooling, and managing the AI Quality engineering team. What you will do • Build and own our evaluation infrastructure. • Diagnose exactly where quality breaks down. • Grow the datasets that make evaluation possible. • Run structured experiments across prompts, models, and the agent harness. • Lead and grow the AI Quality engineering team. • Partner closely with AI Core engineering. What they ask for • 7+ years of experience building and shipping production software. • Experience with LLM-powered agents that take real actions in a product. • Comfortable in Ruby on Rails / Python or ready to pick them up quickly.