Software Engineer, Agent Harness

Sim is talent-dense. We're looking for special people who are mission-driven, passionate, and creative.

We're a team of 10 working full-time, in person in San Francisco. We have a flat organization: you'll work directly with the founders and own your work from idea to execution. We sponsor visas.

The agent harness is Sim. It's the agent that ingests and reasons over a knowledge graph of company context to build and operate agents. You'll own the systems that make this possible: context retrieval, planning and execution, tool use, memory, and recovery from failure. You'll build evals and use production traces to improve how the harness translates company knowledge into reliable agent behavior. Those findings will shape the harness architecture and the capabilities we build next.

• You can reason about how agents retrieve and use company context, including knowledge graphs, tool calls, memory, and context management, and translate that understanding into reliable systems.
• You can design evals, diagnose failures across retrieval, model behavior, and execution, and use evidence to improve task quality, latency, and cost.