Software Engineer, Agent Harness

About Sim

The AI Workspace for Building and Managing AI Agents.

Tech

At Sim, our stack sits at the frontier of AI: multi-agent orchestration, MCPs, advanced LLM capabilities, browser agents, and more. We’re constantly working to translate the latest advances from AI research labs into a platform that builders can use to create powerful AI agents. This means solving challenging problems in orchestration, reliability, and scale while pushing the boundaries of what AI agents can actually do in real-world environments.

The role

Our mission is to automate knowledge work. The first step in our journey is to build the best tool for teams to build agents. Sim is talent-dense. We're looking for special people who are mission-driven, passionate, and creative. About the RoleThe agent harness is Sim. It's the agent that builds workflows, tables, creates knowledge bases, and does everyday tasks. As a member of this team, you'll build the agent that builds everything else: how it plans, calls tools, uses memory, recovers from failure, and runs reliably at scale for 100,000+ builders. You may be a fit if• You can think clearly about LLM behavior (tool calls, context, retries, evals) and you can turn that intuition into robust infrastructure. Compensation$210K–$260K base plus 0.2%–0.8% equity. ApplyingIf there appears to be a fit, we'll reach out to schedule 1-2 short technicals. After, we'll schedule an onsite in our office, where you'll work on a small project, discuss ideas, and meet the team.## **Equal Opportunity**Sim is committed to creating an inclusive environment for all employees. We celebrate diversity and are committed to creating an inclusive environment for all team members. We do not discriminate on the basis of race, religion, color, national origin, gender, sexual orientation, age, marital status, veteran status, or disability status.