Software Engineer, Agent Harness
Confirmed on the employer's own hiring board on Sep 23, 2026. First seen by Alion on Aug 26, 2026.
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 Role
The 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.
Applying
If 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.