Software Engineer, Agent Harness at Sim

About the role

What will you do at Sim?

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.

Which skills does this role require?

LLMs

Make your next move

Build a shortlist and prepare

Identify the requirements you can demonstrate, then choose examples from your work to discuss with the hiring team.

Build a focused shortlist before you applyCompare role requirements with your experience and give each application a clear reason.
Practice explaining your experience in an interviewRehearse your answers before meeting the hiring team.

Review the responsibilities and requirements before adding an opening to your shortlist.