# Software Engineer, Agent Harness

**Company:** [Sim](https://hotfix.jobs/companies/sim)
**Location:** San Francisco, CA
**Role:** Fullstack Engineering
**Salary:** $210k – $260k/yr
**Skills:** LLMs, Tool Calls, Context Management, Retries, Evaluations, Infrastructure, Memory Systems
**Posted:** 2026-08-26

> Build the agent harness that plans tasks, calls tools, uses memory, recovers from failures, and operates reliably at scale. The role requires strong reasoning about LLM behavior and the ability to translate it into robust infrastructure.

## Job Description

## Responsibilities
- Build the agent harness that powers workflow and table creation, knowledge bases, and everyday tasks.
- Design and implement how the agent plans, calls tools, uses memory, recovers from failure, and runs reliably at scale.
- Support infrastructure for more than 100,000 builders.

## Requirements
- Ability to reason clearly about large language model behavior, including tool calls, context, retries, and evaluations.
- Ability to turn that understanding into robust infrastructure.

## Compensation
- $210,000–$260,000 base salary.
- 0.2%–0.8% equity.

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