Scale Engineer

Software Engineer, Agent Harness

Software Engineer · Senior · Full Time

San FranciscoUSD 150k – 250k10mo ago
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Role

What you'll do.

Cursor is seeking a talented Software Engineer for their Agent Harness team to develop core AI agent capabilities and infrastructure. The ideal candidate will help define advanced agent experiences, build extensible platforms, and make critical decisions in AI model integration and behavior optimization.

Responsibilities

  • Agent Harness Development: Advance the core agent infrastructure including agent loop, tools, prompts, and execution environment to enable easy extension by Cursor engineers
  • Agent Experience Optimization: Improve the default Cursor agent experience by making intelligent model choices based on user needs, capabilities, and cost considerations
  • Model Integration: Partner with foundational model providers and research teams to integrate, evaluate, and roll out new AI models end-to-end

Qualifications

What we look for.

Technical

  • Software Engineering

    Proven ability to build and ship robust production systems

  • AI Infrastructure

    Deep understanding of AI agent architecture and behavior

Education

  • Computer Science

    Bachelor's or equivalent degree in Computer Science, Software Engineering, or related technical field

Experience

  • Agent Development

    Demonstrable experience in building complex agentic products or infrastructure

  • Production Systems

    Track record of shipping scalable, production-ready software solutions

Skills

Required

  • Software Engineering

    Strong fundamentals in building production systems

  • AI Agent Development

    Experience with complex agentic product infrastructure

  • Systems Design

    Ability to create extensible platforms and tools

Preferred

  • AI Model Integration

    Nice to have

    Experience working with foundational models and AI technologies

  • Product Engineering

    Nice to have

    Background in building tools used by other engineers

  • Decision Making

    Nice to have

    Strong ability to make nuanced decisions in complex scenarios

Tech stack

Languages

PythonJavaScript

Frameworks

AI FrameworksBackend Frameworks

Databases

Distributed Databases

Tools

Version ControlCI/CD

Other

AI Model Platforms

Compensation

Pay and benefits.

Base·USD 150,000 – 250,000

Equity·Stock options

Benefits

  • Innovative Work Environment

    Opportunity to work at the forefront of AI productivity tools with a talented, passionate team

  • Flat Organization

    Collaborative and non-hierarchical company structure that values creative problem-solving

Process

Interview steps.

  1. 01

    Initial Screening

    Initial review of application and qualifications

  2. 02

    Technical Interviews

    2-3 short technical interviews to assess engineering skills and AI expertise

  3. 03

    Onsite Interview

    In-office interview involving a small project, team discussions, and technical evaluation

Full posting

Original listing.

Our mission is to automate coding. The first step in our journey is to build the best tool for professional programmers, using a combination of inventive research, design, and engineering. Our organization is very flat, and our team is small and talent dense. We particularly like people who are truth-seeking, passionate, and creative. We enjoy spirited debate, crazy ideas, and shipping code.

About the Role

As a Software Engineer on the Agent Harness team at Cursor, you’ll build the core agent behavior and capabilities that power agent experiences across Cursor products. This spans agent orchestration, tools, guardrails, and model behavior tuning—designed as a platform that Cursor engineers can extend and depend on.

Your work will also define the default Cursor agent experience (”Auto”), where users trust us to make the right model choices under real-world constraints.

Example projects include:

  • Advancing the agent harness (agent loop, tools, prompts, execution environment, capabilities) used across Cursor products, in a way that makes it easy for Cursor engineers to extend and use.

  • Improving the default Cursor agent experience (the “Auto” model setting): making smart model choices based on user needs, model capabilities, and cost appetite.

  • Launching new models on Cursor end-to-end — partnering with foundational model providers and our research team on integration, evaluation, and rollout.

You may be a fit if

  • You have built complex agentic products or infrastructure. You have taste and strong opinions on model and agent behaviors.

  • You have strong software engineering fundamentals and enjoy shipping production systems.

  • You make good calls in the gray area: weighing data, user experience, and product taste when there isn’t a single “right” answer.

  • Experience building products or tools used by other engineers is a plus.

Applying

If there appears to be a fit, we'll reach to schedule 2-3 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.

#LI-DNI

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