Software Engineer, Agent Harness

Cursor
San Francisco
Workplace: OnsiteFull timeFunction: Software EngineeringSkills: ["Problem-solving","Communication","Collaboration","Creativity","Critical thinking"]

Join Cursor as a Software Engineer on the Agent Harness team to build the core agent behavior and capabilities powering agent experiences across Cursor products. You’ll work on agent orchestration, tools, guardrails, and model tuning, shaping the platform engineers rely on and defining the default Auto agent experience with smart model selection under real-world constraints.

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FursaFursa
Cursor
Cursor
10 months ago

Software Engineer, Agent Harness

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Source: Company careers pageValidated by: Fursa AI
Last checked: 6 hours agoStatus: Live

Job Summary

Join Cursor as a Software Engineer on the Agent Harness team to build the core agent behavior and capabilities powering agent experiences across Cursor products. You’ll work on agent orchestration, tools, guardrails, and model tuning, shaping the platform engineers rely on and defining the default Auto agent experience with smart model selection under real-world constraints.
Location: San Francisco
Workplace: Onsite
Employment Type: Full time
Job Function: Software Engineering

Key Responsibilities

  • •Build the core agent behavior and capabilities that power agent experiences across Cursor products, including agent orchestration, tools, guardrails, and model behavior tuning.
  • •Define the default Cursor agent experience (the Auto model setting) with smart model choices based on user needs, model capabilities, and cost appetite.
  • •Advance the agent harness (agent loop, tools, prompts, execution environment, capabilities) to be easily extended and used by Cursor engineers.
  • •Launch new models end-to-end—partner with foundational model providers and the research team on integration, evaluation, and rollout.
  • •Collaborate with engineers across Cursor to ship production systems and contribute to product-driven decisions.

Key Requirements

  • •Built complex agentic products or infrastructure and have strong opinions on model and agent behaviors.
  • •Strong software engineering fundamentals and experience shipping production systems.
  • •Ability to weigh data, user experience, and product tradeoffs when there isn’t a single right answer.
  • •Experience building products or tools used by other engineers is a plus.
  • •Relevant experience with agent harnesses or similar tooling is desirable.
Skills:Problem-solvingCommunicationCollaborationCreativityCritical thinking
Languages:English

Company Brief

Cursor
Builds Cursor, an AI-powered development platform and code editor that helps developers write, review, and maintain code using large language models and developer-focused automation tools for enterprise engineering teams.
Industry: Developer Tools
Company Size: Large (251 to 1,000 employees)
Revenue: USD 1B+
Growth: Scaleup
Valuation: Unicorn (USD 1B+)
Funding: Series D
Headquarters: San Francisco, United States
Founded: 2022
Glassdoor
Glassdoor: 3.0
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