Software Engineer, Agent Harness

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 [hidden], you’ll build the core agent behavior and capabilities that power agent experiences across [hidden] products. This spans agent orchestration, tools, guardrails, and model behavior tuning—designed as a platform that [hidden] engineers can extend and depend on.

Your work will also define the default [hidden] 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 [hidden] products. This would shape and empower experiences like multi-agent coordination.

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

• Shaping the default [hidden] agent’s personality.

• Launching new models on [hidden] 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 strong software engineering fundamentals and enjoy shipping production systems.

• You have taste and strong opinions on model and agent behaviors. You stay up-to-date and informed on emerging research and industry trends.

• 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 eval datasets or frameworks to understand and improve the performance of AI systems is a plus.

• 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.

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