Founding Engineer — AI Agents

About the role

Cosine is building autonomous software engineering agents. As a founding engineer, you'll have outsized impact on the core agent architecture — from planning and code generation to self-healing and evaluation. We're a small, fast team backed by top-tier investors.

Responsibilities

• Build and iterate on core autonomous coding agent capabilities
• Design evaluation frameworks to measure agent reliability and code quality
• Work directly with founders to define product direction and technical strategy
• Ship fast — we deploy multiple times per day and measure everything
• Hire and mentor the next wave of engineers

Requirements

• 4+ years of software engineering experience
• Strong TypeScript / Node.js skills
• Experience working with LLMs in production (prompting, fine-tuning, or agent orchestration)
• Comfortable in ambiguity — you thrive in early-stage environments
• Demonstrated ability to ship quickly without sacrificing quality