As a Founding Engineer at Primitive Labs, you will own the end-to-end design and delivery of agent architectures, infrastructure, and developer tooling. You’ll collaborate directly with founders and design partners to build systems that model human behavior using computational cognitive science, ensuring AI-native software is built for real-world user responses.
Founding Engineer at Primitive Labs
Join Primitive Labs as a Founding Engineer and build the behavioral intelligence layer for AI-native software. Founded by former Amazon AGI and AWS leaders and backed by a16z Speedrun and Y Combinator, we're creating agents that model complex human behavior to help product teams test features realistically. You’ll own the full stack—from infrastructure and agent architectures to computational cognitive science—working alongside a lean, elite team of builders. This is a rare opportunity to define the technical direction of a high-growth startup supported by strategic angels from OpenAI and Google. If you’re an agent-native developer ready to shape the future of software development, we want to hear from you.
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Location
San Francisco, United States
Compensation
Not Disclosed
Company
Primitive Labs
Role overview
Primitive Labs is a Y Combinator and a16z Speedrun-backed startup building behavioral intelligence for AI-native software. Founded by former Amazon AGI and AWS engineers, the team creates agents that model human behavior—thinking, buying, and consuming—allowing product teams to test features against realistic user simulations before shipping to production.
What you will do
- Architect and ship full-stack products, spanning from core infrastructure and agent frameworks to user-facing product features and evaluation systems.
- Research and implement novel agent architectures that draw on computational cognitive science to reliably model complex human behaviors.
- Partner with early customers and design partners to iterate on feedback, shaping the product roadmap and technical direction from scratch.
Who this is a fit for
- Proven track record of shipping complex, full-stack products to production with high autonomy and an owner-operator mindset.
- Agent-native developer with deep experience both using and designing AI tools and integrating them effectively into the SDLC.
- Strong interest or background in computational cognitive science, infrastructure, and building scalable systems for real-world behavioral modeling.
Why this role is remarkable
- Join an elite founding team of former Amazon AGI and AWS engineers who previously launched foundational models and major ML infrastructure.
- Backed by top-tier investors including a16z Speedrun, Y Combinator, and strategic angels from OpenAI, Google, and Amazon.
- Work at the frontier of AI, moving beyond generic models to create high-fidelity simulations of human behavior and cognitive processes.
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