Member of Technical Staff

Cortex Ventures; New York (NY); On-site; USD 140,000 - 210,000; Full time

Job summary

Cortex, an AI-native holding company for engineering services in New York, seeks a Member of Technical Staff to build AI systems at its center: agents that perform real engineering work and the software that makes them usable by engineers.

You’ll work end-to-end—from deciding where an agent helps, to building, evaluating, and shipping across the front end, back end, data and deployment.

Qualifications

• Built products from zero to one in startups or small teams.
• Experience with large language models beyond a demo.
• Full-stack engineer capable of frontend, backend, and deployment.

Responsibilities

• Build agents that do real engineering work (planning, tool use, retrieval, hand-offs).
• Create evaluations and regression suites to measure agent quality.
• Ship full-stack products across UI, backend, data, and deployment.
• Work directly with engineers to identify bottlenecks and improve workflows.

Job description

Cortex is building an AI-native holding company in engineering services. We partner with founders of established engineering firms and develop AI tools alongside their teams to help them deliver projects faster, expand capacity, and grow.

Our approach brings together acquiring good businesses and developing technology that makes them more valuable. We’re building for long-term ownership, with an ambition to change how engineering work gets done.

The opportunity

We’re looking for a Member of Technical Staff to build the AI systems at the center of Cortex: agents that take on real engineering work, and the software that puts them in the hands of the people who use them.

The work runs end to end. You’ll sit with engineers to understand how a project actually gets done, decide where an agent can help, build it, and prove it works with evaluations before anyone relies on it. Then you’ll ship the product around it: the interface, the back end, and the connections to the tools a firm already uses.

Much of what you build won’t exist when you start. You’ll take problems from a blank page to something people depend on, and your decisions will shape our technical foundation.

What you’ll work on

• Build agents that do real engineering work. Design and orchestrate multi-step agent systems (planning, tool use, retrieval, and hand-offs between models) that take on tasks engineers do by hand today.
• Make quality measurable. Build the evaluations that tell us whether an agent is right: test sets drawn from real project work, graders, and regression suites that run on every change. Use them to decide what ships.
• Ship full-stack products. Take features from prototype to production across the front end, back end, data, and deployment, so what you build fits how engineering teams already work.
• Work directly with the people using your work. Spend time with the engineers who will use what you build, see where the work slows down, and turn what you learn into the next thing to build.

Who you are

You’ve built products from zero to one, at a startup, as a founder, or on a small team inside a larger company. You’re comfortable owning a problem when the path isn’t clear.

You’ve built with large language models beyond a demo. You’ve orchestrated agents across multiple steps and tools, and you’ve written evaluations that measure whether they work, not just whether they run. You don’t trust results you can’t measure.

You’re a full-stack engineer who moves across the front end, back end, and infrastructure without waiting on anyone. You explain trade-offs plainly and enjoy learning a field you didn’t start in. Experience in engineering, construction, or other technical services is a plus, not a requirement.

Why Cortex

Most AI products are built far from the people who use them. As engineering firms join Cortex, you’ll build alongside the engineers doing the work, see how your systems hold up on real projects, and hear directly from the people who rely on them.

You’ll join a small founding team with real ownership over what we build and how we build it.