Founding AI Engineer

Mason AI is on the frontier of agentic AI for the built world: we're the technical leaders at building AI that checks blueprints are buildable and safe.

We're looking for a Founding AI Engineer to improve Mason's accuracy on our evals. You will go deep on the cutting edge of optimizing multimodal AI agents. We have similar technical problems as other agentic AI startups, stacked on top of AI for legal reasoning, spatial reasoning, and visual understanding. Your work will directly affect the built environment of California within the first month of joining.

You will have a massive impact on the product, the company's future, and the country's, as we accelerate American construction. Join us.

• Either a SWE passionate about growing as an ML/AI Engineer, or a ML Engineer who's fast at prototyping.

• You can run experiments quickly and develop research taste.

• You're mission-oriented and looking for your life's work. You care about America's ability to build.

• You love ownership and don't mind ambiguity or unblocking yourself.

• You have the curiosity of a policy wonk to digest building codes and architectural diagrams.

• 60+% of your time will be spent improving the accuracy of our multimodal agents that check blueprints for building code compliance. This can range from building autoresearch to improving our evals to running sweeps on new experimental features you build. Your research taste will direct this work.

• Talk to users and dogfood the product weekly

• Wear hats as needed on topics ranging from running computer vision experiments, lightweight data engineering, building internal tooling, improving the webapp, and more.

• Fail fast and cheap. Slugging percentage matters more than batting average.

• We can make a lot of mistakes as long as we get a few things right.

• A written culture - we document our thinking on the few things that matter most.

• Internal tooling is a first-class use of time.

• In-person work is a must.

• Competitive salary ($160k-$210k).

• Generous early-stage equity (0.75%-2%).

• Free lunch and dinner (ordered at 6 pm) at the office.

• Fully paid health insurance with over $1000/year in employer contributions to an HSA.

• A 401(k) that accepts pre-tax and Roth contributions.

• A commuter benefits account and a monthly wellness benefit.

• Opportunity to shape the future of our country.

Our interview process aims to be lightweight and respect candidates' time. We expect it to take 2 weeks or less.

• Intro call (30 min) - Informal chat on your interests and experience

• AI Coding & Culture interviews (90 min)

  • Designed to mirror real work you'd do at Mason, you'll build a prototype for a slice of our product. AI coding tools (e.g. claude code, conductor, wisprflow) are strongly encouraged.

  • Learn more about how you've navigated challenges in (or outside) of work.

• Paid work trial (3 days) - We'll set you up to run evals for our multimodal agent on our repo, and we'll ask you to generate hypotheses for experiments to run, run those experiments, and then analyze them. You'll be evaluated on your speed at running thoughtful experiments.
  We're flexible on scheduling
  , and usually run these over the weekend to minimize impact on your weekday schedule.

• Full-time offer