Founding AI Engineer

Job Description

Job Description

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 spatial reasoning and computer vision. 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.

Who you are

• An AI-pilled SWE with 3+ YoE . You know how to make mature architectural decisions for core modules, but you're AI-pilled enough to work with parallel workflows for lighter weight work.

• You're mission-oriented and care about solving the housing crisis.

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

What you'll do

• 50+% of your time will be spent improving the accuracy of our multimodal agents that check blueprints for building code compliance. Think post-training models and autoresearch.

• Wear hats as needed on topics ranging from lightweight data engineering, setting up the team's coding agents for success, building internal tooling, improving the webapp, and more.

• Boil lakes by building new agents that extend our existing offering to commercial and multifamily housing across the country

• Talk to users weekly

Our operating principles

• 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.

Benefits

• 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.

Interview process

Our interview process aims to be lightweight and respect candidates' time. We can fit it in 2 weeks.

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

• AI Coding & Technical Disagreement 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, wsprflow) are strongly encouraged.

  • Give us a play-by-play of a technical disagreement at work. We're looking for important disagreements with conflict.

• 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

Note: We are unable to offer visa support.

Compensation Range: $160K - $210K