Model Behavior

Who you are

• 4+ years of experience in product, design, or adjacent builder roles. You have hands-on experience taking a product from concept to its initial release (v1). Previous experience as a founder is a plus
• You think in systems. You can take an ambiguous problem, break it into something measurable, and design the evals to steer it. You can navigate when to decide on a short improvement fix versus investing in systematic fixes
• You work inside AI tools daily. Codex, Claude Code, or Cursor are core parts of your workflow, and you can articulate the reasoning behind your tooling choices. You try new models and harnesses as they ship, and fold what works into how you build
• You want to be an IC. This is a hands-on role where you'll be in the prompts, code, and data yourself. You will put up multiple PRs weekly
• You're here to make an impact. Model Behavior is a small, high-output team working at the core of all our AI features. We move fast and take on hard problems, which means you'll be learning constantly and growing quickly

What the job involves

• At the Browser Company, you will play a crucial role in shaping how Dia interacts with users
• This is a hands-on role at the intersection of product and AI engineering: you will define Dia’s intended behavior, ship prompt and code changes that deliver it, and own evals that measure quality and cost. The work spans the full stack of modern AI product development: prompting, tools, model selection, agent harnesses, and evaluation systems
• You'll report to our Model Behavior Lead and work closely with engineering and product. You'll have high impact and own problems end to end: understanding what users need, deciding the right approach, shipping the change, and proving it worked
• Shape Dia's AI experience. Figure out what the right behavior is for users, then find the best path to it — a prompt change, a new tool, a different model or harness, better evals, or a spec that aligns the team
• Ship every week. This is a hands-on role: you'll be in the prompts, the code, and the data yourself, making changes that reach users continuously
• Improve systematically. Ground your work in evals that make quality trackable, so improvements hold up over time and the team can raise the bar faster with every iteration
• Build the tools that make us faster. Spot where the team's workflow is slow or manual and partner with engineering (or build it yourself) to create the internal tooling that lets us iterate at scale
• Keep us at the frontier. AI moves fast, and Dia has to move with it. You'll test new models as they ship, evaluate new harnesses, and prototype AI architecture strategies and push the ones that matter into how we build
• Morning Brief. Prototyped our best performing feature of all time. The Morning Brief started as an idea from our Head of Engineering and was handed to Model Behavior to shape and bring to life. It required forming an opinion around what a morning brief should include, how to present it, and finally how to ensure quality was acceptable
• Chat architecture. Our move to an agent harness began as a prototype over our winter shutdown. It now powers Dia's chat, and it's the latest in a line of upgrades the team has led since GPT-3.5

The application process

• Deadline to Apply: November 29, 2026 at 8:00 AM UTC

Benefits

• Choose-Your-Own-Compensation Plan: When we give you a job offer, we’ll actually give you two different offers — one that is focused on having a higher salary and one focused on higher equity. Candidates can choose either offer (or any numbers in-between) when they accept.
• Best in the Biz Insurance: We provide employees with full coverage medical, vision, and dental insurance and a free One Medical membership to help you keep you and your family healthy. We cover 100% of employee plan costs and up to 90% for dependents.
• Napping During the Workday: Some of us are better in the mornings, others are more productive in the afternoon. People should take breaks when they need to. If you’re on our team, we trust you to get your work done — our policy is: work when it makes sense for you!
• Take Time Off, Please!: We believe that people do their best work when they’ve rested and had valuable time off. So rather than having a maximum number of days off, we actually have a recommended minimum vacation of 20 days a year. Take time off when you need it and also just when you feel like it.
• Extremely Flexible Parental Leave: We are proud to offer an extremely flexible 12 weeks of parental leave — for any parent regardless of gender and for birth, adoption, surrogacy, or fostering. Take the 12 weeks all at once, or split up days to slowly transition back to work — we’re accommodating to everyone’s different situations! Birth mothers also qualify for an additional 6 weeks of medical leave.
• Design Your Dream Home Office: We are a remote first company. About half of our team currently lives outside of New York and across 5 different time zones. So if you need some stuff to make working from home a bit easier, we offer a $1000 stipend for anything you need to get comfortable.
• Cozy Office in Brooklyn, Wooo!: If you do happen to live in the New York area (or you want an excuse to visit) you can come into our beautiful office in Williamsburg. Coming into office is entirely optional, some of us come almost every day and some of us come in once a week. No obligation, we just genuinely like each other!