What if your browser knew your entire workday — and could quietly handle the parts that drain your focus?

In this episode of First Commit, Eliya Elon and Laura Hamilton sit down with Regina Lin, co-founder and CEO of ThirdLayer, the company building Dex — an AI workspace that lives inside Chrome and acts as a true knowledge worker for the browser. 

Regina started building Dex as a college side project with her co-founder Kevin while juggling a math degree and years of competitive piano performance — originally just trying to get GPT-4o to order DoorDash at midnight. The insight that it could replace entire categories of manual, browser-bound work crystallized when they snuck into a Boston AI conference with fake lanyards and ran into someone managing hundreds of UiPath bots. What Dex became is a hybrid agent that pulls context directly from the browser while executing actions through precision tool calling — not screen scraping, not MCP — built for the knowledge workers who spend every minute of their day living in tabs.

Join us as we explore:

• ICP Discovery: How Regina landed on go-to-market professionals as the core user — people whose entire workday is implicit, scattered across tabs, with no to-do list because their to-dos are the tabs.
• Hybrid Agent Architecture: Why Dex combines browser context with custom tool calling for maximum accuracy — and why the "pure browser agent" framing misses what actually makes it fast.
• The Education Problem: Why giving people agents isn't enough — and how human creativity, not technology, turns out to be the real bottleneck to adoption.
• Lessons from Piano: How eight-hour practice days, public masterclass critiques, and improvising a concerto ending she'd forgotten trained Regina for the pressure of building in real time.

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