AI Engineer World's Fair 2026 — unofficial import demo

Teams shipping successful agents at scale know that model ownership is now a much more durable advantage than model choice. They’re fine-tuning open models using their proprietary data, building tight data feedback loops between their products and their models, and treating customization as a core product discipline to differentiate. I’ve spent the last decade building AI infrastructure, first as co-creator and head of PyTorch at Meta, now as CEO of Fireworks AI, where my team powers AI agent infrastructure stacks for companies like Cursor, Notion, Uber, DoorDash, and Vercel. I’ve watched hundreds of teams try to ship agents into production, and the patterns behind their success and failure are remarkably consistent. In this talk, I’ll share hard-won lessons from real production deployments across coding, productivity, and enterprise use cases, like: - Model choice matters, but model ownership matters more. Fine-tuning on proprietary data and building a feedback loop between your product and your models creates compounding advantages that no API swap will ever replicate, and it’s now the standard for all state-of-the-art models. It’s how Cursor hit 1,000 tokens/sec with quality that off-the-shelf models could never match, and it’s how Quora saw 3x speed improvements in its chatbot Poe. - The eval gap is where most agent projects die. Teams will spend months on prompt engineering and model selection, then ship without rigorous evaluation. Treating AI development with the same discipline as software development, with CI/CD, regression testing, and continuous evaluation, is what separates production-grade agents from impressive demos. A custom evaluation suite, coupled with RFT, is how Genspark achieved 12% higher quality on their trained model, resulting in a 50% cost reduction. - The real moat is the data flywheel. When you own the loop between your product, your data, and your models, every interaction makes the system better. Surrendering that loop to a third-party provider means surrendering the very data that makes your product defensible. Ownership is how Vercel created a custom code model that matched competitor quality at 40x speed. I’ll ground this talk in real examples I’ve seen work and fail across hundreds of agent deployments.