Generative AI can be a powerful force multiplier for developers, but it also comes with limitations. Developers are expected to co-create with AI, and check the generated output, or risk hallucinations running wild. This can aid development at a local machine, but what happens when you try to apply these tools on a massive scale?

At Moderne we've explored Generative AI for our users, as stewards for OpenRewrite and the Moderne Platform, to automate code changes as scale. In this talk we'll take you through our lessons learned as we tried our hand at AI, to tell you what worked, and what failed, such that you can learn from our experiences. It will be an honest look back, and brief look ahead on our process, to show you how our customers can now reliably leverage AI for code modernization.