I’ve been trying to migrate an application of mine to GPT-5 since yesterday. Wow, it’s been like giving birth… and a complicated one. It’s the second time I’ve suffered with this. Before, it was the change from the Assistants API to Responses.
You know what breaks? The models have no knowledge of these new services, so they say you’re using the wrong model, delete everything you did and go back to the default. Both Lovable and Codex did this and broke my whole application.
What was my way out? Deep Research connected to the GitHub project, passing along all the links on how to migrate. In other words, researching the “how” is still on me, even using GPT-5. I’m doing it (present continuous, really) at this very moment for the model migration. In the past it worked for the migration to the Responses API.
Besides that, you need to stay alert, because in later updates coding agents delete everything they did because they don’t “know” the new implementations.
Good luck to anyone migrating. \o/
Originally written in Portuguese and published on LinkedIn on August 8, 2025. I translated it into English with the help of AI (Claude): it let me bring my LinkedIn posts to people who don’t read Portuguese without rewriting each one from scratch. I reviewed the translation to keep my original meaning and tone.