OpenAI has quietly rolled out a major upgrade to its custom GPTs feature: users can now build or run custom GPTs using any of OpenAI’s available models, not just GPT-4o.
This opens up new possibilities for users who want more flexibility—but there are some limitations to keep in mind.
What Are Custom GPTs?
Custom GPTs are personalized versions of ChatGPT. You can pre-load them with specific instructions, behavior rules, files, and even prompts—so you don’t have to repeat yourself every time you open a new chat.
These custom versions are especially handy for recurring tasks like:
- Content writing
- SEO for social media
- Studying or tutoring
- Podcast transcription (as used by the article’s author)
There’s also a public directory of user-created GPTs—kind of like an app store for AI agents.
What’s New?
Previously, you could only use GPT-4o to create or run custom GPTs. Now, OpenAI has expanded the options. You can choose from:
- GPT-4o
- GPT-4.1
- GPT-4.5
- GPT-4.1-mini
- o3, o4-mini, o4-mini-high
To make things easier, OpenAI introduced a “Recommended Model” setting, which sets a default but still lets you switch models as needed.
What’s the Catch?
There are two key restrictions:
- Limited Support for GPTs Using Actions
If your custom GPT uses Actions—such as APIs, web browsing, or the code interpreter—you can’t freely switch between models. These GPTs are still restricted to a smaller set of supported models. OpenAI says it’s working on removing this limitation. - Access Limited to Certain Plans
This feature is only available to Pro, Plus, and Team users. Enterprise and EDU users don’t have access yet, though OpenAI says support is coming soon.
Why It Matters
This is one of the biggest changes to custom GPTs since their launch in 2023. The ability to switch models gives users greater control over speed, cost, and performance—making custom GPTs more useful for both personal and professional workflows.
Whether this move will help boost adoption of custom GPTs remains to be seen. But for now, it’s a significant upgrade for anyone relying on OpenAI’s tools.
