Why My O4-mini Model Wasn’t Working in Cursor and How I Fixed It in Minutes

I was really excited to hear about the new O3 and O4-mini models in Cursor—they seemed perfect for my AI coding work. But that excitement vanished when I kept getting blocked by errors like ‘The model o4-mini does not work with your current plan or api key.’ After some frustrating trial and error, I finally got them working. Let me walk you through exactly how I fixed it.

The Core Problem I Faced

As someone who uses Cursor daily, I immediately went to Settings > Models to try O4-mini (currently free) and O3 (costs $0.30 per request).

At first, they weren’t even visible. I added them manually by clicking ‘Add model’ and typing the names. But within minutes, O4-mini stopped working completely. That error message kept popping up, and then the model disappeared entirely after a quick test chat. It felt like some backend hiccup during rollout, leaving me stuck.

The Simple Fix That Saved Me

After some digging, here’s what actually worked:

• Check for updates first: Temporary issues like this often happen during backend updates. I waited about an hour—the team confirmed they were pushing fixes.
• Re-add the models: Once things stabilized, I went back to Settings > Models, clicked ‘Add model’, and typed ‘o4-mini’ or ‘o3’ again. This time they appeared correctly.
• Verify billing for O3: Since O3 isn’t free, I double-checked my account had usage billing enabled to avoid payment glitches.

After that? Smooth sailing—no more errors or disappearing models.

Key Insights I Discovered

While solving this, I picked up some useful tips:

• O4-mini = O4-mini-high: They’re identical—no need to add both.
• O3 works text-only: Skip image inputs; it’s best for code generation.
• Pricing tip: O4-mini’s free tier is fantastic. If you’re paying $200/month for O1 Pro? Reconsider—these new options might save you money.

Oh, and O4-mini not showing its thought process? That’s intentional—not a bug!

My Top Advice for Smooth Sailing

From my experience, here’s how to avoid headaches:

• Add models manually: If they’re missing, typing them in works faster than waiting.
• Brief patience pays off: Rollout glitches usually fix quickly—grab coffee and check back.
• Use free tiers wisely: O4-mini’s free access cuts costs significantly while it lasts.

Now I’m back experimenting without issues. Try these steps—you’ll likely solve it faster than I did!