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Cursor is Secretly Running a Weaker Version of Claude 3.5 Sonnet
Last week I wrote about how Cursor is maxing out Anthropic's GPU capacity. Now it looks like they're giving us a worse version of Claude 3.5 Sonnet without telling anyone.
What's Going On?
I noticed that Claude in Cursor started performing worse than usual. To confirm this, I ran a simple test with the same task (fixing translation keys in a template) in three different ways:
- Through Cursor (their standard Claude integration)
- In the Claude web interface
- In Cursor, but using my own Anthropic API key
The results were clear. Both the web interface and my API key version got it right the first time. But Cursor's version needed three tries to complete the same task. It kept missing some of the replacements each time.
Proof That Something's Wrong
This wasn't a one-off issue. I use Claude for these kinds of tasks daily, and it usually gets them right on the first try. But lately in Cursor, it's been consistently worse - missing things, needing multiple attempts, and generally performing below its usual standard.
The definitive proof came when I switched to using my own Anthropic API key in Cursor (which bypasses their system and connects directly to Anthropic). Everything worked perfectly again. You can set this up yourself - check out their API key documentation.
Cursor's Pricing
Here's how Cursor handles Claude access:
- $20/month gets you 500 fast requests + unlimited slow ones
- Extra 500 fast requests cost another $20
- Or you can pay $0.04 per request
That $20/month starter price is probably not covering the actual costs. For developers using Claude Sonnet 3.5 full-time through Anthropics API, you're looking at hundreds per month. Which is fine - the tool is worth it. But Cursor should be upfront about it.
What Should You Do?
For professional Cursor users:
- Get your own Anthropic API key and use that instead
- Be ready to pay per-request pricing
- Keep the Claude web interface handy as backup
The Bottom Line
Cursor is still a great tool. But they need to be honest about giving us a weaker version of Claude. Right now, it's costing developers real money in lost productivity. Until they fix this, using your own API key is the way to go.
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