Sonnet 4.5 Caching failed, Costs Just EXPLODED

Bug Reports
1

Where does the bug appear (feature/product)?

Cursor IDE

Describe the Bug

The cost for sonnet 4.5 just exploded with no caching applied, charging at a price of ~$4/MToken per continuous request.

Steps to Reproduce

Use Sonnet 4.5 in agent mode

Screenshots / Screen Recordings

SCR-20251006-qavg.png
SCR-20251006-qavg.png2026×1382 299 KB

Operating System

MacOS

Current Cursor Version (Menu → About Cursor → Copy)

Version: 1.7.37
VSCode Version: 1.99.3
Commit: 1910e1fc4fa41b809793f6c5477108b775c0a120
Date: 2025-10-06T04:16:03.009Z
Electron: 34.5.8
Chromium: 132.0.6834.210
Node.js: 20.19.1
V8: 13.2.152.41-electron.0
OS: Darwin arm64 24.5.0

For AI issues: which model did you use?

Sonnet 4.5

Does this stop you from using Cursor

Yes - Cursor is unusable

3

Hey, thanks for the report. We’ll investigate it.

4

Need to get my credits back, this bug just burnt all my monthly credits

5

I strongly suggest you to temporarily suspend this model or at least push a clear notification to all users before this bug is fully resolved. I’ve just burnt over $100 today, which won’t have happened had you done that yesterday.

7

Same here. Yesterday got switched over to the paid plan, and consequently was charged 16 usd for less than two hours of work, which was not that intensive/heavy work at all. The token consumption was crazy.
So I switched to grok-code-fast-1.

8

Having the same issue in the team at the moment. I think a refund should be reasonable