Multiple Large Cache Write and Wrong Cost Calculation

[idham]

Where does the bug appear (feature/product)?

Cursor IDE

Describe the Bug

I have two issues:

1. Cursor repeatedly writes to cache during the same chat session within a short time, but there are zero cache reads. See the screenshot—those three events are from a single chat, resulting in a $6 cost because it writes a large amount of data to the cache but doesn’t read it for the next request within the same session.

   

2. The calculated cost based on Anthropic’s published pricing differs. It seems the calculation is incorrect, those cost $2.56 according to cursor but based on my calculation it is $2.1(assume >200K token ) (see the image).

   

Steps to Reproduce

Use chat as usual

Screenshots / Screen Recordings

Operating System

MacOS

Current Cursor Version (Menu → About Cursor → Copy)

Version: 1.7.44
VSCode Version: 1.99.3
Commit: 9d178a4■■■89981b62546448bb32920a8219a5d0
Date: 2025-10-10T15:43:37.500Z
Electron: 34.5.8
Chromium: 132.0.6834.210
Node.js: 20.19.1
V8: 13.2.152.41-electron.0
OS: Darwin arm64 25.0.0

Does this stop you from using Cursor

No - Cursor works, but with this issue

[TRTRTRTR]

Are you sure you’re not running a new chat after every prompt?

[idham]

I am sure, i have check the history. only 1 chat until now

[idham]

It seems Cursor uses a 5-minute cache expiration time. This significantly increases our costs because it writes to the cache almost every time but expire before we continue, as in many cases we continue chat after more than 5 minutes.

[condor]

hi @idham I will check this with the team. I’ve sent you a DM.

[condor]

We are currently using the 5 minutes cache expiration time. That is correct.