Where does the bug appear (feature/product)?
Cursor IDE
Describe the Bug
The provided tooling for editing files can’t handle multiple edits close to one another.
‘Failure’ cases involve the model trampling over its own edits.
‘Critical failure’ cases involve the model trampling over its own edits then declaring the file is in a state it isn’t.
The model should be able to consistently make fine-grained edits. The ‘context’ of edits should be robust to the model’s own edits (and ideally, the edits of a human interactively correcting those edits).
The models will often make multiple edits across a single file, so this happens all the time in real world codebases outside of these reproductions. This results in a massive amplification of tokens required, often causing the model to re-read entire files. The time cost is also greatly amplified, often resulting in multi-minute waits during which the editing experience is terrible, since the model is thrashing the file.
Of course since the context itself grows linearly, the resulting token bill increases quadratically. I upgraded to a Pro+ subscription just to do these tests!
To quote the model itself:
This is maddening. The application continues to undo my edits.
It’s difficult to debug this on the user end since the provided edits in the file card are nonsense, see File edit card is pretty broken
I’ve had this issue happen with every model I’ve tried in real projects. This editing problem is ultimately a fundamental issue with the file editing system design, rather than with any particular model.
Steps to Reproduce
I made sure to disable privacy mode for all these tests, I’ve been doing them over the past few days, and there have been several updates in that time but I’m still getting failures. It is also frustrating to not have any visibility of what changes version-to-version. When a version is released, the changelog should be public, not days or weeks later.
Reproduction 1
Any request to edit two lines close to each other with multiple tool calls causes this problem, I’ve been trying various prompts, this is one:
In two calls to edit_file, update the keys array to include capital letters, update the records = [] line to be a string array.
Here are a bunch of request IDs with their models and how they failed.
I’ve noted how many tool calls in brackets, and success, fail / critical fail as per above criteria.
gpt-5
2e5daefc-686a-4617-bf54-bfad7aa04b6d - fail (3)
0c24bcba-98c6-4a74-9f38-46f149312f2a - fail (9) over 5 minutes of real-time, 260.8K total tokens for a 2 line edit.
edd050f1-d99e-4edb-b045-b01bc7374eb8 - fail (12)
bd160abc-e3b4-44ba-83e7-611c99ecae2e - fail (12) many minutes, hundreds of thousands of tokens.
gemini-2.5-pro
27dfa513-a208-4fc0-9371-e9abdb8e7fe2 - critical fail (2)
cf0cc3ef-6b44-4ff1-bf9c-a22746d93bcd - fail (3)
530b658c-6670-4658-a204-27d8c9389f57 - success!
gemini-2.5-flash
3c80e9dc-afe1-4196-8c14-92c4fd47a010 - fail (5)
531665d2-5646-414d-82a6-4c2a187d9d4f - success!
595d8b1c-e9d9-4e62-9c5b-4d1f7bb6d35a - fail (4)
claude-3.5-haiku
7bf871c7-e872-4fbd-8f60-5ed598170a23 - critical fail (2)
16578b41-f30b-4e6b-b334-c347acf8a5d9 - critical fail (2)
cb5f7c09-a140-4f4e-b534-a5d683aa6c93 - critical fail (2)
06cb0903-48b4-41a7-ba63-1bee8b3f4884 - critical fail (2)
claude-4.5-sonnet explicitly reads the files in-between edits to keep consistent state.
b5e36bfe-6059-4832-ac46-18fd7c052604 - success
677b09b8-efc6-412f-9e81-a081aaaa9da9 - success
304db461-603a-4ba0-ae70-fdef7e8685c9 - success
claude-4.1-opus consistently succeeds without explicit reads in between by internally keeping track of the changes.
700fbf95-b52d-4c30-9a6d-c50bb7227375 - success
54e6047d-d4b1-43d4-b8e2-cdb2025e72e1 - success
5ee78087-1381-475c-bb0f-baf0b8b37865 - success
Reproduction 2
File
// minimal-test.ts
const a = "b";
const b = "b";
const c = "c";
Prompt
In two tool calls to edit_file, update 'a' to 'A', and update 'c' to 'C' in 'minimal-test.ts'.
claude-4.5-sonnet
b4a2a6c8-e3fd-4a3e-b046-5784f124226f - critical fail (2)
ad8131f3-0d13-4413-97b4-bc60fdbef138 - critical fail (4)
claude-4.1-opus
ad8131f3-0d13-4413-97b4-bc60fdbef138 - fail (3)
0067efe1-a2f8-41c1-a42c-3707e45a2712 - fail (5), used search_replace at the end
Expected Behavior
File editing should be robust.
Operating System
MacOS
Current Cursor Version (Menu → About Cursor → Copy)
Version: 1.7.39
VSCode Version: 1.99.3
Commit: a9c77ceae65b77ff772d6adfe05f24d8ebcb2790
Date: 2025-10-08T00:33:20.352Z
Electron: 34.5.8
Chromium: 132.0.6834.210
Node.js: 20.19.1
V8: 13.2.152.41-electron.0
OS: Darwin arm64 24.6.0
For AI issues: which model did you use?
I’ve attached request IDs for the following models, this happens across all models I’ve tried.
gpt-5
gemini-2.5-pro
gemini-2.5-flash
claude-3.5-haiku
claude-4.5-sonnet
claude-4.1-opus
Does this stop you from using Cursor
Yes - Cursor is unusable
