Plan mode failing repeatedly to update the plan

Bug Reports
1

Where does the bug appear (feature/product)?

Cursor IDE

Describe the Bug

Being in plan mode, when I ask to update the plan, more often than not, the update will fail. It seems related to a problem with content changing somehow so it can’t match string to update.

When asking the AI agent why it failed. I get:

It looks like updating the plan failed, could you explain why this happened, provide a brief answer then wait.

The update failed because the old_str didn’t exactly match the plan content. The tool requires an exact match, including whitespace and formatting.
Possible causes:
The plan content differs slightly from what I used
Whitespace/formatting differences
The section text isn’t exactly as stored
I can:
Read the current plan to get the exact text, then update it
Or create a new plan with the corrected mock data approach
Which do you prefer?

Steps to Reproduce

Switch to plan mode. I’m using “auto” as agent. Ask to create a plan for something. It will work. Then ask to update. It might work but for me it’s failing often.

Expected Behavior

Updating the plan should not fail.

Screenshots / Screen Recordings

planmodefail.png
planmodefail.png978×1204 96.6 KB

Operating System

MacOS

Current Cursor Version (Menu → About Cursor → Copy)

Version: 2.1.46 (Universal)
VSCode Version: 1.105.1
Commit: ab326d0767c02fb9847b342c43ea58275c4b1680
Date: 2025-12-02T03:59:29.283Z
Electron: 37.7.0
Chromium: 138.0.7204.251
Node.js: 22.20.0
V8: 13.8.258.32-electron.0
OS: Darwin arm64 24.5.0

For AI issues: which model did you use?

Auto

For AI issues: add Request ID with privacy disabled

d11df5f3-12e1-4989-b4e5-6cd988b7e422

Does this stop you from using Cursor

Sometimes - I can sometimes use Cursor

2

Hey, thanks for the report. This is a known issue. Plan Mode: the plan update tool requires an exact text match (including spaces/formatting), which often causes updates to fail.

Confirmed case and temporary solutions here:

While we fix it, try:

  • Copy the plan’s markdown into a new agent window and continue from there
  • Or save the plan to the working folder .cursor/plans and edit/recreate the plan from there
  • If you want to try updates: first ask the agent to “read the current plan” and use the exact text for replacement

Could you please share:

  • Screenshots of errors from Help → Toggle Developer Tools → Console at the time of the crash
  • Results of running with extensions disabled: cursor --disable-extensions
  • Whether it reproduces in a new chat with a fresh plan

Let me know if any of these options help. I’ll attach your case to the investigation.