Where does the bug appear (feature/product)?
Cursor IDE
Describe the Bug
When the agent reads files located outside the workspace root directory (in sibling/external repos), those files are silently truncated to 0 bytes. No error is shown. The agent never intentionally writes to these files — only reads them for context.
Steps to Reproduce
Open workspace rooted at directory A (e.g., an Angular project)
Have the agent use the Read tool on files in directory B (a sibling repo — e.g., a Rails API repo)
After the session completes, check the files in directory B
Files that were read are now 0 bytes
Operating System
MacOS
Version Information
Version: 3.5.33
VSCode Version: 1.105.1
Commit: aac81804b986d739acab348ed96b8bea6e83cc50
Date: 2026-05-22T06:47:48.039Z
Layout: editor
Build Type: Stable
Release Track: Default
Electron: 39.8.1
Chromium: 142.0.7444.265
Node.js: 22.22.1
V8: 14.2.231.22-electron.0
OS: Darwin arm64 25.4.0
For AI issues: which model did you use?
opus 4.6 and opus 4.7
Additional Information
Summary
When the Cursor agent uses the Read tool to access files in repositories outside the active workspace root, those files are silently truncated to 0 bytes. The files are not intentionally written to — only read for context — yet their contents are destroyed.
Environment
Cursor version: Recent (bug appeared ~week of May 19, 2026)
OS: macOS (darwin 25.4.0)
Workspace root: /Users/gary/GKB/RubyApps/TC_Rest/Hammer (Angular project)
Affected external repos:
/Users/gary/GKB/RubyApps/TC_Rest/thor (Ruby on Rails)
/Users/gary/GKB/RubyApps/angular-libraries (TypeScript/Angular)
Behavior
Agent is working in the Hammer workspace
Agent uses the Read tool (or Grep/Glob followed by Read) to inspect files in sibling repositories (Thor, angular-libraries) for context
After the session, the read files are 0 bytes on disk — contents completely gone
No error or warning is shown to the user or agent during the session
The corruption is only discovered later when the application fails to compile or run
Affected Files (Two Incidents)
Incident 1 — angular-libraries repo:
projects/thor-api/src/lib/thor-api.module.ts (zeroed from ~2KB to 0)
Incident 2 — Thor repo (5 files):
app/jobs/ub_post_charges.rb (1,985 bytes to 0)
app/modules/chargeTypes/chargeTypes.rb (10,094 bytes to 0)
app/modules/ubRateSchedules/ubRateSchedules.rb (5,481 bytes to 0)
app/services/ub_billing/charge_calculator.rb (22,604 bytes to 0)
app/services/ub_billing/reading_adjuster.rb (16,235 bytes to 0)
Key Observations
File type is irrelevant — affects both .rb and .ts files
The files were only read, never intentionally written or edited
The agent’s Write/StrReplace tools were not called on these files
The workspace sandbox is configured with “write access limited to the workspace directory” — yet files outside the workspace are being truncated
This behavior is new — the same multi-repo workflow worked without corruption prior to ~May 19, 2026
Recovery is possible via git restore since contents are committed
Does this stop you from using Cursor
No - Cursor works, but with this issue
revising - silent changes that impact my applications functionality are significant hits to the confidence we have in the code. This definitely impacts how we use cursor and if we can afford to use cursor with the additional testing requirement this adds to our job.