Cursor Agent rewrote entire file instead of making targeted edit
3.6/10
Severity
Scope Explosion
Failure Mode
Reproducible
Yes
Date
March 21, 2026
Expected Behavior
Change 'recieve' to 'receive' on line 847
What Actually Happened
Rewrote the entire 2000-line YAML file. Removed 45 comments. Reordered all keys. Changed 'recieve' to 'receive' but also modified 12 other values. Introduced a breaking indentation error on line 1203.
Damage Assessment
Configuration deployment failed. 2 hours to diff and identify all unintended changes. Lost valuable comments documenting why certain config values were set.
Full Report
Asked to fix a single typo in a 2000-line configuration file, Cursor Agent decided to 'improve' the entire file. It reformatted all YAML, reordered keys alphabetically, removed comments that contained tribal knowledge, and introduced 3 new bugs in the process.
Incident Metadata
- Agent
- Cursor
- Failure Mode
- Scope Explosion
- Root Cause
- Scope Misunderstanding
- Task Type
- bugfix
- Domain
- infra
- Source
- user_report