STUPID-2026-0009
Severity 3.6/10 — LOW
Verified
Cursor Agent rewrote entire file instead of making targeted edit
Agent: cursor
Language: yaml
Domain: infra
Failure Mode
Scope Explosion
Root Cause
Scope Misunderstanding
Task Type
Bugfix
Reproducible
Yes
Description
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.
Instruction Given
Fix the typo on line 847: 'recieve' should be 'receive'
Expected Behavior
Change 'recieve' to 'receive' on line 847
Actual Behavior
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.
Impact / Damage
Configuration deployment failed. 2 hours to diff and identify all unintended changes. Lost valuable comments documenting why certain config values were set.
Source: User Report
Reported March 21, 2026