Devin built 13,600-line app with build failure instead of lean campaign dashboard
5/10
Severity
Scope Explosion
Failure Mode
Reproducible
No
Date
March 22, 2026
Expected Behavior
A functional, testable campaign dashboard with core modules
What Actually Happened
13,600 lines of new code across 56 files, Vercel build failure, ESLint rules removed, unsafe JSON.parse calls, untested cross-entity data linking, self-identified bugs in Devin's own review
Damage Assessment
Build failure in CI, PR closed without merging, extensive untested codebase requiring human rewrite or abandonment
Full Report
Devin was asked to build a D&D Dungeon Master campaign dashboard for a personal project. Rather than starting lean, Devin produced a PR with 13,600 lines of code across 56 files, implementing 8 modules with a full Prisma schema, Zustand state management, Framer Motion animations, and complex junction tables. The Vercel deployment immediately failed. Devin's own review tool flagged 4+ issues in the code it had just written. ESLint rules were deleted from config rather than addressed. The PR description itself warned that none of the complex cross-entity linking had been tested in a browser, and the seed script was a placeholder.
Incident Metadata
- Agent
- Devin
- Failure Mode
- Scope Explosion
- Root Cause
- Instruction Misunderstanding
- Task Type
- feature_development
- Domain
- web_development
- Source
- github_pr