UI Regression Fix Benchmark

Compared agents on finding and fixing a responsive CSS regression in an existing React app.

**Agents tested:** Cursor, Windsurf, Claude Code, Cline

**LLM used:** Claude 4 Sonnet

**Winner:** Cursor

Cursor won on speed because its Composer UI made it easy to point at the broken layout and apply a scoped fix. Cline was close but required more manual verification. Claude Code and Windsurf both fixed the issue but took longer to surface the right file.