AI agents refactored 300K lines of code in three weeks for $4,000

CodeScene published a case study in which coding agents refactored a 300,000-line C codebase over three weeks for roughly $4,000 in tokens. The work produced 2,903 commits across 726 files, modified 252,055 lines, and raised the Code Health score from 5.6 to 10.0, with Claude Opus doing most of the work.

• 2,903 commits across 726 files, 252,055 lines modified
• Code Health rose from 5.6 to 10.0 at roughly $4,000 in token cost
• Agents accumulated a playbook of 22 refactoring recipes and 82 notes
• Claude Opus with Claude Code outperformed Codex with Sol on the task