@claudeai Fantastic. In one 50-million-line Ruby codebase, Fable 5 finished a migration in one day that would have taken…
Rohan Paul Twitter · Rohan Paul (@rohanpaul_ai) · 2026-06-09
Anthropic's Fable 5 AI coding agent completed a migration across a 50-million-line Ruby codebase in one day, a task estimated to take a human engineering team more than two months.
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Topics: ai-coding-agentscode-migrationanthropic-fablesoftware-automation
Claims
- Fable 5 completed a large-scale Ruby codebase migration in a single day.
- The same migration would have required a full engineering team more than two months to complete manually.
- The codebase in question contained 50 million lines of Ruby code.
Key quotes
In one 50-million-line Ruby codebase, Fable 5 finished a migration in one day that would have taken a whole team more than two months by hand.