Anthropic lays out a six-step Claude Code playbook for migrating a 1M-line codebase
xiaohu · x · 2026-07-22
Anthropic published a practical six-step playbook for using Claude Code to migrate a production codebase from one language to another. The post says the team moved Bun’s one-million-line codebase from Zig to Rust in two weeks, and the article explains how they approached the migration end to end.
Key takeaways:
- The workflow was designed for a real production migration, not a toy refactor.
- Claude Code was used as an agentic coding assistant across the migration process.
- The post focuses on the operational steps and coordination needed to move a large codebase safely.
- It is framed as a repeatable method for handling large-scale language transitions with AI assistance.
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