# How Building Software Is Changing at Anthropic  ## Metadata - Author: [[The Pragmatic Engineer]] - Full Title: How Building Software Is Changing at Anthropic - Category: #articles - Summary: Anthropic uses advanced AI tools to build software faster and test code more thoroughly. Their teams plan carefully but prototype quickly by working closely with internal users. AI helps with code review, testing, and automating tasks, making development more efficient. ## Highlights - **Twelve-month project done in 11 days: Bun rewrite to Rust.** Migrating a 500K+ line project to another language used to take a small team a year, making it impractical. With Fable and $165K of tokens, it recently took the creator of the project less than two weeks. ([View Highlight](https://read.readwise.io/read/01kzm5a8bmgzbcxgjggt4ymgh5)) - **Changing engineering practices**. Inside the AI lab with more than 3,500 employees, prototyping is more fluid, verification is more time-consuming than implementation, code review and testing are increasingly done by AI. ([View Highlight](https://read.readwise.io/read/01kzm77wm3hrc3sm1nmhe9mrhj)) - **Team-level changes.** Design is more ongoing and less upfront, teams work on more projects, a maximum of two engineers per project, and more. ([View Highlight](https://read.readwise.io/read/01kzm786mpw5nxngfra3xva7q1)) - **Will AI replace software engineering?** The more hands-on software engineers get with AI at the lab, the less they fear their jobs are going away. ([View Highlight](https://read.readwise.io/read/01kzm78vargt1wq48anqk5pqcn))