Claude Code R&D Stories: From a Toy That Plays Music from Screenshots to Fully Automated Writing of Complete Code

According to Dongcha Beating monitoring, how did Claude Code—helping developers bid farewell to hand-coding—come to be? Anthropic has officially revisited the behind-the-scenes R&D story of this tool.

The R&D team had built an internal utility called clide back in 2023. Due to the limitations of the context window of traditional large models, when this tool needed to handle file directories beyond the window, it even had to launch 100 Claude Haiku models in parallel to read them—making it not only extremely slow to start, but also cluttered with complicated instructions.

In September 2024, Boris Cherny—who had just left Meta and is the author of Programming TypeScript—joined the lab team. He initially planned to break in by writing a simple code static checker (Linter), but at the urging and encouragement of his supervisor, he decided to go big: he developed a brand-new command-line tool from scratch and named it Claude CLI. In the earliest demo, the tool demonstrated the “magic” of directly controlling local system base commands—it could automatically take screenshots, read the Apple Music interface, and accurately identify what song Boris was listening to.

With the tremendous leap forward in the capabilities of the Claude 4 model, this originally toy-like tool suddenly surged into astonishing iteration speed. Because the command-line architecture is extremely lightweight and requires no maintenance of a complex web front end, the team could complete hot updates within minutes. With the public testing starting in February 2025, Claude CLI was officially renamed Claude Code. By the end of 2025, while Boris Cherny—who led the project—was lounging on the couch with his family, he used conversational commands to have Claude Code automatically submit 88 code commits in a single day. Both he and the core member Igor Kofman have achieved 100% of their code being written by Claude Code, with neither of them writing a single line of code themselves.