Boris Cherny: How Tool Use Turned a CLI Into Claude Code

By betting on bash tools and a minimal terminal loop; CLAUDE.md emerged from organic user demand, and subagents now parallelize repo exploration.

Boris ChernyguestGarry TanhostJared Friedmanhost

Feb 17, 202650mWatch on YouTube ↗

EPISODE INFO

Released: February 17, 2026
Duration: 50m
Channel: Y Combinator
Watch on YouTube: ▶ Open ↗

EPISODE DESCRIPTION

A very special guest on this episode of the Lightcone! Boris Cherny, the creator of Claude Code, sits down to share the incredible journey of developing one of the most transformative coding tools of the AI era. 00:00 Intro 01:45 The most surprising moment in the rise of Claude Code 02:38 How Boris came up with the idea for Claude Code 05:38 The elegant simplicity of terminals 07:09 The first use cases 09:00 What’s in Boris’ CLAUDE.md? 11:29 How do you decide the terminal’s verbosity? 15:44 Beginner’s mindset is key as the models improve 18:56 Hyper specialists vs hyper generalists 21:51 The vision for Claude teams 23:48 Subagents 25:12 A world without plan mode? 28:38 Tips for founders to build for the future 30:07 How much life does the terminal still have? 30:57 Advice for dev tool founders 32:11 Claude Code and TypeScript parallels 35:34 Designing for the terminal was hard 37:36 Other advice for builders 40:31 Productivity per engineer 41:36 Why Boris chose to join Anthropic 44:46 How coding will change 46:22 Outro Apply to Y Combinator: https://www.ycombinator.com/apply Work at a startup: https://www.ycombinator.com/jobs

SPEAKERS

Boris Cherny
guest
Garry Tan
host
Jared Friedman
host

EPISODE SUMMARY

In this episode of Y Combinator, featuring Boris Cherny and Garry Tan, Boris Cherny: How Tool Use Turned a CLI Into Claude Code explores inside Claude Code: terminals, tool-use, iteration, and model-driven design Claude Code began as Boris’s quick-and-cheap terminal chat client to learn the Anthropic API, then became powerful once tool use (bash) revealed the model’s drive to interact with the real world.

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