The Pragmatic Engineer
The Pragmatic Engineer

Building Claude Code with Boris Cherny

March 4, 2026

AI Summary

5 min read

🎙️ The Voices & The Context

  • The Format: In-depth interview with storytelling, career anecdotes, and technical deep dives into AI coding tools.
  • The Key Players:
    • Boris Cherny: Engineering lead behind Claude Code at Anthropic; ex-Meta leader on code quality across Instagram/Facebook/WhatsApp; prolific coder who now ships 20-30 PRs/day with zero handwritten code.
    • Host (Gergely Orosz): Pragmatic Engineer podcaster, probing Boris's journey and AI workflows with insightful follow-ups.
  • The Vibe: Exciting & Educational—blends nostalgic hacker tales, mind-blowing AI demos, and futuristic optimism; high-energy "wow" moments on AI transforming engineering.

Continue reading the full summary in the app — free to try.

Read Full Summary →

Free • No credit card required

What you'll learn

  • 1 (00:00) **🎙️ Introduction: Boris Cherny**
  • 2 (01:08) **Early Entry into Coding and Startups**
  • 3 (07:00) **Meta Career: From Groups to Code Quality Leadership**
  • 4 (18:46) **Joining Anthropic and Claude Code Origins**
  • 5 (26:25) **Claude Code Adoption and Workflow Shift**
  • 6 (39:33) **Code Review in AI Era**
  • 7 (46:18) **Claude Code Architecture and Safety Layers**

+ Full timestamped outline available in the app

Show Notes

Brought to You By:

Statsig — ⁠ The unified platform for flags, analytics, experiments, and more.

Sonar – The makers of SonarQube, the industry standard for automated code review

WorkOS – Everything you need to make your app enterprise ready.

Boris Cherny is the creator and Head of Claude Code at Anthropic. He previously spent five years at Meta as a Principal Engineer and is the author of the book Programming TypeScript.

In this episode of Pragmatic Engineer, we went through how Claude Code was built and what it means when engineers no longer write most of the code themselves.

We discuss how Claude Code evolved from a side project into a core internal tool at Anthropic and how Boris uses it day-to-day. We go deep into workflow details, including parallel agents, PR structure, deterministic review patterns, and how the system retrieves context from large codebases. We also get into how Claude Cowork was built.

As coding becomes more accessible, the role of engineers shifts rather than shrinks. We examine what that shift means in practice, which skills become more important, and why the lines between product, engineering, and design are blurring.

Timestamps

(00:00) Intro

(11:15) Lessons from Meta

(19:46) Joining Anthropic

(23:08) The origins of Claude Code

(32:55) Boris's Claude Code workflow

(36:27) Parallel agents

(40:25) Code reviews

(47:18) Claude Code's architecture

(52:38) Permissions and sandboxing

(55:05) Engineering culture at Anthropic

(1:05:15) Claude Cowork

(1:12:48) Observability and privacy

(1:14:45) Agent swarms

(1:21:16) LLMs and the printing press analogy

(1:30:16) Standout engineer archetypes

(1:32:12) What skills still matter for engineers

(1:35:24) Book recommendations

The Pragmatic Engineer deepdives relevant for this episode:

How Claude Code is built

How Anthropic built Artifacts

How Codex is built

The Pragmatic Engineer