Building Claude Code: How Boris Cherny Ships 30 PRs a Day With Parallel Agents

Building Claude Code: From Side Project to Core Tool at Anthropic

TLDR: Boris Cherny, the creator of Claude Code and former Principal Engineer at Meta, walks through how Claude Code evolved from an internal side project into a core engineering tool at Anthropic. He reveals his workflow of running five parallel Claude instances to ship 20-30 PRs a day, and explains why plain glob and grep beat every fancy RAG approach for agentic code search.

Building Claude Code with Boris Cherny

Lessons From Meta: Code Quality and Engineering Culture

TLDR: Boris Cherny spent five years at Meta as a Principal Engineer, where he led causal analysis proving that clean codebases have a measurable impact on engineering productivity. His experience at Instagram -- where the Python/Django stack was so broken that click-to-definition did not work -- shaped his philosophy of fixing infrastructure before building products.

Inside Meta's Engineering Culture

The Shifting Role of Engineers in the Age of AI Coding

TLDR: As coding becomes more accessible through AI tools, Boris argues that the role of engineers shifts rather than shrinks. He compares today's software engineers to medieval scribes who became writers after the printing press, and suggests that generalists who can context-switch rapidly across parallel agents will thrive.

How Claude Code is built