Fresh off the launch of Opus 5, Claude Code creator Boris Cherny joins Diana Hu at Startup School 2026 to talk about what the newest models can do, how Claude Code came to be, and what it means to build products when the underlying capabilities keep accelerating.
Transcript: https://www.ycrootaccess.com/p/boris-cherny-building-claude-code
Apply to Y Combinator: https://www.ycombinator.com/apply
Work at a startup: https://www.ycombinator.com/jobs
Chapters:
00:07 — What Makes Opus 5 Different
02:06 — Solving Prompt Injection
03:21 — Why Claude Code Deleted 80% of Its System Prompt
06:37 — Press Delete on Your AI Product
07:20 — How to Rebuild Your System Prompt
10:30 — Product Overhang and “Unhobbling” AI
14:26 — Give Claude Harder Problems
19:32 — Prompt Engineering Is Changing
21:57 — The Two-Week Claude Code Prompt
24:42 — Running Thousands of AI Agents
30:15 — Coding Is (Almost) Solved
32:20 — What Every CS Student Should Still Learn
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