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At Startup School 2026 (video posted 2026-07-27), sdianahu hosted Boris Cherny…

2026-07-27 · 17:18 UTC ·@sdianahu ·1 min read

Brief

sdianahu’s Startup School 2026 session with Boris Cherny (Claude Code creator) covers Opus 5’s differences and a thesis of product overhang: startups should ship products that leverage unexplored inherent model capabilities. Cherny details prompt-injection defenses, deleting 80% of Claude Code’s system prompt, rebuilding prompts, a two-week prompt cycle, and scaling to thousands of agents.

Why it matters

At Startup School 2026 (video posted 2026-07-27), sdianahu hosted Boris Cherny (@bcherny), creator of Claude Code, to explain how Opus 5 changes product design and to argue startups should pursue the “product overhang” by shipping features that exploit inherent model capabilities nobody has explored.

Key details

  • Cherny revealed Claude Code deleted 80% of its system prompt, discussed defenses against prompt injection, the ‘Press Delete’ approach to rebuilding system prompts, a two-week Claude Code prompt iteration, running thousands of AI agents, and the claim that “coding is (almost) solved.”
Source evidence

here’s our talk @bcherny on how to build with frontier models

the big opportunity for startups is shipping products that use the inherent model capability nobody has explored yet

that’s the product overhang

Y Combinator (@ycombinator)

Fresh off the launch of Opus 5, Claude Code creator Boris Cherny (@bcherny) joins YC's @sdianahu 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.

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

@AnthropicAI @claudeai

Video

— https://nitter.net/ycombinator/status/2081787356420718704#m