http://simonwillison.net/2026-09-11T17:47:11+00:00Simon Willison2026-09-11T17:47:11+00:002026-09-11T17:47:11+00:00https://simonwillison.net/2026/Sep/11/boris-cherny/

<blockquote cite="https://twitter.com/bcherny/status/2098217573276131577"><p>Production code written by Claude should have a higher bar than if it was written by a human. At Anthropic, we have many guardrails in place to make sure this is happening: lots of lint rules, lots of tests, Claude-driven end to end tests, Claude-powered fuzzers running daily, automated code reviews and security reviews, automated code refactoring, and so on. Without these, you can end up with a mess that is hard to maintain down the line.</p></blockquote> <p class="cite">&mdash; <a href="https://twitter.com/bcherny/status/2098217573276131577">Boris Cherny</a></p> <p>Tags: <a href="https://simonwillison.net/tags/ai">ai</a>, <a href="https://simonwillison.net/tags/generative-ai">generative-ai</a>, <a href="https://simonwillison.net/tags/llms">llms</a>, <a href="https://simonwillison.net/tags/ai-assisted-programming">ai-assisted-programming</a>, <a href="https://simonwillison.net/tags/anthropic">anthropic</a>, <a href="https://simonwillison.net/tags/claude">claude</a>, <a href="https://simonwillison.net/tags/coding-agents">coding-agents</a>, <a href="https://simonwillison.net/tags/claude-code">claude-code</a>, <a href="https://simonwillison.net/tags/agentic-engineering">agentic-engineering</a>, <a href="https://simonwillison.net/tags/boris-cherny">boris-cherny</a></p>

2026-07-25T00:42:59+00:002026-07-25T00:42:59+00:00https://simonwillison.net/2026/Jul/25/boris-cherny/

<blockquote cite="https://twitter.com/bcherny/status/2080713091688583312"><p>More than any of these eval scores, what is most exciting to me is something else: Opus 5 is our least prompt injectable model yet. It is a bit buried in the system card, but across PI evals and red teaming, Opus 5 is very hard to prompt inject successfully.</p></blockquote> <p class="cite">&mdash; <a href="https://twitter.com/bcherny/status/2080713091688583312">Boris Cherny</a>, here's that <a href="https://www-cdn.anthropic.com/c5fbac3f0b1280a933ebd26d3cb8bb9f5bdeaf48/Claude%20Opus%205%20System%20Card.pdf#page=73">System Card section</a>, page 73</p> <p>Tags: <a href="https://simonwillison.net/tags/ai">ai</a>, <a href="https://simonwillison.net/tags/prompt-injection">prompt-injection</a>, <a href="https://simonwillison.net/tags/generative-ai">generative-ai</a>, <a href="https://simonwillison.net/tags/llms">llms</a>, <a href="https://simonwillison.net/tags/anthropic">anthropic</a>, <a href="https://simonwillison.net/tags/claude">claude</a>, <a href="https://simonwillison.net/tags/boris-cherny">boris-cherny</a></p>

2026-02-14T23:59:09+00:002026-02-14T23:59:09+00:00https://simonwillison.net/2026/Feb/14/boris/

<blockquote cite="https://twitter.com/bcherny/status/2022762422302576970"><p>Someone has to prompt the Claudes, talk to customers, coordinate with other teams, decide what to build next. Engineering is changing and great engineers are more important than ever.</p></blockquote> <p class="cite">&mdash; <a href="https://twitter.com/bcherny/status/2022762422302576970">Boris Cherny</a>, Claude Code creator, on why Anthropic are still hiring developers</p> <p>Tags: <a href="https://simonwillison.net/tags/careers">careers</a>, <a href="https://simonwillison.net/tags/ai">ai</a>, <a href="https://simonwillison.net/tags/generative-ai">generative-ai</a>, <a href="https://simonwillison.net/tags/llms">llms</a>, <a href="https://simonwillison.net/tags/ai-assisted-programming">ai-assisted-programming</a>, <a href="https://simonwillison.net/tags/anthropic">anthropic</a>, <a href="https://simonwillison.net/tags/coding-agents">coding-agents</a>, <a href="https://simonwillison.net/tags/claude-code">claude-code</a>, <a href="https://simonwillison.net/tags/boris-cherny">boris-cherny</a></p>

2025-12-27T14:13:43+00:002025-12-27T14:13:43+00:00https://simonwillison.net/2025/Dec/27/boris-cherny/

<blockquote cite="https://twitter.com/bcherny/status/2004887829252317325"><p>A year ago, Claude struggled to generate bash commands without escaping issues. It worked for seconds or minutes at a time. We saw early signs that it may become broadly useful for coding one day.</p> <p>Fast forward to today. In the last thirty days, I landed 259 PRs -- 497 commits, 40k lines added, 38k lines removed. Every single line was written by Claude Code + Opus 4.5.</p></blockquote> <p class="cite">&mdash; <a href="https://twitter.com/bcherny/status/2004887829252317325">Boris Cherny</a>, creator of Claude Code</p> <p>Tags: <a href="https://simonwillison.net/tags/ai">ai</a>, <a href="https://simonwillison.net/tags/generative-ai">generative-ai</a>, <a href="https://simonwillison.net/tags/llms">llms</a>, <a href="https://simonwillison.net/tags/ai-assisted-programming">ai-assisted-programming</a>, <a href="https://simonwillison.net/tags/anthropic">anthropic</a>, <a href="https://simonwillison.net/tags/claude">claude</a>, <a href="https://simonwillison.net/tags/coding-agents">coding-agents</a>, <a href="https://simonwillison.net/tags/claude-code">claude-code</a>, <a href="https://simonwillison.net/tags/boris-cherny">boris-cherny</a></p>