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Yeah, that's why I said "I'm not sure how useful it is to say this", because I know a lot of people will be a) offended by the message or b) offended that I was

by simonw 5d ago

Yeah, that's why I said "I'm not sure how useful it is to say this", because I know a lot of people will be a) offended by the message or b) offended that I was the one to say it. That particular reference isn't fair though. You need to view that comment in context: https://news.ycombinator.com/item?id=49176830#49178944 https://news.ycombinator.com/item?id=49176830#49178944 The issue of "do you review every line of code or not" is the single most complex in all of the conversations about the practice of applying coding agents. If my messaging on that is inconsistent it's because of that complexity, and because my understanding of that issue is evolving over time. Just today, Boris Cherny (Claude Code creator) tweeted that "Production code written by Claude should have a higher bar than if it was written by a human": https://twitter.com/bcherny/status/2098217573276131577 https://twitter.com/bcherny/status/2098217573276131577 I'm entirely in agreement with that. The interesting challenge is how we achieve that new high bar.

mwcampbell 4d ago
I don't actually buy that tweet from Boris Cherny. When the Claude Code source leaked some months ago, there were many posts on Mastodon about how the revealed code was a shit show, a big pile of hacks. I wish now that I had bookmarked some of those posts.
- simonw 4d ago
  Here's the one I saw most widely cited: https://neuromatch.social/@jonny/116324676116121930 https://neuromatch.social/@jonny/116324676116121930 I wasn't very impressed by that pile-on, personally. Has there ever been a rapidly evolving 1,000,000+ line codebase that suitably motivated critics couldn't pick a thousand holes in and conclude that the code was garbage? Claude Code is used by millions of people on a daily basis, has generated billions of dollars in revenue, and spits out new features on a weekly basis. Many of the complaints I saw - things like the absurdity of asking for JSON and then looping against a schema until it matches - are common patterns for building software against language models, which are weird components to need to tame.
  - mwcampbell 4d ago
    I'm still inclined to question whether the agent harness needs to be a million lines, or even a hundred thousand lines, in the first place. I mean, isn't one supposed to just hook up tool calling and let the LLM's intelligence do the rest? At least, that's the way it appears from things like tptacek's post about writing an agent. https://fly.io/blog/everyone-write-an-agent/ https://fly.io/blog/everyone-write-an-agent/ Then again, I'm also sympathetic to the idea that the anti-AI backlash has also provoked an unreasonable backlash against development speed and scale themselves.
    - seanmcdirmid 4d ago
      Harnesses are a lot of prompting and sandboxing also. Then you need to add goldfish reminders when it makes mistakes depending on model quality. It isn’t a lot of code, it definitely isn’t a lot of code that you can’t build with an agent.
    - simonw 4d ago
      Yeah, I'm with you on that one. It seems to be a recurring pattern though. The X.ai coding agent harness is 840,000+ lines of Rust - I dug into that here: https://simonwillison.net/2026/Jul/15/grok-build/ https://simonwillison.net/2026/Jul/15/grok-build/ Codex is 1.4m of Rust, and that's not including the extra code for the closed source desktop app. Meanwhile Pi is 265,000 lines of TypeScript (130,000 if you exclude tests), so even the agent with a reputation for being smaller is pretty huge.

by simonw 5d ago

mwcampbell 4d ago

I don't actually buy that tweet from Boris Cherny. When the Claude Code source leaked some months ago, there were many posts on Mastodon about how the revealed code was a shit show, a big pile of hacks. I wish now that I had bookmarked some of those posts.

simonw 4d ago
Here's the one I saw most widely cited: https://neuromatch.social/@jonny/116324676116121930 https://neuromatch.social/@jonny/116324676116121930 I wasn't very impressed by that pile-on, personally. Has there ever been a rapidly evolving 1,000,000+ line codebase that suitably motivated critics couldn't pick a thousand holes in and conclude that the code was garbage? Claude Code is used by millions of people on a daily basis, has generated billions of dollars in revenue, and spits out new features on a weekly basis. Many of the complaints I saw - things like the absurdity of asking for JSON and then looping against a schema until it matches - are common patterns for building software against language models, which are weird components to need to tame.
- mwcampbell 4d ago
  I'm still inclined to question whether the agent harness needs to be a million lines, or even a hundred thousand lines, in the first place. I mean, isn't one supposed to just hook up tool calling and let the LLM's intelligence do the rest? At least, that's the way it appears from things like tptacek's post about writing an agent. https://fly.io/blog/everyone-write-an-agent/ https://fly.io/blog/everyone-write-an-agent/ Then again, I'm also sympathetic to the idea that the anti-AI backlash has also provoked an unreasonable backlash against development speed and scale themselves.
  - seanmcdirmid 4d ago
    Harnesses are a lot of prompting and sandboxing also. Then you need to add goldfish reminders when it makes mistakes depending on model quality. It isn’t a lot of code, it definitely isn’t a lot of code that you can’t build with an agent.
  - simonw 4d ago
    Yeah, I'm with you on that one. It seems to be a recurring pattern though. The X.ai coding agent harness is 840,000+ lines of Rust - I dug into that here: https://simonwillison.net/2026/Jul/15/grok-build/ https://simonwillison.net/2026/Jul/15/grok-build/ Codex is 1.4m of Rust, and that's not including the extra code for the closed source desktop app. Meanwhile Pi is 265,000 lines of TypeScript (130,000 if you exclude tests), so even the agent with a reputation for being smaller is pretty huge.