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Simon Willison

What Simon Willison thinks about Anthropic

@simon-willison · 57 positions · On ppll ↗

Co-creator of Django and creator of Datasette; writes daily at simonwillison.net.

Simon Willison did not write this page.

We collected these quotes from things they published elsewhere, and every quote links to where it was said. They have no account here and have not endorsed this site. Quotes are word for word; the short line under each one is our own restatement, not their wording. Their own site. Is this you? Claim it or ask us to remove it. Or tell us what is wrong here.

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Only Simon Willison on Anthropic. See everyone on Anthropic

11 dated positions, 2025 to 2026, in their own words. Our reading of what Simon Willison has said — not written or endorsed by them.

  1. Our readingIf Anthropic's revenue figures are accurate, other labs are spending more than half a billion dollars to distill Anthropic's models.

    Their wordsIf true, and Q2 revenue was $11.5B, then that's more than half a billion dollars spent by other labs to distill Anthropic's models!

    ↗@simonw on Xx.com

  2. 8 days earlier

  3. Our readingAnthropic's new credit scheme goes some way to overcoming the difference with OpenAI's Codex subscription deal.

    OpenAI

    Their wordsThis new credit scheme goes at least some way to overcoming that difference.

    ↗Introducing Claude Haiku 5.5simonwillison.net

  4. 2 weeks earlier

  5. Our readingClaude Opus 5.5's "max" thinking level may be effectively useless, since it over-thinks to breaking point even on a simple SVG prompt.

    Their wordsThis makes me suspect that “max” is effectively useless—if it over-thinks to breaking point on a stupid SVG prompt I don’t trust it not to do the same for more interesting work.

    ↗Claude Opus 5.5, GPT-6 Sol, GPT-6 Luna, and a new price warsimonwillison.net

  6. 3 weeks earlier

  7. Our readingClaude shouldn't be trusted to summarize its own system prompts when material in them might impact its opinions.

    Their wordsI don’t trust Claude to summarize its own system prompts when there’s a risk that material from its system prompt might impact its opinions.

    ↗Claude's new system prompt really doesn't want to reproduce song lyricssimonwillison.net

  8. 3 weeks earlier

  9. Our readingClaude Haiku hallucinates badly enough that its use inside Claude Code's WebFetch tool is a hallucination risk on every fetched URL.

    OpenAI

    Their wordsClaude Haiku is my current least favorite model - it hallucinates wildly, and is out-performed now by other similarly priced models like GPT-5.6-Luna Even worse: it seems to still be used by the Claude Code WebFetch tool, which means hallucination risk any time you fetch a URL!

    ↗@simonw on Xx.com

  10. 4 months earlier

  11. Our readingClaude has surprisingly good design taste for SwiftUI applications.

    designtaste

    Their wordsClaude has surprisingly good design taste when it comes to SwiftUI applications.

    ↗Vibe coding SwiftUI apps is a lot of funsimonwillison.net

  12. 8 days earlier

  13. Our readingTrusting model-written code you have not read became defensible only with Opus 4.5, and only for classes of problem you have already watched a model handle.

    Their wordsI think Opus 4.5 was the first one that earned my trust. Like I'm very confident now that for classes of problems that I've seen it tackle before, it's not going to do anything stupid.

    ↗Simon Willison: Engineering practices that make coding agents work - The Pragmatic Summityoutube.com 2nd of 18 in this recording

  15. Our readingThe frontier labs optimise their models for code above everything else because coding is where the money is: developers will pay $200 a month once a model is good enough.

    OpenAI

    Their wordsOpenAI and Anthropic have both realized that code is the most important thing to optimize the models for, cuz that's where the money is. Like coders will spend $200 a month on a plan if it's good enough, it turns out.

    ↗Simon Willison: Engineering practices that make coding agents work - The Pragmatic Summityoutube.com 13th of 18 in this recording

  17. Our readingThe interesting question is not what the next model will be able to do, but what the models already released can do that nobody has worked out yet.

    Their wordsI think the most interesting question is what can the models we have do right now? And so the only thing I care about today is what can Claude Opus 4.6 do that we haven't figured out yet. And I think it will take us 6 months to even start exploring the boundaries of that.

    ↗Simon Willison: Engineering practices that make coding agents work - The Pragmatic Summityoutube.com 14th of 18 in this recording

  19. Our readingDemand for open-source component libraries is collapsing, because a model will write exactly the widget you want instead of one you have to customise.

    Their wordsWhy would I use a date picker library where I'd have to customize it when I could have Claude write me the exact date picker that I want.

    ↗Simon Willison: Engineering practices that make coding agents work - The Pragmatic Summityoutube.com 17th of 18 in this recording

  20. 12 months earlier

  21. Our readingClaude tends to have good default taste in web page design.

    designtaste

    Their wordsI tend to find Claude has good default taste when it comes to web page design

    ↗Here’s how I use LLMs to help me write codesimonwillison.net