--- title: The Best Models Are Still Non-Deterministic | daily.dev description: LLMs, unlike compilers, are non-deterministic abstractions — meaning they don't behave consistently even given identical inputs and context. A concrete example... canonical: https://daily.dev/posts/the-best-models-are-still-non-deterministic-qdhvchusa twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: The Best Models Are Still Non-Deterministic | daily.dev og:description: LLMs, unlike compilers, are non-deterministic abstractions — meaning they don't behave consistently even given identical inputs and context. A concrete example... og:url: https://daily.dev/posts/the-best-models-are-still-non-deterministic-qdhvchusa og:image: https://api.daily.dev/og/posts/QdhvCHUSA.png og:image:alt: The Best Models Are Still Non-Deterministic og:image:width: 1200 og:image:height: 630 og:locale: en --- > ## Documentation Index > Fetch the complete documentation index at: https://daily.dev/llms.txt > Use this file to discover all available pages before exploring further. # The Best Models Are Still Non-Deterministic **[NeetCode](https://daily.dev/sources/neetcode)** · 1 min read · 8 upvotes · 0 comments ## Summary LLMs, unlike compilers, are non-deterministic abstractions — meaning they don't behave consistently even given identical inputs and context. A concrete example illustrates this: when using Claude with a tool called Fable, the same 'port already taken' situation can produce two completely different responses across separate chats, sometimes reusing the existing port and sometimes spinning up a new app instance. This unpredictability is a fundamental property of current LLMs, not just a maturity issue, and it means developers cannot treat AI coding tools as reliable, deterministic abstractions the way they treat compilers. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Similar posts on daily.dev - [Nondeterminism's not the problem](https://daily.dev/posts/nondeterminism-s-not-the-problem-pvu9jlh8e) · Lobsters · 1 upvotes · 0 comments - [LLMs could be, but shouldn't be compilers](https://daily.dev/posts/llms-could-be-but-shouldn-t-be-compilers-cwutlxyzi) · Hacker News · 1 upvotes · 1 comments --- Tags: [#llm](https://daily.dev/tags/llm), [#ai-coding](https://daily.dev/tags/ai-coding) [View this post on daily.dev](https://daily.dev/posts/the-best-models-are-still-non-deterministic-qdhvchusa) ```json {"@context":"https://schema.org","@graph":[{"@type":"Organization","@id":"https://daily.dev/#organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180},"sameAs":["https://twitter.com/dailydotdev","https://github.com/dailydotdev","https://www.linkedin.com/company/daily-dev-ltd"]},{"@type":"WebSite","@id":"https://daily.dev/#website","url":"https://daily.dev","name":"daily.dev","publisher":{"@id":"https://daily.dev/#organization"},"potentialAction":{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https://daily.dev/search?q={search_term_string}"},"query-input":"required name=search_term_string"}}]} {"@context":"https://schema.org","@type":"TechArticle","headline":"The Best Models Are Still Non-Deterministic","url":"https://daily.dev/posts/the-best-models-are-still-non-deterministic-qdhvchusa","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/the-best-models-are-still-non-deterministic-qdhvchusa"},"datePublished":"2026-07-22T14:47:03.439Z","dateModified":"2026-07-22T16:21:07.671Z","description":"LLMs, unlike compilers, are non-deterministic abstractions — meaning they don't behave consistently even given identical inputs and context. 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