--- title: Opus 5.5, Sonnet 5.5, and GPT-6.1 Sol: Choosing an AI... description: A hands-on comparison of newly released AI models—Opus 5.5, Sonnet 5.5, GPT-6.1 Sol, GPT-6 Astra, and GPT-6 Luna—for coding and agentic work. Opus 5.5 remains... canonical: https://daily.dev/posts/opus-5-5-sonnet-5-5-and-gpt-6-1-sol-choosing-an-ai-model-beyond-the-hype-h1be6wqxo twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: Opus 5.5, Sonnet 5.5, and GPT-6.1 Sol: Choosing an AI Model Beyond the Hype | daily.dev og:description: A hands-on comparison of newly released AI models—Opus 5.5, Sonnet 5.5, GPT-6.1 Sol, GPT-6 Astra, and GPT-6 Luna—for coding and agentic work. Opus 5.5 remains... og:url: https://daily.dev/posts/opus-5-5-sonnet-5-5-and-gpt-6-1-sol-choosing-an-ai-model-beyond-the-hype-h1be6wqxo og:image: https://api.daily.dev/og/posts/h1BE6WqxO.png og:image:alt: Opus 5.5, Sonnet 5.5, and GPT-6.1 Sol: Choosing an AI Model Beyond the Hype 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. # Opus 5.5, Sonnet 5.5, and GPT-6.1 Sol: Choosing an AI Model Beyond the Hype **[Medium](https://daily.dev/sources/medium_js)** · 8 min read · 1 upvotes · 0 comments ## Summary A hands-on comparison of newly released AI models—Opus 5.5, Sonnet 5.5, GPT-6.1 Sol, GPT-6 Astra, and GPT-6 Luna—for coding and agentic work. Opus 5.5 remains preferred for complex, sustained implementation due to strong judgment through ambiguity. GPT-6.1 Sol improved markedly for investigation and code review, with unchanged base pricing but lower cached-input cost, making it attractive for repeated analysis. Sonnet 5.5 is a solid upgrade for creative and well-defined tasks, but its lower nominal price can evaporate once cached-input usage or task length grows, since its cache-read rate matches Opus's. Astra remains useful for deep reasoning and computer-use tasks justifying its premium, while Luna suits high-volume repetitive work. The piece stresses evaluating total cost per acceptable result—including rework, supervision, and cache pricing—over raw benchmarks or sticker price. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Questions this post answers ### Which AI model is best for complex coding implementation, Opus 5.5 or Sonnet 5.5? Opus 5.5 is better suited for complex, sustained implementation because it shows stronger judgment through ambiguity and keeps progressing through multi-part codebase changes with less need for steering. Sonnet 5.5 performs well on creative and clearly defined tasks and can approach Opus's quality, but its nominal price advantage shrinks as context or token usage grows, since its cache-read rate matches Opus's. _Developers weighing implementation workloads across Claude models can track these trade-offs on daily.dev._ ### How does GPT-6.1 Sol's pricing compare to GPT-6 Sol for cached input? GPT-6.1 Sol keeps the same base input and output prices as the original GPT-6 Sol but lowers the cached-input rate, making repeated investigation and review work cheaper. It combines Sonnet's base input and output rates with half of Sonnet's cache-read rate, which makes it particularly cost-effective for workflows that repeatedly revisit instructions or codebase context. _Anyone budgeting agent token spend across model choices can follow pricing shifts like this on daily.dev._ ### Why might a cheaper AI model end up costing more for a coding task? A model with a lower nominal token price can still cost more overall if it needs more calls, a larger accumulated context, or more reasoning steps to finish the same task, since cache-read rates and total steps matter as much as the base price. The recommended measure is cost per acceptable result, factoring in token spend, retries, tool usage, and the time needed to inspect and correct output. _Teams comparing total cost of AI coding tools rather than sticker price can track this reasoning on daily.dev._ ## Similar posts on daily.dev - [OpenAI launches GPT-6 Sol and Luna, boasting lower cost and fewer mistakes](https://daily.dev/posts/openai-launches-gpt-6-sol-and-luna-boasting-lower-cost-and-fewer-mistakes-7fzpvatba) · TechCrunch · 0 upvotes · 0 comments --- Tags: [#llm](https://daily.dev/tags/llm), [#ai-coding](https://daily.dev/tags/ai-coding), [#claude](https://daily.dev/tags/claude), [#gpt](https://daily.dev/tags/gpt) [View this post on daily.dev](https://daily.dev/posts/opus-5-5-sonnet-5-5-and-gpt-6-1-sol-choosing-an-ai-model-beyond-the-hype-h1be6wqxo) ```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":"Opus 5.5, Sonnet 5.5, and GPT-6.1 Sol: Choosing an AI Model Beyond the Hype","url":"https://daily.dev/posts/opus-5-5-sonnet-5-5-and-gpt-6-1-sol-choosing-an-ai-model-beyond-the-hype-h1be6wqxo","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/opus-5-5-sonnet-5-5-and-gpt-6-1-sol-choosing-an-ai-model-beyond-the-hype-h1be6wqxo"},"datePublished":"2026-10-02T21:59:07.169Z","dateModified":"2026-10-02T22:07:15.753Z","description":"A hands-on comparison of newly released AI models—Opus 5.5, Sonnet 5.5, GPT-6.1 Sol, GPT-6 Astra, and GPT-6 Luna—for coding and agentic work. 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