Anthropic releases Claude Opus 5 — near-Fable-5 intelligence at half the price
Claude Opus 5 (`claude-opus-5`) launched on July 24, 2026 at $5/$25 per million tokens. Anthropic said it comes close to Fable 5's frontier intelligence at half the price and sets new highs on Frontier-Bench v0.1 and GDPval-AA. Developers soon complained it was verbose and prone to over-engineering, which Opus 5.5 set out to fix two months later.
Key facts
- Released July 24, 2026; model id claude-opus-5; $5 input / $25 output per 1M tokens; fast mode 2x base price for ~2.5x speed
- Context 1M tokens (default and max), 128K output; thinking on by default
- Frontier-Bench v0.1: more than doubles Opus 4.8's performance; CursorBench 3.2 within 0.5% of Fable 5 at half the cost (Anthropic)
- Anthropic reports an ARC-AGI-3 score 3x higher than the next-best model (exact number not captured)
- Default model on Claude Max; cybersecurity classifiers intervene 85% less often than on Fable 5
- Anthropic called it its 'most aligned model to date' on the behavioral audit
What happened
Opus 5 upgrades Opus 4.8 with gains in agentic coding, computer use and long-horizon knowledge work. It is much better at verifying its own work and iterating until it succeeds. New API betas arrived with it: changing tools mid-conversation and automatic fallback to alternative models. It remained behind Mythos 5 on cyber exploitation and biology research.
Reception was mixed. Commentators such as MindStudio reported developer complaints that it was verbose, turned small fixes into large rewrites, and flagged trivial issues as urgent.
Why it matters
Opus 5 brought most of Fable 5's capability to half the price. Its reception problems explain why Opus 5.5's launch messaging stressed clear, concise communication.
Changelog
- 2026-09-29: created
Videos (6)
NEW Sonnet 5.5 Is Opus 5 Level
Mehul Mohan · 2026-09-29 · communitySoftware engineer Mehul Mohan reviews Anthropic’s release of Claude Sonnet 5.5, analyzing its benchmark performance, pricing structure, and positioning within the Claude 5.5 family. He demonstrates using Sonnet 5.5 in Claude Code to implement a privacy toggle on his custom financial trading dashboard, highlighting…
pdoom — Claude Opus 5
uncanny-fyi · 2026-09-10 · ai-madeThis animated short parodies The Joe Rogan Experience in a fictional podcast titled The Experience (Episode 2847), featuring host Joe interviewing an unnamed Large Language Model ("The Guest") about the concept of $p(\text{doom})$. Produced as an AI-generated animation and dialogue piece uploaded by uncanny-fyi, the…
2040-agi — Claude Opus 5
uncanny-fyi · 2026-09-09 · ai-madePresented as an episode of the retrospective radio documentary podcast Open Circuit (Episode 412, dated 14 March 2040), hosts Theo Brandt and Nadia Okonjo-Reyes narrate the simulated history of artificial general intelligence from the mid-2020s through 2040. Through dramatized interviews with synthetic researchers…
I Tested Fable 5.1 vs Fable 5 vs Opus 5 (Cost/Speed/Design)
Brock Mesarich | AI for Non Techies · 2026-09-08 · reviewIn this video, presenter Brock Mesarich conducts a hands-on benchmark comparing Anthropic's Claude Fable 5.1 against Claude Fable 5, Claude Opus 5, and OpenAI's Codex Sol / Terra models. He evaluates each model across three effort tiers (Low, High, and Max) on the same multi-step task: generating photorealistic…
Claude Opus 5 is a freak
AI Search · 2026-07-31 · communityThis video is a comprehensive review and benchmark critique of Anthropic’s Claude Opus 5 model, presented by the tech channel AI Search. The creator tests Opus 5’s agentic and vibe-coding capabilities across full-stack browser application design, 3D asset generation, motion graphics video production, DAW music…
Anthropic Just Revealed How to Prompt Opus 5
Paul J Lipsky · 2026-07-31 · tutorialIn this tutorial, presenter Paul J Lipsky reviews Anthropic's official prompting documentation for the newly released Claude Opus 5. He explains how to select appropriate models and reasoning effort settings across subscription tiers, and outlines five core prompting rules to optimize Opus 5 for knowledge work and…
Related posts (2)
- Beyond the pelican test: Opus 5 renders the Lord of the Rings opening in Three.js Andrej Karpathy @karpathy · x · 2026-08-02
Karpathy's most-liked post of summer 2026 (~29K likes) reframed how people informally test frontier models, using Claude Opus 5 with a 1M-token budget. - Introducing Claude Opus 5 Claude @claudeai · x · 2026-07-24
Launch post for Opus 5, pitched as close to Fable 5 at half the price; its mixed reception led to Opus 5.5's writing fixes.
Related events
- Anthropic releases Claude Opus 5.5 — Fable-5.1-level performance at $4/$20, first model of the Claude 5.5 family ★★★★★
- Anthropic releases Claude Fable 5 and Claude Mythos 5 — first generally available Mythos-class model ★★★★★
- Anthropic releases Claude Opus 4.8 with cheaper fast mode and Claude Code "dynamic workflows" ★★★
Sources (8)
- officialIntroducing Claude Opus 5 (Anthropic)
- paperClaude Opus 5 System Card (PDF)
- docsClaude Opus 5 docs overview
- pressTechCrunch: Anthropic launches Opus 5
- pressAxios: Anthropic releases new model, Opus 5
- press9to5Mac: Anthropic upgrades Claude with Opus 5
- discussionSimon Willison: Introducing Claude Opus 5
- discussionMindStudio: Why is Opus 5 getting bad reviews despite top benchmarks?
id: 2026-07-24-claude-opus-5 · updated 2026-09-29 · open in the interactive timeline