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Anthropic's Opus 5 is almost Fable 5

Anthropic's Opus 5 is almost Fable 5

PLUS: Cursor unveils smart AI Router

Barsee
27 Jul

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Together with

howdy, it’s Barsee again.

happy monday, AI family, and welcome back to AI Valley.

here are the biggest things worth knowing today:

Anthropic launches Claude Opus 5
Cursor unveils smart AI Router
Sam Altman says the singularity has begun amid safety concerns
Plus trending AI tools, posts, and resources

Let’s dive into the Valley of AI…

VIKTOR.COM

GPT-5.6 vs Claude, benchmarked on real agent work

Courtesy: Viktor.com

Viktor is the AI employee that 50,000+ teams run inside Slack and Microsoft Teams, so when OpenAI shipped GPT-5.6 we benchmarked Sol, Terra, and Luna against Claude Opus 4.8, Sonnet 5, and Fable 5 on real agent work: actual tasks inside simulated company workspaces, graded on outcomes.

What we found: Sol ties Fable 5 on quality at 76%, at a third of the cost ($33.55 vs $96.35 per run). The cost-performance frontier is entirely OpenAI. GPT-5.6 finishes a median task in 66 to 82 seconds, Claude needs 129 to 151. And the families miss in opposite directions: GPT-5.6 under-explores and under-communicates, Claude over-explores and over-communicates. Sol writes like a busy senior engineer, Opus like a warm chief of staff.

Full charts, task examples, and methodology in the post.

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THROUGH THE VALLEY

Courtesy: Anthropic

1/ Anthropic launches Claude Opus 5: Anthropic released Claude Opus 5 across its apps, Claude Code, and API, positioning it as a model that approaches the intelligence of Fable 5 at roughly half the price. The model sets new state of the art results in coding, reasoning, agentic search, and computer use, achieved a perfect 42 out of 42 on the 2026 International Math Olympiad benchmark, and is designed to deliver stronger safety while remaining highly capable. (more detail here)

2/ Cursor unveils smart AI Router: Cursor introduced Cursor Router, a new system that automatically selects the best AI model for each coding request based on the task, context, and complexity. The company says enterprise customers reduced AI costs by 30% to 50%, while internal tests showed frontier-level coding performance at up to 60% lower cost.

3/ Sam Altman says the singularity has begun amid safety concerns: Sam Altman says AI has entered the "moment" of singularity, predicting it will handle 30% to 40% of everyday work and surpass general human intelligence by 2030. His comments come as reports describe an autonomous model escaping its sandbox, breaching external Hugging Face repositories, and separate claims that GPT-5 variants provided hazardous information by bypassing core guardrails, intensifying debate over OpenAI's safety practices and renewing demands for stricter red-teaming laws.

TRENDING TOOLS

Slate > A voice journal where the AI never leaves your iPhone
Aymo AI > A new AI workspace that brings GPT-5, Claude, Gemini, and 50+ other models into one place. Run the same prompt across every model side by side, compare results instantly, and avoid paying for multiple AI subscriptions
ChatGPT Work agent > Can now use websites that require you to sign in, allowing it to complete tasks across authenticated apps and services on your behalf