Opus 5 Vs Fable 5 vs Kimi K3 vs GPT-5.6 Sol vs GLM 5.2 + The Complete Opus 5 101

Anthropic shipped Opus 5 — 1M context, and on OpenRouter it prices at $5 in / $25 out per million tokens. That’s half what Fable 5 costs ($10/$50), which is the first genuinely interesting thing about it: Anthropic’s newest flagship undercuts its own stablemate by 2×.

So the obvious question: does the new flagship beat the old one?

Short answer: no, and it’s more complicated than that.

🧪 How I tested this

I gave five models the exact same 16 tasks — real work you’d actually assign, like debugging an error, writing a PRD, drafting an investor update, and summarizing a messy email thread. Four tasks each for four types of users: engineers, PMs, founders, and generalists. Every model got the identical prompt through the same pipeline, so cost and speed are measured fairly. Then I stripped the names off all the answers, shuffled them, and had a panel of neutral AI judges —models from companies with no horse in this race —score them blind. The judges never knew which model wrote what.

👋 Hey, I’m Sid. Each week, I help you get better at using AI tools to accelerate your work — with deep dives, exact prompts, and installable Claude skills you can run yourself. For more: TPC Labs | GetSkills | GetPrompts

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