Anthropic shipped Opus 5.5 a couple weeks back. I waited for the independent numbers before saying anything, and they're in. Artificial Analysis, who test everyone on the same harness instead of taking vendor word for it, now rank it first on their Intelligence Index at 58. GPT-6 Astra and Fable 5.1 are tied behind it at 53. They called it the highest score they've measured by several points. It also got cheaper. $4 per million input, $20 output, down from $5 and $25. Remember the Grok post a couple weeks ago? Same price per token, but it burned double the tokens, so the real cost per job went up. 📉 This is the opposite case, and it's worth understanding properly, because the honest version is more interesting than the headline. Opus 5.5 also uses more tokens than Opus 5 did. About 1.6 times more at maximum effort. But the price came down enough to absorb it, so Artificial Analysis found cost per task landed roughly level with Opus 5, while the score went from 51 to 58. Flat cost, meaningfully better output. That's the actual trade, and it's a good one. Just not the same thing as "40% cheaper," which is Anthropic's number for typical workloads at default settings, not what you'll see if you run everything at max. Now the number I'd actually act on. 💸 Cache reads dropped from 50 cents per million tokens to 20 cents. That's a 60% cut. If you run agents, that's your biggest line item and you probably don't think about it. Every turn an agent takes, it re-reads the same system prompt, the same tool definitions, the same conversation history. A 500,000 token context that cost 25 cents to re-read on Opus 5 now costs 10 cents. Nothing about that gets offset by token burn. It's just cheaper. Two more things worth knowing. Anthropic raised the five-hour limits on Pro, Max and Team at the same time, and gave subscribers a one-time rate limit reset they could trigger themselves. If you read my post about the weekly limits dropping in September, this softens that a bit. And there's a Fast mode in Claude Code at $8 and $40 for up to two and a half times the speed, if you're sitting there waiting on it.