So it’s 1/3 the price of Opus 4.1…

> [..] matches Sonnet 4.5’s best score on SWE-bench Verified, but uses 76% fewer output tokens

…and potentially uses a lot less tokens?

Excited to stress test this in Claude Code, looks like a great model on paper!

Not because I love Anthropic (I do like them) but because it's staving off me having to change my Coding Agent.

This world is changing fast, and both keeping up with State of the Art and/or the feeling of FOMO is exhausting.

Ive been holding onto Claude Code for the last little while since Ive built up a robust set of habits, slash commands, and sub agents that help me squeeze as much out of the platform as possible.

But with the last few releases of Gemini and Codex I've been getting closer and closer to throwing it all out to start fresh in a new ecosystem.

Thankfully Anthropic has come out swinging today and my own SOP's can remain in tact a little while longer.

On-topic, I love the fact that Opus is now three times cheaper. I hope it's available in Claude Code with the Pro subscription.

EDIT: Apparently it's not available in Claude Code with the Pro subscription, but you can add funds to your Claude wallet and use Opus with pay-as-you-go. This is going to be really nice to use Opus for planning and Sonnet for implementation with the Pro subscription.

However, I noticed that the previously-there option of "use Opus for planning and Sonnet for implementation" isn't there in Claude Code with this setup any more. Hopefully they'll implement it soon, as that would be the best of both worlds.

I think Anthropic is making the right decisions with their models. Given that software engineering is probably one of the very few domains of AI usage that is driving real, serious revenue: I have far better feelings about Anthropic going into 2026 than any other foundation model. Excited to put Opus 4.5 through its paces.

Also notable: they're claiming SOTA prompt injection resistance. The industry has largely given up on solving this problem through training alone, so if the numbers in the system card hold up under adversarial testing, that's legitimately significant for anyone deploying agents with tool access.

The "most aligned model" framing is doing a lot of heavy lifting though. Would love to see third-party red team results.

I’ve always found Opus significantly better than the benchmarks suggested.

LFG