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Claude Opus 4.5

anthropic.com

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Re: Claude Opus 4.5

#11

Post by stavros »

Did anyone else notice Sonnet 4.5 being much dumber recently? I tried it today and it was really struggling with some very simple CSS on a 100-line self-contained HTML page. This never used to happen before, and now I'm wondering if this release has something to do with it.

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.

EDIT 2: Apparently you can use `/model opusplan` to get Opus in planning mode. However, it says "Uses your extra balance", and it's not clear whether it means it uses the balance just in planning mode, or also in execution mode. I don't want it to use my balance when I've got a subscription, I'll have to try it and see.

EDIT 3: It looks like Sonnet also consumes credits in this mode. I had it make some simple CSS changes to a single HTML file with Opusplan, and it cost me $0.95 (way too much, in my opinion). I'll try manually switching between Opus for the plan and regular Sonnet for the next test.

Re: Claude Opus 4.5

#12

Post by 827a »

I've played around with Gemini 3 Pro in Cursor, and honestly: I find it to be significantly worse than Sonnet 4.5. I've also had some problems that only Claude Code has been able to really solve; Sonnet 4.5 in there consistently performs better than Sonnet 4.5 anywhere else.

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.

Re: Claude Opus 4.5

#15

Post by jmkni »

jumploops wrote: post #2

> Pricing is now $5/$25 per million [input/output] tokens 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!

> Pricing is now $5/$25 per million tokens

For anyone else confused, it's input/output tokens

$5 for 1million tokens in $25 for 1million tokens out

Re: Claude Opus 4.5

#16

Post by visioninmyblood »

827a wrote: post #12

I've played around with Gemini 3 Pro in Cursor, and honestly: I find it to be significantly worse than Sonnet 4.5. I've also had some problems that only Claude Code has been able to really solve; Sonnet 4.5 in there consistently performs better than Sonnet 4.5 anywhere else. 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…

The model is great it is able to code up some interesting visual tasks(I guess they have pretty strong tool calling capapbilities). Like orchestrate prompt -> image generate -> Segmentation -> 3D reconstruction. Checkout the results here https://chat.vlm.run/c/3fcd6b33-266f-4796-9d10-cfc152e945b7. Note the model was only used to orchestrate the pipeline, the tasks are done by other models in an agentic framework. They much have improved tool calling framework with all the MCP usage. Gemini 3 was able to orchestrate the same but Claude 4.5 is much faster

Re: Claude Opus 4.5

#17

Post by Squarex »

827a wrote: post #12

I've played around with Gemini 3 Pro in Cursor, and honestly: I find it to be significantly worse than Sonnet 4.5. I've also had some problems that only Claude Code has been able to really solve; Sonnet 4.5 in there consistently performs better than Sonnet 4.5 anywhere else. 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…

I have heard that gemini 3 is not that great in cursor, but excellent in Antigravity. I don't have a time to personally verify all that though.

Re: Claude Opus 4.5

#18

Post by alvis »

What surprise me is that Opus 4.5 lost all reasoning scores to Gemini and GPT. I thought it’s the area the model will shine the most

Re: Claude Opus 4.5

#20

Post by rishabhaiover »

827a wrote: post #12

I've played around with Gemini 3 Pro in Cursor, and honestly: I find it to be significantly worse than Sonnet 4.5. I've also had some problems that only Claude Code has been able to really solve; Sonnet 4.5 in there consistently performs better than Sonnet 4.5 anywhere else. 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…

I suspect Cursor is not the right platform to write code on. IMO, humans are lazy and would never code on Cursor. They default to code generation via prompt which is sub-optimal.
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