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Claude Opus 4.5

anthropic.com

161–170 of 525 posts

Re: Claude Opus 4.5

#161
post #50
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 really don’t understand the hype around Gemini. Opus/Sonnet/GPT are much better for agentic workflows. Seems people get hyped for the first few days. It also has a lot to do with Claude code and Codex.

with gemini you have to spend 30 minutes deleting hundreds of useless comments littered in the code that just describe what the code itself does

Re: Claude Opus 4.5

#162
post #5

Seeing these benchmarks makes me so happy. 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 squee…

I think we are at the point where you can reliably ignore the hype and not get left behind. Until the next breakthrough at least.

I've been using Claude Code with Sonnet since August, and there haven't been any case where I thought about checking other models to see if they are any better. Things just worked. Yes, requires effort to steer correctly, but all of them do with their own quirks. Then 4.5 came, things got better automatically. Now with Opus, another step forward.

I've just ignored all the people pushing codex for the last weeks.

Don't fall into that trap and you'll be much more productive.

Re: Claude Opus 4.5

#163

The burying of the lede here is insane. $5/$25 per MTok is a 3x price drop from Opus 4. At that price point, Opus stops being "the model you use for important things" and becomes actually viable for production workloads. 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 a…

3x price drop almost certainly means Opus 4.5 is a different and smaller base model than Opus 4.1, with more fine tuning to target the benchmarks. I'll be curious to see how performance compares to Opus 4.1 on the kind of tasks and metrics they're not explicitly targeting, e.g. eqbench.com

Why? They just closed a $13B funding round. Entirely possible that they're selling below-cost to gain marketshare; on their current usage the cloud computing costs shouldn't be too bad, while the benefits of showing continued growth on their frontier models is great. Hell, for all we know they may have priced Opus 4.1 above cost to show positive unit economics to investors, and then drop the price of Opus 4.5 to spur growth so their market position looks better at the next round of funding.

Re: Claude Opus 4.5

#164
post #17

Earlier quoted context omitted.

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.

I‘ve had no success using Antigravity, which is a shame because the ideas are promising, but the execution so far is underwhelming. Haven‘t gotten past an initial plannin doc which is usually aborted due to model provider overload or rate limiting.

Give it a try now, the launch day issues have gone.

If anyone uses Windsurf, Anti Gravity is similar but the way they have implemented walkthrough and implementation plan looks good. It tells the user what the model is going to do and the user can put in line comments if they want to change something.

Re: Claude Opus 4.5

#165
post #115

Earlier quoted context omitted.

If you're asking an LLM to compute something "off the top of its head", you're using it wrong. Ask it to write the code to perform the computation and it'll do better. Same with asking a person to solve something in their head vs. giving them an editor and a random python interpreter, or whatever it is normal people use to solve problems.

the decent models will (mostly) decide when they need to write code for problem solving themselves. either way a reply with a bogus answer is the fault of the provider and model, not the question-asker -- if we all need to carry lexicons around to remember how to ask the black box a question we may as well just learn a programming language outright.

Yes, Sonnet 4.5 tried like 10min until it had it. Way too long though.

Re: Claude Opus 4.5

#166
Does anyone here understand "interleaved scratchpads" mentioned at the very bottom of the footnotes:

> All evals were run with a 64K thinking budget, interleaved scratchpads, 200K context window, default effort (high), and default sampling settings (temperature, top_p).

I understand scratchpads (e.g. [0] Show Your Work: Scratchpads for Intermediate Computation with Language Models) but not sure about the "interleaved" part, a quick Kagi search did not lead to anything relevant other than Claude itself :)

[0] https://arxiv.org/abs/2112.00114

Re: Claude Opus 4.5

#167
post #5

Seeing these benchmarks makes me so happy. 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 squee…

Don't throw away what's working for you just because some other company (temporarily) leapfrogs Anthropic a few percent on a benchmark. There's a lot to be said for what you're good at. I also really want Anthropic to succeed because they are without question the most ethical of the frontier AI labs.

> I also really want Anthropic to succeed because they are without question the most ethical of the frontier AI labs.

I wouldn't call Dario spending all this time lobbying to ban open weight models “ethical”, personally but at least he's not doing Nazi signs on stage and doesn't have a shady crypto company trying to harvest the world's biometric data, so it may just be the bar that is low.

Re: Claude Opus 4.5

#168
post #50

Earlier quoted context omitted.

I really don’t understand the hype around Gemini. Opus/Sonnet/GPT are much better for agentic workflows. Seems people get hyped for the first few days. It also has a lot to do with Claude code and Codex.

with gemini you have to spend 30 minutes deleting hundreds of useless comments littered in the code that just describe what the code itself does

I haven't had a comment generated for 3.0 pro at all unless specified.

Re: Claude Opus 4.5

#170
post #140
post #100

Notes and two pelicans: https://simonwillison.net/2025/Nov/24/claude-opus/

i think you have an error there about haiku pricing > For comparison, Sonnet 4.5 is $3/$15 and Haiku 4.5 is $4/$20. i think haiku should be $1/$5

Fixed now, thanks.
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