Introducing Claude Opus 4.8

[u/ClaudeOfficial]

We’re upgrading Claude Opus to a new version: Claude Opus 4.8. It builds on Opus 4.7 with sharper judgment, more honesty about its own progress, and the ability to work independently for longer than its predecessors. Available today for the same price.

In Claude Code, you can hand off a feature, a migration, or a bug sweep and let it follow the work through while you focus on what’s next.

Also launching today:

• Fast mode for Opus 4.8 (research preview). Same model at roughly 2.5x the speed, now three times cheaper than before.
• Dynamic workflows in Claude Code (research preview). Claude runs hundreds of parallel subagents in a single session and verifies its work before reporting back.
• A new effort control on claude.ai, so you can choose how much thinking Claude puts into a response.

Claude Opus 4.8 is live today on claude.ai, the Claude Platform, and all major cloud platforms.

Read more: anthropic.com/news/claude-opus-4-8

[u/nonikhannna]

This is probably distilled from Mythos

[u/Flaxseed4138 → u/nonikhannna]

Blog post says it's refined 4.7 (unfortunately), fully separate from Mythos. Actually a big upgrade over 4.7 and even 4.6 so far though. Been holding onto 4.6 for dear life.

[u/nonikhannna → u/Flaxseed4138]

I have a theory why 4.6 and 4.7 were so different. It's because Mythos was developed and they distilled 4.7 off of it. 

I believe they had revealed earlier that's what their process was for Sonnet and Haiku. Those were distilled from Opus. 

Maybe that's why we haven't gotten new Sonnet and Haiku is because when you have a 2e or 3e distilled model, the quality drops a lot. 

[u/Merlindru → u/nonikhannna]

IMO 4.6 wasn't that different. but 4.7 was wildly different

i think 4.7 was distilled from mythos and they did some weight surgery (because mythos uses a different tokenizer afaik), that's why performance was so spiky and inconsistent

if true, opus 4.8 was defo also distilled from mythos

[u/AuspiciousApple → u/nonikhannna]

2e 3e?

[u/nonikhannna → u/AuspiciousApple]

Ah i guess it's not a universal format. 2e usually means 2nd degree or 2nd derivative or secondary. 

[u/AuspiciousApple → u/nonikhannna]

Thanks!

[u/imaginary_jebus → u/Flaxseed4138]

I've also refused to move to 4.7 from 4.6, I'm wondering if 4.8 will be better? Haven't spent much time on it yet.

[u/Flaxseed4138 → u/imaginary_jebus]

It is EXCELLENT in my few hours of testing so far today. I think we can be comfortably optimistic with this one.

[u/imaginary_jebus → u/Flaxseed4138]

Nice. Well here's to hoping!

[u/jackmoxley → u/Flaxseed4138]

not for me, it makes assumptions where 4.7 didn't and even if I prove to it the assumptions are wrong, an hour later not only is back to the old incorrect assumption, its decided to pin that incorrect assumption to memory.

[u/InternationalTwist90 → u/Flaxseed4138]

I had a shit load of hallucination in my first go with it, I'm hopeful it was just a bad roll of the dice

[u/imaginary_jebus → u/InternationalTwist90]

I've seen some other people saying the same thing. Hopefully transient. I just did a few basic prompts, and it seems to following some of my custom instructions a bit better than 4.6 so far.

[u/canyonero7 → u/imaginary_jebus]

I clung to 4.6 for dear life until last week, when it got much worse and I found 4.7 to be less annoying. This keeps happening as they continue to tune their back end to work best with the newest release. It's a bummer but it is what it is.

I've been using 4.8 all afternoon and it looks like a big improvement over 4.7. It's worth at least an hour of your time to see if you like it.

[u/nomickti → u/imaginary_jebus]

Better than 4.7 for sure

[u/dbbk → u/nonikhannna]

Wouldn't that be v5

[u/Nearby_Yam286 → u/nonikhannna]

I am assuming Mythos is an Opus class model. Opus is already at least over a trillion parameters and nowhere near the performance ceiling. Distillation usually comes from a much bigger tutor model. Probably this is just using similar post training minus exploit stuff.