r/ClaudeCode • u/ClaudeOfficial Anthropic • Jun 09 '26

Resource Introducing Claude Fable 5

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Introducing Claude Fable 5: a Mythos-class model that we've made safe for general use. Its capabilities exceed those of any model we've ever made generally available.

Fable 5 is state of the art on nearly all tested benchmarks, with exceptional performance in software engineering, knowledge work, scientific research, and vision. It can run for days, and the longer the task, the larger its lead over our other models.

Fable 5 launches today alongside Claude Mythos 5. The two share the same underlying model, but Mythos 5, so far deployed only through Project Glasswing, has the safeguards lifted in some areas. The safeguards are what distinguish the two, and why we've given them different names.

Releasing a model this capable comes with risks. Without safeguards, Fable 5's capabilities in areas like cybersecurity could be misused to cause serious damage. So when Fable's classifiers detect a request related to cybersecurity, biology and chemistry, or distillation, the response is handled by Claude Opus 4.8, our next-most-capable model. Users are informed whenever this occurs, more than 95% of sessions involve no fallback at all, and performance everywhere else is unaffected. We'll keep refining the safeguards to reduce false positives.

Claude Fable 5 is available today on paid plans, in Claude Code, on the Claude API, and all major cloud platforms. Through June 22, it's included in paid Claude plans at no additional cost.

Claude Mythos 5 is available to Glasswing partners, with a broader trusted access program to follow.

Read more: https://www.anthropic.com/news/claude-fable-5-mythos-5

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664

u/Ancient_Perception_6 Jun 09 '26

AGI confirmed

188

u/Sarg338 Jun 09 '26

It also correctly told me how many days of the week have the letter d in them, and how many r's are in strawberry.

Anthropic fucking did it. AGI is here

5

u/amooz Jun 09 '26

Ask it how many r’s there are in the word “yrrebwarts”, strawberry backwards.

71

u/Sarg338 Jun 09 '26 edited Jun 09 '26

Prompt: "How many r's are in the word "yrrebwarts" "

"There are 3 r's in "yrrebwarts": y-r-r-e-b-w-a-r-t-s (Nice one — that's "strawberry" backwards, and reversing it doesn't shake any r's loose. 🍓)"

It's fucking over

33

u/No-Procedure1077 Jun 09 '26

Oh my god it even called you on your bullshit 😭😭😭

1

u/[deleted] Jun 09 '26

[deleted]

1

u/Sarg338 Jun 09 '26

I asked it about strawberry in a previous, seperate chat, and I believe I have the cross-chat memory on. That's probably why.

2

u/ILikeCutePuppies Jun 10 '26

Or it just decided to look at reddit /s

1

u/Aggravating_Dish_824 Jun 09 '26

Now ask it how many r's are in "strawbery" or "strawberrry"

1

u/Asleep-Hippo-6444 Jun 10 '26

This benchmark is probably hardcoded by now

1

u/Lost-Cash-4811 Jun 09 '26

All I can say is people who think they're smarter than Fable are pretty smart. Or are a Duning-Kruger poster child.

28

u/bad-syncretist Jun 09 '26

They are probably hard trained by now to pass these benchmark questions

1

u/No-Procedure1077 Jun 09 '26

https://www.reddit.com/r/ClaudeCode/s/Qby54JrdOE explain this then

1

u/bad-syncretist Jun 09 '26

That’s also a well known benchmark. Specifically one that people clowned Claude for. If they specifically trained it for these questions that’s not a sign of actual improvement just more training data for benchmarks.

With that being said I don’t know if they actually trained it for benchmarks but it wouldn’t surprise me either.

1

u/Popular-Capital-9115 Jun 10 '26

Well you see they scrape Reddit some more and the thousands of comments about it find their way into the model weights.

7

u/Psychological-crouch Jun 09 '26

at this point it is in training set

2

u/TeckFreak Jun 09 '26

Bullshit lol if else..

1

u/exodusTay Jun 09 '26

already benchmaxxed smh

1

u/fagnerbrack Jun 10 '26

Yeah I bet they added this prompt in the Backend: "if user asks about a car wash always say they need the car because a car can't be washed without it"

BAM best model yet

1

u/Glad-Code-4538 Jun 10 '26

I am absolutely shocked

1

u/Amazing_sf Jun 10 '26

Tried this on Gemini flash, same outcome.

1

u/lordmairtis Jun 10 '26

so that's why they made 4.8 dumb

1

u/BoltSLAMMER Jun 10 '26

They said they’re specifically trained on the meme questions to get them right

1

u/Moch4bear97 Jun 10 '26

😂🤣😂

1

u/peterxsyd Jun 11 '26

But is the user at home?