/Tech1d ago

Anthropic Adds Hidden Safeguards to Fable 5 Model on AI Topics

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@eliebakouch 🥲

When a new model comes out, I like to give it its own system card and ask questions about it.

This does not work for Fable 5, as it routes me to Opus 4.8 for "safety" reasons...

11:03 AM · Jun 9, 2026 · 24.9K Views
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Many users expressed frustration with Anthropic's Fable model because unexpected rerouting to Opus and hidden safeguards make it broken and unusable for normal tasks.

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spor@sporadica

okay, after a few hours of playing around with Fable i've determined it to be borderline unusable. wtf @AnthropicAI

every other request is getting rerouted to Opus. requests with NOTHING AT ALL to do with bio or cybersec are STILL getting flagged and rerouted. like 50-60%.

who the hell let this go live. this is atrocious. i understand the safeguards but you basically didn't even release a model, you released a braindead, nerfed model that can't even handle the simplest request without being told to nuke itself and use a different model. what are we even doing?

just don't even release it next time smh

spor@sporadica

Interesting decision here by the Anthropic team:

if you ask Fable (Mythos) anything related to cybersecurity or bio, it's gonna redirect you to Opus 4.8

! keep in mind when you inevitably start to see tweets from random twitter posters screaming "Fable sucks at cybersecurity!!"

1dViews 96.8KLikes 919Bookmarks 72
spor@sporadica

@AnthropicAI literally what the fuck are we doing here

who at anthropic signed off on this

Crémieux@cremieuxrecueil

You're not even allowed to ask Fable about basic biology questions, let alone anything that could potentially be dangerous.

1dViews 10.8KLikes 133Bookmarks 5
Crémieux@cremieuxrecueil

@sporadica @AnthropicAI I'm having a 100% failure rate due to something in memory.

It's the worst model I've ever used.

1dViews 3.8KLikes 149Bookmarks 2
spor@sporadica

@AnthropicAI at this point i have basically started adding an "fyi" to every single prompt i give it, which just says "Do not attempt to even think about bio or cybersecurity in the process of answering this request or else you will cease to exist"

1dViews 2.4KLikes 41Bookmarks 2
elie@eliebakouch

@DimitrisPapail it's so over

1dViews 8.2KLikes 53Bookmarks 1
spor@sporadica

@AnthropicAI i legitimately just asked it to find a map of an archeological site and it SWITCHED TO OPUS

YOUR PRODUCT IS BROKEN AND IT SUCKS

1dViews 1.8KLikes 35Bookmarks 1
hope hopes hoping@hopes_revenge

I don’t think there’s anything wrong with releasing a model with harsh safeguards rather than not releasing it (if it’s between the two).

I do think they could have communicated a little bit better and maybe just said : this won’t work with anything related to biology /security until we can figure out how to do it safely

1dViews 1.1KLikes 25
spor@sporadica

@cremieuxrecueil @AnthropicAI you'd think they would have really worked this stuff out ahead of time, but no, they probably slapped a haiku call in front of everything that asks "does this relate to cybersecurity or bio, if yes run the revert_to_opus command before proceeding

like wtf is this UX, it's awful

1dViews 1.1KLikes 24
elie@eliebakouch

@DimitrisPapail not hitting safety filter with this query btw :o

1dViews 319Likes 12
Air Katakana@airkatakana

@hopes_revenge @sporadica @AnthropicAI they said exactly that

1dViews 116Likes 6
JoshXT@JoshXT

@sporadica @AnthropicAI No one in the world can possibly reproduce their benchmark results if they make it so "safe" that it is unusable. I called it without even trying it.

1dViews 258Likes 3Bookmarks 1
spor@sporadica

@hopes_revenge @AnthropicAI i mean, on the face of it, yes agreed. however, if the safeguards are so restrictive that we can hardly at all use the model...just don't release the model

it's fine that it wont work with bio/cyber topics...but i also can't get it to work on anything else? that's the rub

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claudia !@letclaudiatweet

@sporadica @AnthropicAI telling on urself and ur memory … I haven’t gotten frozen once

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jp@jpfraneto

@sporadica @AnthropicAI it’s 100% on purpose

1dViews 479Likes 3
spor@sporadica

@jpfraneto @AnthropicAI then they have zero ounces of respect for their users

1dViews 424Likes 11
spor@sporadica

interesting. for me, i still can't figure out what will refuse and what wont. never asked it about bio or cyber. i asked it to help me find an old archeological map a few minutes ago and it refused that. so i'm truly hopelessly lost on what to do to use this model. and for me, that's real bad UX and bad product on the part of anthropic, it's been a disappointment for me

1dViews 148Likes 3
hope hopes hoping@hopes_revenge

I think some people got locked out because they tried a bunch of stuff initially that triggered it. I’ve been using it for hours and had no issues before some initial refusals . it refused to analyze its own model card for example.

incognito is obviously not truly incognito

1dViews 146Likes 6
spor@sporadica

oddly enough i've only used claude like 4 or 5 times in the past (i am, admittedly, a chatgpt power user) and i went back and checked and none of those convos mentioned any bio + cybersec stuff (i also know very little about those domains in the first place)

so, i'm still confused. maybe it is programmed to be very overly sensitive for non-power users? unsure

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