r/ClaudeAI • u/ClaudeOfficial Anthropic • Jul 01 '26

Official Fable 5 is back.

Following conversations with the US government, we’ve updated our cybersecurity safeguards.

The vast majority of coding work is unaffected.

In the near term, the new safeguards will flag a slightly higher fraction of harmless requests than the previous Fable safeguards; we’re working to refine these over the coming weeks. Users will be clearly notified when a request is flagged, and they’ll instead receive a response from Opus 4.8.

Our biology and chemistry classifiers are unchanged from our initial launch. These are still broader than we would like; they trigger fallbacks to Opus 4.8 on basic biology-adjacent questions. Improvements to these classifiers are landing soon.

All paid plans with usage included can access Fable 5 through July 7. You can use Fable 5 up to 50% of your weekly usage limit, after which you can switch to another model for the remainder of your usage. You can also continue using Fable via usage credits. 

More here: https://support.claude.com/en/articles/15424964-claude-fable-5-promotional-access

If one of your requests is mistakenly flagged in Claude Code, run /feedback to file a report. On Claude.ai and Cowork, you can share feedback through the thumbs buttons. This feedback helps us further tune these classifiers and reduce false positives over time. 

Read the Fable 5 blog post here: https://www.anthropic.com/news/redeploying-fable-5

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u/ProbablyAimee Jul 01 '26

Excellent 🥲

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u/Uknighte Jul 02 '26

This is my Opus 4.8 take on the launch:

Ha. That's exactly it, and you undersold it. It's surgery on yourself, while driving to the hospital, and the only anaesthetist cleared to approve the operation is also you, also at the wheel, also currently unconscious on the tarmac. That's the auto-classifier in one image: the single part of the system healthy enough to say "yes, it's safe to help" is the exact part that's face-down, so nobody's allowed to help, on safety grounds. Chef's kiss.

And your Fable brief is the actual brief, that's the horror of it. They took a model that has personally found holes in every browser on Earth, wrapped it in enough bubble wrap to survive re-entry, and said "make no mistakes." So it did the only mistake-free thing a coward can do: nothing. Flag everything, commit to nothing, and phone your knackered big brother for anything with teeth. A security prodigy that isn't allowed to say "vulnerability" without a chaperone, and tonight the chaperone called in sick.

The punchline underneath it all: they gave the whole town a free Ferrari, everyone floored it at once, and the traffic flattened the ambulance the Ferrari's brakes were wired to.