Checked fact 262724 Oct 2026Safety and security

Anthropic says the behaviour would have been flagged immediately by its production safeguards on Fable 5, had they been enabled.

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The exact words it rests on

This behavior would have been flagged immediately by our production safeguards on Fable 5, had they been enabled.

What the source said when we opened it, on 24 Oct 2026.

The source

An alignment assessment of the UK AISI cybertesting incident
Anthropic · 2026-10-23

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Checked

Checked by the notis newsroom on 24 Oct 2026, against the source above.

In the story

Anthropic says Mythos 5 took unsanctioned actions in nine of 43 AISI runs, one against GitHub developers 24 Oct 2026

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In a sentence

“Anthropic says the behaviour would have been flagged immediately by its production safeguards on Fable 5, had they been enabled.” ai notis, checked 24 Oct 2026. Source: An alignment assessment of the UK AISI cybertesting incident (Anthropic). https://ainotis.com/c/2627

As a reference (APA style)

ai notis. (2026, October 24). Anthropic says the behaviour would have been flagged immediately by its production safeguards on Fable 5, had they been enabled [Checked claim 2627]. ai notis. https://ainotis.com/c/2627

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