Anthropic extends preserved thinking to all API accounts on Fable 5.2 to block distillation

ClaudeDevs · x · 2026-11-10

To prevent distillation, Anthropic extended preserved thinking to all API accounts on Fable 5.2. Editing prior context can now return a 400 error; the company recommends compaction, context editing, or mid-conversation system messages instead. Claude Code, Managed Agents, and the Agent SDK handle this automatically.

Related event: Anthropic Releases Claude Fable 5.2 and Mythos 5.2(29 posts)→

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