Mid-conversation system messages now live on three more models

July 15, 2026Claude PlatformView original ↗

3 features

Mid-conversation system messages are now available on Claude Fable 5, Claude Mythos 5, and Claude Opus 4.8 on the Claude API, Claude in Amazon Bedrock, and Google Cloud. No beta header is required.

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Fetched July 18, 2026

Mid-conversation system messages now live on three more models

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