Differences in thinking across model versions - Amazon Bedrock
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Differences in thinking across model versions

The Messages API handles thinking differently across Claude 3.7 Sonnet and Claude 4 models, primarily in redaction and summarization behavior. The following table summarizes those differences.

Feature

Claude 3.7 Sonnet

Claude 4 Models

Thinking output

Returns the full thinking output

Returns summarized thinking

Redaction handling

Uses redacted_thinking blocks

Redacts and encrypts full thinking, returned in a signature field

Interleaved thinking

Not supported

Supported with a beta header