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AnthropicClaude API
The Messages API response now includes usage.output_tokens_details.thinking_tokens, reporting how many of…
AI summary
Written by AI from the official notes. Check them for exact details.The Messages API now reports thinking tokens in the response.
- New field for thinking tokens in API response
- Breakdown appears on final message_delta event
- No beta header needed for this feature
Why it matters: Developers using the Messages API should care for accurate billing and token usage tracking.
Full release notes
- The Messages API response now includes
usage.output_tokens_details.thinking_tokens, reporting how many of the billed output tokens were extended thinking. When streaming, the breakdown appears only on the finalmessage_deltaevent. No beta header is required.