Claude Sonnet 5.5

Anthropic · · 6 days after Claude Opus 5.5

Partially verified

0 of 2 published values traced to a source2 primary sources, 0 archived2 not researched yet

Why this status

Newly added. Sources are not archived and no value has been traced to one yet — run `npm run enrich`.

What these states mean · How records are judged · Has this record changed?

Anthropic launched Claude Sonnet 5.5 (claude-sonnet-5-5) on the Claude API, Amazon Bedrock, Claude Platform on AWS, Google Cloud and Microsoft Foundry. Anthropic's models table gives it a 1M-token context window, 128K maximum output, adaptive thinking, and pricing of $2 / $10 per million input / output tokens.

reasoninglong-context

Details

ReleasedSeptember 28, 2026
CompanyAnthropic
FamilyClaude
Lineageafter Claude Sonnet 5
EraAgentic systems
TypeLanguage model · LLM
ModalitiesNot recorded
CapabilitiesReasoning
WeightsProprietary
LicenceNot applicable — proprietary
Context window1M tokens
ParametersNot researched

Current information, elsewhere

This record is a historical one: every figure above is traced to a dated primary source. For what is true today — live pricing, current rankings, availability — these are better maintained than anything here could be.

Sources

Record status: partly verified · confidence 60/100 · 2 of 2 primary

Newly added. Sources are not archived and no value has been traced to one yet — run `npm run enrich`.

Primary means published by the organisation that made the model. Verified records require at least one.

Claude family

  1. Claude 1 March 14, 2023
  2. Claude 2 July 11, 2023
  3. Claude 3 Opus March 4, 2024
  4. Claude 3.5 Sonnet June 21, 2024
  5. Claude 3.7 Sonnet February 24, 2025
  6. Claude Opus 4 May 22, 2025
  7. Claude Sonnet 4.5 September 29, 2025
  8. Claude Haiku 4.5 October 15, 2025
  9. Claude Opus 4.5 November 24, 2025
  10. Claude Opus 4.6 February 5, 2026
  11. Claude Sonnet 4.6 February 17, 2026
  12. Claude Opus 4.7 April 16, 2026
  13. Claude Opus 4.8 May 28, 2026
  14. Claude Fable 5 June 9, 2026
  15. Claude Mythos 5 June 9, 2026
  16. Claude Sonnet 5 June 30, 2026
  17. Claude Opus 5 July 24, 2026
  18. Claude Fable 5.1 September 1, 2026
  19. Claude Mythos 5.1 September 1, 2026
  20. Claude Opus 5.5 September 22, 2026
  21. Claude Sonnet 5.5 September 28, 2026
  22. Claude Haiku 5.5 October 7, 2026

What changed from Claude Sonnet 5

Compared with the previous release in this series. A field appears only when both records state a value — where one does not, it is listed as uncomparable rather than dropped, because a gap in our research is not a finding about the model.

Not comparable: Parameters (not researched on both releases); Capabilities and modalities (not researched on both releases)

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