Commercial transition
Previous stateAnthropic's direct model catalogue did not include the Claude Sonnet 5.5 model identifier.
→New stateClaude Sonnet 5.5 is available from Anthropic under model identifier claude-sonnet-5-5.
Who is affected
Developers and organisations selecting Anthropic Claude models directly.
Action required
Evaluate the new model and update allowlists, routing and evaluation baselines where adoption is appropriate.
Evidence boundary
This record covers direct provider model availability only. It does not collapse API unit pricing, third-party plan entitlement, marketplace terms or negotiated enterprise terms into the availability event.
Timeline
- Claude Sonnet 5.5 released
Anthropic published the model and direct model identifier.
Official sources
- Claude Sonnet 5.5Anthropic · 2026-09-28 · Official Anthropic model-availability authority