Claude Sonnet 4.6

The Sonnet 4.6 reference documents this exact version as a legacy model. Keep its full identifier in an experiment: a tool's short “Sonnet” label does not establish which version answered. Check the provider's lifecycle notice before depending on the version for future work.

Our API pricing worksheet uses a dated Sonnet 4.6 example. Reuse the calculation method with the rates and conditions shown for your route today. Separate cache reads from writes and misses; token savings require an observed cache hit. Count retries and accepted results rather than comparing only the price of one successful call.

For a migration trial, keep several examples that matter to your application: correct JSON, a tool invocation and an answer grounded in a supplied document. Compare the same examples before changing traffic. If the workload runs through Claude Code, use the Claude Code guide to identify whether you are spending subscription capacity or an API budget.