What does the 'anthropic-beta' header enable in Claude API requests?
Select an answer to reveal the explanation.
Short Explanation
The anthropic-beta header lets you opt into experimental API features that are still in beta testing and not yet part of the stable API. You use it to try things like extended thinking before they become standard.
Full Explanation
The 'anthropic-beta' header is a mechanism for accessing API features that are in beta testing. Developers opt into specific beta features by including the relevant feature flag value in this header, for example 'anthropic-beta: extended-thinking-2025-01-01'. Beta features may change without notice, have different behavior, or be discontinued. This allows Anthropic to test new capabilities with early adopters before stabilizing the API contract. The option about accessing beta versions of Claude models not yet publicly available confuses beta features with beta model versions, which are separate. The option about reduced pricing as a beta tester reward invents a false pricing incentive. The option about bypassing rate limits during beta testing periods invents a false rate limit bypass.