What does the 'anthropic-beta' header enable in Claude API requests?
Select an answer to reveal the explanation.
Short Explanation and Infographic
The anthropic-beta header unlocks specific API features that are in preview — like extended thinking or other experimental capabilities — before they graduate to the stable API.
Full explanation below image
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 (e.g., '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. Option A confuses beta features with beta model versions — they're separate. Option C invents a false pricing incentive. Option D invents a false rate limit bypass.