Models API Enhancement

The Claude Models API now includes model capability fields, enabling developers to programmatically discover what each model supports. The GET /v1/models and GET /v1/models/{model_id} endpoints now return:

• max_input_tokens: Maximum input token capacity
• max_tokens: Maximum total tokens supported
• capabilities object: Feature support details

This allows applications to dynamically adapt to model capabilities without hardcoding version-specific assumptions.

Extended Thinking Display Controls

A new display field for extended thinking lets developers control whether thinking content appears in API responses. Setting thinking.display: "omitted" returns thinking blocks with an empty thinking field while preserving the signature field for multi-turn conversation continuity.

Key benefits:

• Faster streaming by omitting verbose thinking content from responses
• Maintains conversation context across turns via signature preservation
• No billing changes—you pay the same regardless of display setting

Developers using extended thinking should review the Controlling thinking display documentation to optimize their implementations.