Model : Model definition used for transforming usage into USD cost and/or tokenization. Models can have either simple flat pricing or tiered pricing: - Flat pricing: Single price per usage type (legacy, but still supported) - Tiered pricing: Multiple pricing tiers with conditional matching based on usage patterns The pricing tiers approach is recommended for models with usage-based pricing variations. When using tiered pricing, the flat price fields (inputPrice, outputPrice, prices) are populated from the default tier for backward compatibility.