> ## Documentation Index > Fetch the complete documentation index at: https://openrouter.ai/docs/llms.txt > Use this file to discover all available pages before exploring further. # ReasoningMode Selects the reasoning mode. `standard` is the default; `pro` engages deeper reasoning on models that support it, billed at standard token rates. Only supported by OpenAI GPT-5.6 and newer. ## Example Usage ```go theme={null} import ( "github.com/OpenRouterTeam/go-sdk/models/components" ) value := components.ReasoningModeStandard // Open enum: custom values can be created with a direct type cast custom := components.ReasoningMode("custom_value") ``` ## Values | Name | Value | | ----------------------- | -------- | | `ReasoningModeStandard` | standard | | `ReasoningModePro` | pro |