> ## 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. # BYOK Whether the engine needs the caller's own key, saved in plugin settings: `required` (OpenRouter holds none), `optional` (OpenRouter's key is used unless the caller saved one), or `none` ## Example Usage ```typescript theme={null} import { BYOK } from "@openrouter/sdk/models"; let value: BYOK = "none"; // Open enum: unrecognized values are captured as Unrecognized ``` ## Values ```typescript theme={null} "required" | "optional" | "none" | Unrecognized ```