> ## 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. # CascadeMode How a universal `tool_search` query reaches the client's own tool search. Absent or `keywords`: a `select:` query becomes the words of the selected names and the limit is always filled. `native`: a `select:` query passes through verbatim when the client search documents `select:`, and the limit field is sent only when the model gave one, unless the client search requires it, in which case its documented default is sent. A tool the client sent with `defer_loading: true` that universal keeps direct is forwarded with that flag, so the provider loads it through the client search as it would without universal. Experimental. ## Example Usage ```python theme={null} from openrouter.components import CascadeMode # Open enum: unrecognized values are captured as UnrecognizedStr value: CascadeMode = "keywords" ``` ## Values This is an open enum. Unrecognized values will not fail type checks. * `"keywords"` * `"native"`