> ## 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. # MessagesMessageParamContentUnion5 ## Supported Types ### ```go theme={null} messagesMessageParamContentUnion5 := components.CreateMessagesMessageParamContentUnion5Str(string{/* values here */}) ``` ### ```go theme={null} messagesMessageParamContentUnion5 := components.CreateMessagesMessageParamContentUnion5ArrayOfMessagesMessageParamContentUnion4([]components.MessagesMessageParamContentUnion4{/* values here */}) ``` ## Union Discrimination Use the `Type` field to determine which variant is active, then access the corresponding field: ```go theme={null} switch messagesMessageParamContentUnion5.Type { case components.MessagesMessageParamContentUnion5TypeStr: // messagesMessageParamContentUnion5.Str is populated case components.MessagesMessageParamContentUnion5TypeArrayOfMessagesMessageParamContentUnion4: // messagesMessageParamContentUnion5.ArrayOfMessagesMessageParamContentUnion4 is populated } ```