When specifying default values in schemas or configurations, ensure they match the declared type to prevent validation errors and unpredictable behavior. For object types, use empty objects (`{}`) not null, undefined, or arrays. For string types that should be empty by default, use empty strings (`""`) not null. This practice improves type safety and prevents runtime type errors. ```diff // INCORRECT: Type mismatch between declared type and default { "type": "object", "description": "Document data as JSON object.", "default": [], // An array default for an object type } // CORRECT: Type-consistent defaults { "type": "object", "description": "Document data as JSON object.", "default": {}, // An object default for an object type } // CORRECT: Empty string default for optional string { "type": "string", "description": "Optional document ID", "default": "", // Empty string instead of null } ```