You are building a structured data extraction system using Claude. The system extracts information from unstructured documents, validates the output using JavaScript Object Notation (JSON) schemas, and maintains high accuracy. It must handle edge cases gracefully and integrate with downstream systems.

Your extraction system parses e-commerce product descriptions to extract specifications like dimensions, weight, and materials into JSON. Despite having a well-defined schema, the model inconsistently extracts the "materials" field – sometimes returning "cotton blend", other times "Cotton/Polyester mix", and occasionally omitting the field when material information is clearly present in the source.

What's the most effective way to improve extraction consistency?