When a field comes back empty (null), it usually means one of the following:
The data genuinely does not exist in that document — for example, not every invoice has a VAT number
The field name or example does not match how the data is labelled in the document
The data appears in a format that Lymnus did not recognise as matching your field type
To fix this, try:
Reviewing the document manually to confirm the data is actually there
Updating the field's example value to match the exact format used in your documents
Adding a description or constraint to give the AI more context about what to look for
Splitting complex fields into simpler ones — for example, extract "first_name" and "last_name" separately instead of "full_name"