Use Gemini structured output and keep missing data explicit
Select a supported output schema, represent unknown values deliberately and validate the completed response before importing it.
In brief
Gemini structured output constrains the response format for supported models. It is useful for consistent fields, but a conforming object can still contain an incorrect extraction or unsupported fact.
An explicit unknown state prevents an unreadable field becoming a fabricated value or a misleading zero.
Choose fields for the decision
For a document extract, include only the name, date or number needed and the evidence reference if appropriate. Define how an unknown or unreadable value appears. Avoid unnecessary personal fields simply because a schema can request them.
Use Gemini’s actual configuration
Read the current structured-output guide for the SDK and endpoint in use. A response setting from another provider is not automatically equivalent. Handle an invalid-schema error visibly instead of silently falling back to unconstrained prose that your importer still treats as structured data.
Validate meaning and completion
Check refusal, interruption and schema parsing first. Then reconcile dates, units and totals with the source. Keep uncertain entries for review rather than forcing them through an import, and do not present a generated example as a successful live API test.
Before you act
Gemini supports a defined schema subset and model-specific combinations. Check the current API route rather than assuming every JSON Schema property or tool combination works.
What to do next
- Define required fields, types and an allowed missing-data representation.
- Configure the supported structured-output mechanism for the selected model.
- Check completion, parse and validate the values against the source before storing them.
