core practice · implementation task
Schema-constrained extraction
Define a JSON schema and use structured-output mode to extract typed fields from unstructured text. Validate the result and reject on failure.
The mechanism
Free text is unparseable glue between systems. Structured outputs constrain generation to a schema (via grammar/JSON mode) so the model's answer is a typed object your code can trust — or reject.
Expected evidence
A validated typed object, or an explicit rejection.
Try this drill in the practice workspace →
Hints when you need them
- Use schema/JSON mode, not regex on prose.
- Always validate before trusting downstream.
Watch for these mistakes
- Parsing JSON out of prose with regex instead of schema mode
- No validation step, so malformed output crashes downstream
- Over-nesting schemas the model cannot reliably fill