Structured outputs
Turn probabilistic model responses into fields a workflow can validate and use.
- 9 minutes
- intermediate
- Reviewed 2026-07-16
What is it?
Structured output constrains a model response to a schema with named fields and types. The result can be parsed, validated, and routed.
Why does it matter?
Free text is pleasant for reading but fragile for automation. A schema creates a clean boundary between interpretation and execution.
The mental model
The model proposes a structured object; software validates the contract before any action uses it.
A simple example
A ticket classifier returns category, priority, explanation, and needsHumanReview rather than an unstructured paragraph.
What it is not
A valid schema does not guarantee a correct decision. Semantic quality still needs evidence, thresholds, and evaluation.
Learn this first
These ideas make the lesson easier to place.
- JSON
- Schemas
- Model selection
Your first 60 minutes
Use one focused hour to make the idea concrete.
- Define a four-field schema.
- Test valid, missing, and unexpected inputs.
- Reject invalid output and add one retry with clearer instructions.
Build this first
Build a structured intake classifier that never sends an action unless validation succeeds.
When not to use it
Avoid elaborate schemas for purely conversational output that no system will consume.
What to learn next
Learn tool calling and human review.