Defined term
Structured output
Constraining model output to a strict schema (JSON, regex, grammar) for reliable downstream parsing.
Structured output forces the model to produce responses matching a declared schema. Modern APIs support JSON mode, JSON schema, and grammar-constrained decoding. Structured output is the difference between a demo and a production pipeline: it makes outputs parseable, validatable, and storable in databases without retry logic.
When it matters
When downstream code parses model output. Replacing 'write a JSON' prompts with enforced schemas eliminates the entire class of malformed-output bugs.
Real example
An extraction agent returning {invoice_number, vendor_name, total_amount, line_items[]} with JSON schema enforcement. Downstream accounting system receives 100% schema-valid payloads; previously had a 4% malformed rate causing manual fixes.
KPIs to watch
Schema validation rate (>99.5% with enforcement, vs ~96% without), downstream parse errors (target: 0), average prompt token cost (lower with structured vs prose).
Related terms
Function calling
Specific implementation of tool use where the model emits structured JSON calls to registered functions.
Agentic AI
AI systems that can plan, take multi-step actions, and use tools to complete tasks autonomously.
Autonomous agent
An AI agent that completes a defined task without per-step human input.
RAG (Retrieval-Augmented Generation)
Generation grounded in retrieved source documents rather than the model's parametric memory alone.
See it in action
We use this every week
Book a 30-min call and we'll walk you through how Structured output shows up in a real engagement we're running.
Book a 30-min call