What is Structured Outputs — Force LLMs to Return Valid JSON?

Complete guide to getting reliable structured JSON from LLMs. Covers OpenAI structured outputs, Claude tool use, Instructor library, and Outlines for guaranteed valid responses.

Is Structured Outputs — Force LLMs to Return Valid JSON free to use?

Yes. Structured Outputs — Force LLMs to Return Valid JSON is freely available on TokRepo. Check the Source & Thanks section on the asset page for the specific open-source license.

How do I install Structured Outputs — Force LLMs to Return Valid JSON?

Visit the asset page on TokRepo and click "Copy for agent" to get the installation instructions. Most assets can be installed with a single command.

Structured Outputs — Force LLMs to Return Valid JSON

What Are Structured Outputs?

Force an LLM to return a specific format (JSON/typed object) rather than free text. The key to building reliable AI pipelines.

TL;DR: Force LLMs to return valid JSON. OpenAI uses response_format, Claude uses tool_choice, Instructor wraps multiple providers, Outlines open-source guided generation.

Method Comparison

1. OpenAI Structured Outputs — Server-side schema enforcement

2. Claude Tool Use — Schema enforcement via tool calls

3. Instructor — Multi-provider wrapper with retries

4. Outlines — Token-level guided generation for open-source models

Best Practices

Keep schemas simple
Add field descriptions
Provide few-shot examples
Validate business logic