outlines

Generate type-safe JSON, XML, or code output using Pydantic models.

Updated Mar 13, 2026
One-click install
npx skills add https://github.com/hochoa13/Asistente-Harlest --skill outlines-hochoa13
Or copy as Structured Prompt for Agent
Please help me install this Agent Skill.
Skill: outlines
Source: https://github.com/hochoa13/Asistente-Harlest/tree/main/skills/mlops/inference/outlines
Command: npx skills add https://github.com/hochoa13/Asistente-Harlest --skill outlines-hochoa13

SYSTEM DOCUMENTATION & REQUIREMENTS

💡 This Skill requires outlines, transformers, vllm, pydantic, and includes scripts (resource) and references (resource) and assets (resource) components.

What problem does it solve?

This Skill guarantees valid JSON, XML, or code structure during generation, preventing LLM hallucinations and ensuring data integrity.

Core Features & Use Cases

  • Type-Safe Outputs: Use Pydantic models for robust, type-checked generation.
  • Local Model Support: Works with Transformers, vLLM, and llama.cpp for flexibility and privacy.
  • Maximized Inference Speed: Achieves zero-overhead structured generation.
  • Use Case: Automatically extract structured user profiles from free-form text into Pydantic objects, ensuring all fields (name, age, email) are correctly formatted and present.

Quick Start

Use the outlines skill to generate a JSON object representing a user with name, age, and email.

Frequently Asked Questions about outlines

High-intent search queries and answers about installing and using this skill.

FAQPage Schema
How do I guarantee valid JSON output from a local LLM?

To guarantee valid JSON output from a local LLM, you can use grammar-based constraints with Pydantic models. This enforces type-safe generation, preventing hallucinations and ensuring structural integrity during inference.

Can I use Pydantic models for structured text generation with vLLM?

Yes, you can use Pydantic models for structured text generation with vLLM. The framework supports local models like vLLM and Transformers, applying zero-overhead grammar constraints to maximize inference speed while ensuring type safety.

What's the best way to prevent LLM hallucinations in JSON generation?

The best way to prevent LLM hallucinations in JSON generation is applying grammar-based constraints. By mapping outputs directly to Pydantic models, the generation process is restricted to valid structures, ensuring data integrity and eliminating formatting errors.

Does structured generation work with Transformers and zero overhead?

Structured generation works with Transformers and zero overhead. The approach uses grammar-based constraints applied during the generation process, maximizing inference speed without adding latency to the local model's text generation pipeline.

How do I extract structured user profiles from free-form text into Pydantic objects?

To extract structured user profiles from free-form text into Pydantic objects, define a Pydantic model with the required fields like name, age, and email. The generation framework constrains the LLM to output valid, correctly formatted data matching your schema.

Why does my LLM output invalid JSON schema when generating text?

Your LLM outputs invalid JSON schema because standard generation lacks structural constraints. By implementing grammar-based constraints mapped to a JSON schema or Pydantic model, you force the LLM to generate only valid, type-safe JSON structures.