outlines

Generate schema-conforming JSON, XML, and code outputs with finite-state constraints.

Updated May 2, 2026
One-click install
npx skills add https://github.com/AlvaroBiano/hermes-agent --skill outlines-alvarobiano
Or copy as Structured Prompt for Agent
Please help me install this Agent Skill.
Skill: outlines
Source: https://github.com/AlvaroBiano/hermes-agent/tree/main/optional-skills/mlops/inference/outlines
Command: npx skills add https://github.com/AlvaroBiano/hermes-agent --skill outlines-alvarobiano

SYSTEM DOCUMENTATION & REQUIREMENTS

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

What problem does it solve?

Outlines enables deterministic generation of structured outputs that always conform to a defined schema or Pydantic model, reducing post-processing validation and errors.

Core Features & Use Cases

  • Constrained generation that enforces JSON/XML/code structure from schemas or Pydantic models
  • Native Pydantic integration for typed outputs and automatic validation
  • Local-model support (Transformers, llama.cpp, vLLM) with zero API dependencies
  • JSON schema compatibility and zero-overhead structured generation
  • Production-ready patterns for nested models, enums, and complex types

Quick Start

Describe the required output using a schema or model and let Outlines return a validated, typed result.

Frequently Asked Questions about outlines

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

FAQPage Schema
How do I generate structured JSON outputs that always conform to a Pydantic model?

You can generate structured JSON outputs by applying finite-state constraints during generation, which forces local models to produce text that always conforms to your Pydantic model and eliminates post-processing validation errors.

Does structured generation work with local models like vLLM and transformers?

Yes, structured generation works with local models like vLLM and transformers. It enforces schema-driven constraints natively, ensuring type-safe generation with zero API dependencies and robust error handling.

What is finite-state constrained generation for JSON schema compliance?

Finite-state constrained generation is a technique that pre-compiles validators from a JSON schema or Pydantic model, steering the model's token generation process to guarantee the output strictly matches the defined structure.

How do I enforce specific output formats like XML and code using local models?

You can enforce specific output formats like XML and code by defining the required structure through a schema or model, allowing the generation process to apply constraints that yield validated, typed results automatically.

Can I use Pydantic models for automatic validation of nested structures in LLM outputs?

Yes, you can use Pydantic models for automatic validation of nested structures, enums, and complex types. Native integration pre-compiles these models into validators to ensure type-safe, structured outputs.

Why do I need schema-driven generation instead of post-processing validation for local models?

Schema-driven generation is needed because it guarantees structural compliance during generation, dramatically reducing the post-processing validation overhead and runtime errors commonly associated with parsing unstructured local model outputs.