outlines

Constrain generation with Pydantic types and JSON schema validation.

Updated Mar 30, 2026
One-click install
npx skills add https://github.com/attentiondotnet/hermes-agent --skill outlines-attentiondotnet
Or copy as Structured Prompt for Agent▼
Please help me install this Agent Skill.
Skill: outlines
Source: https://github.com/attentiondotnet/hermes-agent/tree/main/skills/mlops/inference/outlines
Command: npx skills add https://github.com/attentiondotnet/hermes-agent --skill outlines-attentiondotnet

SYSTEM DOCUMENTATION & REQUIREMENTS

What problem does it solve?

Outlines enables guaranteed structurally valid outputs (JSON/XML/code) by constraining generation with Pydantic-based types and by leveraging grammar-driven constraints, so downstream systems always get predictable data.

Core Features & Use Cases

  • Type-safe outputs: use Pydantic models or JSON schemas to validate and coerce results.
  • Local-model support: run with transformers, vLLM, or llama.cpp for zero-overhead generation.
  • Structured generation at speed: deterministic generation with FSM-based constraints to maximize throughput and reliability.
  • Use Case: Build production-grade data extraction pipelines that always return validated data structures.

Quick Start

Prompt the AI to generate a validated JSON output by supplying a Pydantic model and a sample schema.

Frequently Asked Questions about outlines

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

FAQPage Schema
How do I ensure local models generate valid JSON output?▼

Ensure local models generate valid JSON by constraining generation with Pydantic-based types and grammar-driven constraints. This guarantees structurally valid outputs, providing predictable data for downstream systems without runtime parsing errors.

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

Yes, you can use Pydantic models for structured generation with vLLM. The framework supports local backends like vLLM, transformers, and llama.cpp, enabling zero-overhead structured generation with type-safe outputs.

What is the best way to validate LLM outputs against a JSON schema locally?▼

The best way to validate LLM outputs against a JSON schema locally is applying grammar-based constraints. This enforces deterministic generation via FSM logic, ensuring outputs structurally match your schema before parsing.

Does grammar-based structured generation slow down local model inference?▼

Grammar-based structured generation does not slow down local model inference. It uses FSM-based constraints to maximize throughput and reliability, providing deterministic generation with zero overhead during text generation.

How do I build a production data extraction pipeline with guaranteed structured outputs?▼

Build a production data extraction pipeline by supplying a Pydantic model and sample schema to the AI prompt. This constrains generation to validate and coerce results, ensuring downstream systems always receive predictable data structures.