outlines

Generate structured JSON, Pydantic, and regex outputs from local models.

Updated Apr 27, 2026
One-click install
npx skills add https://github.com/x-TheFox/Corvus --skill outlines-x-thefox
Or copy as Structured Prompt for Agent
Please help me install this Agent Skill.
Skill: outlines
Source: https://github.com/x-TheFox/Corvus/tree/main/skills/mlops/inference/outlines
Command: npx skills add https://github.com/x-TheFox/Corvus --skill outlines-x-thefox

SYSTEM DOCUMENTATION & REQUIREMENTS

What problem does it solve?

Outlines provides a disciplined approach to generating structured outputs (JSON, Pydantic, and regular-expression constrained text) from LLM prompts, ensuring outputs conform to schemas and are easier to validate.

Core Features & Use Cases

  • Constrained token sampling via grammar-based generation (CFG/FSM) to guarantee valid outputs.
  • Structured generators for JSON, Pydantic, and regex outputs, with backends that support local models (Transformers, llama.cpp, vLLM).
  • Pydantic integration and automatic schema translation for type-safe results; practical use cases include data extraction, form processing, and multi-entity extraction.
  • Backed by a flexible architecture enabling production-grade workflows and zero-overhead validation.

Quick Start

Load a local model with outlines and generate a typed JSON output from a prompt describing the data you need.

Frequently Asked Questions about outlines

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

FAQPage Schema
How do I generate JSON that strictly conforms to a Pydantic schema using local models?

Enforcing FSM grammar constraints during token sampling guarantees structured JSON generation that strictly conforms to Pydantic schemas using local models. Outlines integrates Pydantic for automatic schema translation, delivering type-safe results with zero runtime overhead.

What is grammar-based generation and how does it guarantee valid LLM outputs?

Grammar-based generation enforces constrained token sampling via finite state machine (FSM) or context-free grammar (CFG) rules. This mechanism guarantees valid LLM outputs by ensuring generated text always conforms to specified JSON, Pydantic, or regex schemas.

Can I use regex constraints for text classification tasks with vLLM or llama.cpp backends?

Regex constraints are supported for text classification tasks across multiple local model backends including vLLM and llama.cpp. Outlines applies regex constraints during generation to ensure outputs match specific patterns required by classification workflows.

Does structured generation with local models add inference overhead?

Structured generation with local models operates with zero overhead by applying FSM constraints directly during token sampling. Outlines enforces schema conformity during the generation process itself, eliminating the need for post-hoc validation or retry loops.

What's the best way to extract multiple entities from unstructured text into typed JSON?

Extracting multiple entities into typed JSON is best handled by combining Pydantic schemas with FSM grammar constraints during local model generation. Outlines supports multi-entity extraction workflows by guaranteeing outputs conform to strict schemas for data extraction and form processing.