Documentation

Model cards

Claude Opus 4.5 System Card

Detailed documentation of Claude Opus 4.5.

Claude Haiku 4.5 System Card

Detailed documentation of Claude Haiku 4.5.

Claude Sonnet 4.5 System Card

Detailed documentation of Claude Sonnet 4.5.

Claude Opus 4.1 System Card

Detailed documentation of Claude Opus 4.1.

Claude 4 System Card

Detailed documentation of Claude 4 models.

Claude Sonnet 3.7 System Card

System card for Claude Sonnet 3.7 with performance and safety details.

Claude 3 Model Card

Detailed documentation of Claude 3 models including latest 3.5 addendum.

Learning resources

Quickstarts

Deployable applications built with our API.

Courses

Step by step lessons on building with Claude.

Cookbook

Replicable code samples and implementations.

Prompt library

Explore optimized prompts for a breadth of business and personal tasks.

Use case guides

In-depth production guides for building common use cases with Claude.

Glossary

Key terms and concepts for working with Claude and language models.

Resources for AI ingestion

API primer for Claude ingestion

Concise API guide meant for ingestion by Claude.

Claude API Docs Overview

Concise overview of Claude API documentation, optimized for LLM ingestion.

llms.txt

LLM-optimized documentation index.

llms-full.txt

Complete LLM-optimized documentation.