CLI, SDKs, and libraries

Official tools for building with the Claude API: the ant CLI, client SDKs in seven languages, and framework-specific libraries.

Anthropic provides three kinds of official tooling for building with the Claude API:

CLI: The ant command-line tool for shell scripting and interactive use.
Client SDKs: General-purpose Messages API clients for Python, TypeScript, C#, Go, Java, PHP, and Ruby. Each SDK provides idiomatic interfaces, type safety, and built-in support for streaming, retries, and error handling.
Libraries and integrations: Packages and compatibility layers that expose Claude inside another framework's API surface rather than the Messages API directly.

CLI

ant CLI

Shell scripting, typed flags, response transforms

Client SDKs

Python

Sync and async clients, Pydantic models

TypeScript

Node.js, Deno, Bun, and browser support

.NET Standard 2.0+, IChatClient integration

Context-based cancellation, functional options

Java

Builder pattern, CompletableFuture async

PHP

Value objects, builder pattern

Ruby

Sorbet types, streaming helpers

Libraries and integrations

Libraries and integrations expose Claude through another framework's API surface. They are not general-purpose Messages API clients.

Apple Foundation Models

Swift package for Apple's LanguageModelSession API

OpenAI SDK compatibility

Use Claude through the OpenAI SDK surface

Building agents or using Claude Code?

The CLI, client SDKs, and libraries are for calling the Claude API yourself: you send each request and handle each response. Claude Code, the Claude Agent SDK, and Claude Managed Agents work at a higher level, providing the agent loop, tool execution, and runtime.

Claude Code

Agentic coding tool for delegating coding tasks to Claude

Claude Agent SDK

Build agents that run in a process you operate

Claude Managed Agents

Run agents in Anthropic's managed infrastructure

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CLI, SDKs, and libraries

Official tools for building with the Claude API: the ant CLI, client SDKs in seven languages, and framework-specific libraries.

Anthropic provides three kinds of official tooling for building with the Claude API:

CLI: The ant command-line tool for shell scripting and interactive use.
Client SDKs: General-purpose Messages API clients for Python, TypeScript, C#, Go, Java, PHP, and Ruby. Each SDK provides idiomatic interfaces, type safety, and built-in support for streaming, retries, and error handling.
Libraries and integrations: Packages and compatibility layers that expose Claude inside another framework's API surface rather than the Messages API directly.