Claude Agent SDK

Rather than reimplementing an agent loop, developers can pull in the exact engine that powers Claude Code: Anthropic packages it as the Claude Agent SDK for Python and TypeScript, MIT licensed on GitHub. A simple async query interface streams messages from a running agent, while a client class holds bidirectional interactive sessions. Tools defined as plain decorated functions become in-process MCP servers with no separate process to manage, and these mix freely with external MCP servers. Hooks intercept the loop at points like PreToolUse for validation or policy enforcement, and permission controls pre-approve, block, or gate individual tools. Subagents, working directory control, and file tools such as Read, Write, Edit, and Bash carry over from Claude Code, whose CLI ships bundled with the package, so pip install claude-agent-sdk is the only setup beyond Python 3.10 or newer. The Python repository stands at about 8,000 stars, and the SDK has become the default route for teams building custom autonomous agents on Anthropic models, from CI bots to internal operations agents.