Claude Agent SDK
The agent harness behind Claude Code, as a library.
Build production agents with the same loop, tools, context management and permissions that power Claude Code.
- Vendor
- Anthropic
- Category
- Agent frameworks
- Pricing
- Open source
- Open source
- Yes
- License
- MIT
- Platforms
- Python, TypeScript
- Launched
- 2025
- Website
- docs.anthropic.com/en/docs/agent-sdk/overview
Features
- Built-in file & shell tools
- Subagents
- MCP
- Context compaction
Best for
- Agents
- Coding
Works with
- Claude Opus 5.5 — Anthropic. Anthropic’s flagship for demanding reasoning, coding and long-horizon agents.
- Claude Sonnet 5.5 — Anthropic. Near-flagship intelligence at a mid-tier price; the everyday workhorse for builders.
More agent frameworks
- Model Context Protocol — Anthropic (open standard). The open standard for connecting AI to tools and data.
- LangGraph — LangChain. Stateful, controllable agent orchestration.
- OpenAI Agents SDK — OpenAI. Lightweight multi-agent workflows with handoffs.
- CrewAI — CrewAI. Role-based multi-agent crews.
- Agent Development Kit — Google. Google’s open-source framework for multi-agent systems.
- Pydantic AI — Pydantic. Type-safe agent framework for Python.
- Microsoft Agent Framework — Microsoft. Successor to AutoGen and Semantic Kernel.
- Mastra — Mastra. The TypeScript agent framework.