LangGraph
LangGraph is an MIT-licensed framework from LangChain for building agents as graphs with state, with MCP support through an adapter we could not confirm in detail.
- Agent framework (code)
- Open source
- MCP
Free tier + paid · 44,183 stars
Agent framework (code)
Pydantic AI
Agent framework from Pydantic. Supports MCP servers.
Checked 2026-10-31
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Pydantic AI is an MIT-licensed Python agent framework from the team behind Pydantic. Its README describes a typed agent loop where any supported model is a string swap away, plus a Harness of capabilities for long-running work, an Evals package that grades final outputs and tool-call trajectories, and an optional connection to Pydantic Logfire for observability. It supports MCP servers. The library costs nothing; you pay for model calls, and Logfire is a separate product whose prices we did not check. We would suggest it to Python teams that already use Pydantic and want type checking and validated outputs from the start. The main limit is scope: it is a code library, so it suits developers rather than people wanting a canvas, and our comparison with other frameworks is the place to weigh it against LangGraph and CrewAI. Our read on 31 October 2026 covers the README and docs only, and we have not built with it ourselves.
Mentioned here
CrewAI
CrewAI is an MIT-licensed Python framework for teams of cooperating agents, with MCP support, plus a hosted product called AMP.
- Agent framework (code)
- Open source
- MCP
Free tier + paid · 60,313 stars
Agent Development Kit (ADK)
Agent Development Kit, or ADK, is Google's open-source, code-first framework for building, evaluating and deploying agents.
- Agent framework (code)
- Open source
- MCP
Free · 22,051 stars
OpenAI Agents SDK
The OpenAI Agents SDK is an MIT-licensed Python framework for multi-agent workflows, with a JavaScript and TypeScript version alongside.
- Agent framework (code)
- Open source
- MCP
Free · 30,399 stars
Claude Agent SDK
The Claude Agent SDK is Anthropic's library for building agents on the same loop that powers Claude Code.
- Agent framework (code)
- Open source
- MCP
Free · 8,394 stars
Mastra
Mastra is a TypeScript agent framework with MCP support.
- Agent framework (code)
- MCP
Free tier + paid · 29,218 stars
AI Agent Frameworks: Twelve Compared for Developers
Checked 2026-10-31
Agentic AI Frameworks: Patterns and Which Tool Fits
Checked 2026-10-31
Questions
How much does Pydantic AI cost?
Pricing: Free, checked 31 October 2026.
Is Pydantic AI open source?
Yes, under the MIT licence. The code is at github.com/pydantic/pydantic-ai.
Does Pydantic AI work with MCP servers?
Yes.
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Alternatives
AutoGen
AutoGen is Microsoft's framework for multi-agent applications, and its repository now carries an archived notice: Microsoft says it is not providing bug fixes, security fixes, new features or support, and tells new users to start with Microsoft Agent Framework, described as the production-ready successor with stable APIs.
- Agent framework (code)
- MCP
Free · 61,642 stars
