PluginStackPydantic AI
Pydantic AI official site ↗Last checked against the official docs:
What it does
A typed Python agent framework from the Pydantic team. You define agents with typed outputs and tools, and switching model providers is a one-string change. Companion packages add a harness for long-running agents (files, shell, sub-agents) and Pydantic Evals for testing. MIT licensed.
Who it's for
Python developers who like type hints and want validated, structured outputs from their agents.
How to set it up
Needs Python 3.11 or newer. Install:
bashuv add pydantic-aiFor a ready-made coding agent toolkit, add the harness too:
bashuv add pydantic-ai pydantic-ai-harnessSet your provider's API key (for example OPENAI_API_KEY or ANTHROPIC_API_KEY) and follow the docs at pydantic.dev/docs/ai.
Check the official Pydantic AI docs for the latest steps.
Example prompts
Build a Pydantic AI agent that extracts invoice data into a typed Invoice model.Add a tool to this agent that looks up a customer by email in our database.Write Pydantic Evals tests for this agent's outputs.Demo
Demo coming soon
A short walkthrough of Pydantic AI in action.
More Agent Frameworks
- Vercel
AI SDK
Vercel's provider-agnostic TypeScript toolkit for building AI apps and agents. It works with Next.js, React, Svelte, Vue, Angular and Node.js, and its UI hooks cover React, Svelte and Vue. One API covers OpenAI, Anthropic, Google and many more providers, either through Vercel AI Gateway (the default) or each provider's own package. Apache-2.0.
- CrewAI
CrewAI
A Python framework for multi-agent automation. Crews are teams of role-based agents that work together on a task; Flows are event-driven workflows with state and branching that can call crews. The CLI scaffolds projects, which are JSON-first by default. MIT licensed.
- LangChain
LangGraph
A low-level framework for building long-running, stateful agents as graphs. It provides durable execution (agents resume after failures), human-in-the-loop interrupts and short- and long-term memory. It works on its own or with LangChain and LangSmith. A JS version (LangGraph.js) is also available. MIT licensed.
- Mastra
Mastra
A TypeScript framework for AI apps and agents. It includes model routing across 40+ providers, agents with tools, graph-based workflows with suspend/resume, memory and RAG, MCP server authoring, evals and observability, plus a local Studio UI. Apache-2.0, except code in ee/ folders, which uses an enterprise license.
- OpenAI
OpenAI Agents SDK
A lightweight Python framework for building agents and multi-agent workflows. It covers agents with tools and handoffs, guardrails, human-in-the-loop, sessions, tracing, sandbox agents and voice/realtime agents. It works with OpenAI's APIs and, per the README, 100+ other LLMs. A JS/TS version exists too. MIT licensed.