Best Python frameworks for building AI agents
Code-first frameworks for Python developers who want control over agent loops, tools, handoffs and state. All of these ship a Python SDK.
Ranked by score on our 100-point rubric (how we score). Scores are initial editorial estimates from public information, not hands-on tests. Pricing is labeled verified (checked on the vendor's official pricing page, with date) or unverified.
Quick picks
| # | Tool | Tier | Score |
|---|---|---|---|
| 1 | LangGraph Stateful graph-based agent orchestration | A | 80 |
| 2 | OpenAI Agents SDK Lightweight framework for multi-agent apps | A | 77 |
| 3 | Claude Agent SDK Build agents on the Claude Code harness | A | 76 |
| 4 | CrewAI Role-based multi-agent framework | A | 76 |
| 5 | Pydantic AI Type-safe Python agent framework | A | 74 |
The ranking
-
LangChain's low-level framework for building controllable, long-running multi-agent workflows.
- Best for
- You need production agents with explicit control flow and persistence.
- Skip it if
- You want a no-code tool or a quick script.
- Pricing
- LangSmith Developer $0/seat; Plus $39/seat/mo then pay-as-you-go ✓ verified on the official pricing page, Oct 18, 2026
- Platforms
- API · Python SDK · JS SDK
-
Open-source SDK with agents, handoffs, guardrails and tracing; works with many model providers.
- Best for
- You want a minimal, well-documented agent SDK.
- Skip it if
- You need a visual builder.
- Pricing
- Free and open source; pay for model usage unverified editorial summary, not yet confirmed on an official pricing page
- Platforms
- Python SDK · JS SDK
-
Anthropic's SDK exposing the Claude Code agent loop, tools, and context management for custom agents.
- Best for
- You want Claude Code's proven agent loop inside your own product.
- Skip it if
- You need to use non-Claude models.
- Pricing
- Free SDK; pay for Claude API usage unverified editorial summary, not yet confirmed on an official pricing page
- Platforms
- Python SDK · TypeScript SDK
-
Python framework and platform for crews of role-playing agents that collaborate on tasks.
- Best for
- You want multi-agent teams with minimal boilerplate.
- Skip it if
- You need fine-grained deterministic control.
- Pricing
- Open-source framework free; hosted platform paid unverified editorial summary, not yet confirmed on an official pricing page
- Platforms
- Python SDK · web
-
Agent framework from the Pydantic team focused on typed outputs, dependency injection and observability.
- Best for
- You want type-safe, production-style Python agents.
- Skip it if
- You want built-in multi-agent role play.
- Pricing
- Framework is open source; Logfire Personal free; Team $49/mo ✓ verified on the official pricing page, Oct 18, 2026
- Platforms
- Python SDK
Head-to-head comparisons
- LangGraph vs OpenAI Agents SDK
- Claude Agent SDK vs LangGraph
- CrewAI vs LangGraph
- Claude Agent SDK vs OpenAI Agents SDK
- CrewAI vs OpenAI Agents SDK
- Claude Agent SDK vs CrewAI
FAQ
What is the best AI tool for building agents in Python?
LangGraph ranks first with 80/100 (A-tier). Stateful graph-based agent orchestration. Use it when you need production agents with explicit control flow and persistence. Next in our ranking: OpenAI Agents SDK (77/100, A-tier) and Claude Agent SDK (76/100, A-tier).
Which AI tools for building agents in Python have a free tier?
In our pricing data, LangGraph (verified), OpenAI Agents SDK (unverified), Claude Agent SDK (unverified), CrewAI (unverified) and Pydantic AI (verified) list a free tier. "Unverified" means it is an editorial summary we have not yet confirmed on the vendor's official pricing page, so check the vendor before relying on it.
Are there open-source options for building agents in Python?
Yes. LangGraph, OpenAI Agents SDK, Claude Agent SDK, CrewAI and Pydantic AI are listed as open source or open weights. Check each project's license before commercial use.
How are these tools ranked?
Each tool is scored out of 100 on our public rubric: job fit (30), ease (15), value (15), momentum (15), openness and portability (10), trust and maturity (10) and a builder/gamer bonus (5). S-tier is 85+, A-tier 70–84, B-tier 55–69 and C-tier below 55. Current scores are initial editorial estimates from public information, not hands-on tests, and sponsors can't buy points.