Best AI Agent Frameworks (2026)
Frameworks, SDKs and harnesses developers use to build their own AI agents. Below are the top 20 of 86 matching tools in the AgentScout directory, ranked.
How we ranked: Ranked by GitHub stars as recorded on each AgentScout listing (link checks 2026-10-18). Tools without a tracked public repo come after, in alphabetical order. Stars measure developer popularity, not quality or fit for your job, so read each listing before you choose. No paid placements.
1. Hermes Agent (Nous Research)
Open-source agent harness; v0.21.7 stable shipped Oct 12, v0.22.0 RCs Oct 13-14.
Pricing (as stated): Open source · Active, frequent releases
2. DeepSeek Harness
DeepSeek's open-source agent harness with a local web UI, built so that every tool, model and scheduled task is a swappable plugin; still a developer preview.
Pricing (as stated): Open source · Mature
3. AutoGPT
One of the first autonomous agent projects, now a platform for building, deploying and running continuous AI agents that automate workflows.
Pricing (as stated): Open source + cloud · Mature
4. RAGFlow
Open-source RAG engine with deep document parsing and agent features for building grounded question-answering over your files.
Pricing (as stated): Open source + cloud · Mature
5. Ruflo
Open-source multi-agent meta-harness for Claude Code, Codex, and MCP clients; Oct 13 release adds Mods (mission workflows) and a single control plane with human approval.
Pricing (as stated): Open source (MIT); model costs still apply · Active
6. MetaGPT
Multi-agent framework that assigns roles like product manager and engineer to LLM agents to build software.
Pricing (as stated): Open source · Mature
7. AutoGen
Microsoft's framework for multi-agent conversations.
Pricing (as stated): Open source · Mature
8. CrewAI
Framework for role-based multi-agent crews.
Pricing (as stated): Open source + paid cloud · Mature
9. LlamaIndex
Framework for agents over your data (RAG, document agents).
Pricing (as stated): Open source + paid cloud · Mature
10. LangGraph
Framework for stateful, graph-based agent workflows.
Pricing (as stated): Open source · Mature
11. Agno
Python framework and runtime for building, running and managing multi-agent systems with memory, knowledge and tools.
Pricing (as stated): Open source + cloud · Mature
12. OpenHuman
Lightweight open-source agent harness designed to run many agents cheaply on small servers.
Pricing (as stated): Open source · Mature
13. PageIndex
Document index for reasoning-based, vectorless RAG that lets agents navigate long documents like a table of contents.
Pricing (as stated): Open source + cloud · Mature
14. CopilotKit
Frontend stack for putting agents and generative UI into React and other apps, from the makers of the AG-UI protocol.
Pricing (as stated): Open source + cloud · Mature
15. AgentScope
Framework for building and running transparent multi-agent applications with visual debugging.
Pricing (as stated): Open source · Mature
16. Orkes
Orchestration platform built on Conductor for durable workflows and AI agents.
Pricing (as stated): Open source + cloud · Mature
17. LangChain Deep Agents
Library for long-running agents with subagents and skills; 0.7.23 (Oct 7) adds pinned_skills.
Pricing (as stated): Open source · Active
18. OpenAI Agents SDK (Python)
OpenAI's Python SDK for building multi-agent workflows; v0.23.0/0.23.1 released Oct 1-2.
Pricing (as stated): Open source · Mature, official SDK
19. smolagents
Hugging Face's minimal library for code-writing agents.
Pricing (as stated): Open source · Active
20. Haystack
Open-source orchestration framework for building production LLM apps, RAG and agents.
Pricing (as stated): Open source + cloud · Mature
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Related: AI agents for building AI agents · Multi-agent systems
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Facts come from our directory listings; pricing is as each maker states it and GitHub stars are as recorded on each listing. Check official sites before you choose.