Best Open-Source MCP Servers (2026)
Open-source MCP servers and MCP infrastructure you can run yourself and connect to Claude Code, Cursor, Codex and other MCP clients. Below are the top 25 of 120 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. REA
MCP server and CLI that lets coding agents reverse engineer native binaries, Electron and JavaScript apps, .NET assemblies and live websites, using Ghidra, Hopper or IDA under the hood.
Pricing (as stated): Open source · Mature
2. MCP reference servers
Official collection of reference MCP servers.
Pricing (as stated): Open source · Mature
3. Mem0
Memory layer for AI agents.
Pricing (as stated): Open source + paid cloud · Mature
4. Hindsight
Agent memory system that stores experiences and learns from them so agents improve over time.
Pricing (as stated): Open source + cloud · Mature
5. LocalAI
Self-hosted engine with an OpenAI-compatible API for running LLM, vision, voice and image models on your own hardware, including agents.
Pricing (as stated): Open source · Mature
6. Codebase Memory MCP
MCP server that indexes codebases into a persistent knowledge graph so coding agents can look up structure quickly.
Pricing (as stated): Open source · Mature
7. GitHub MCP Server
GitHub's official MCP server for letting agents work with repositories, issues, pull requests and Actions.
Pricing (as stated): Open source · Mature
8. Cognee
Open-source memory platform that builds knowledge graphs so agents keep long-term memory.
Pricing (as stated): Open source + cloud · Mature
9. Graphiti
Builds real-time, temporal knowledge graphs that serve as memory for AI agents.
Pricing (as stated): Open source · Mature
10. Google Workspace CLI
Official Google Workspace command-line tool for Drive, Gmail, Calendar, Docs and more, usable by agents.
Pricing (as stated): Open source · Mature
11. Serena
MCP toolkit that gives coding agents semantic code retrieval and editing, like IDE features.
Pricing (as stated): Open source · Mature
12. Chroma
Open-source search and vector database widely used for agent memory and RAG.
Pricing (as stated): Open source + cloud · Mature
13. TencentDB-Agent-Memory
Team-level memory hub that turns conversations, docs and code into shared memory for agents.
Pricing (as stated): Open source · Mature
14. FastMCP
Pythonic framework for building MCP servers and clients quickly.
Pricing (as stated): Open source · Mature
15. MCP Python SDK
Official Python SDK for building Model Context Protocol servers and clients.
Pricing (as stated): Open source · Mature
16. n8n-MCP
MCP server that lets Claude, Cursor and other agents build n8n workflows for you.
Pricing (as stated): Open source · Mature
17. MCP Toolbox for Databases
Open-source MCP server from Google for connecting agents to databases.
Pricing (as stated): Open source · Mature
18. NVIDIA OpenShell
Sandboxed runtime for autonomous agents with declarative YAML policies on file, network and credential access.
Pricing (as stated): Open source (Apache 2.0) · Active; part of newly announced Open Agent Safety Platform
19. OpenSandbox
Secure, fast sandbox runtime for AI agents to run code.
Pricing (as stated): Open source · Mature
20. Corsair
Integration layer for connecting your users' apps to agents.
Pricing (as stated): Open source · Mature
21. Casdoor
Agent-first identity and access management with an MCP and agent gateway.
Pricing (as stated): Open source · Mature
22. MCP TypeScript SDK
Official TypeScript SDK for building MCP servers and clients.
Pricing (as stated): Open source · Mature
23. EverOS
Local-first, portable memory layer for AI agents stored as Markdown.
Pricing (as stated): Open source · Mature
24. CubeSandbox
Lightweight, concurrent sandbox for running AI agent code securely.
Pricing (as stated): Open source · Mature
25. IDA Pro MCP
MCP server connecting IDA Pro to language models for AI-assisted reverse engineering.
Pricing (as stated): Open source · Mature
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Related: Best MCP servers (all) · for Claude Code · for Cursor · for Codex
More best-of lists: All best lists · Best AI Coding Agents · Best AI Agent Frameworks · Best AI Browser Agents · Most-Starred Open-Source AI Agent Projects · Best Self-Hosted AI Agents · Best Free AI Agents (Free Plans) · Best No-Code AI Agent Builders · Best AI Voice Agent Platforms · Best AI Vision Tools for Agents · Best AI Agent Observability & Eval Tools · Best Personal AI Agents · Best AI Agents for Business Teams · Best Crypto AI Agents · Best AI Productivity Agents
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.