11 Best Open-Source Agent Protocols & Standards in 2026 (Ranked by GitHub Activity)
Open standards and protocols defining how agents communicate with tools and collaborate with other agents
Top picks right now: CopilotKit, AG-UI, LibreChat. Every tool below is open source and ranked by live GitHub activity (stars, 30-day star growth, commits and releases), refreshed daily.
11 tools
CopilotKit
open-sourceThe Frontend Stack for Agents & Generative UI. React + Angular. Makers of the AG-UI Protocol
AG-UI
open-sourceAG-UI: the Agent-User Interaction Protocol. Bring Agents into Frontend Applications.
LibreChat
open-sourceOpen-source ChatGPT-like interface for multiple AI models, agents, and sandboxed code execution
Model Context Protocol
freeSpecification and documentation for the Model Context Protocol
Casibase
open-sourceOpen-source AI knowledge base and MCP/A2A management platform with admin UI, user management, and SSO
A2A
open-sourceAgent2Agent (A2A) is an open protocol enabling communication and interoperability between opaque agentic applications.
Khazix Skills
open-source数字生命卡兹克开源的 AI Skills 合集 | Agent Skills: leader（帮你定义目标）, neat-freak 洁癖, hv-analysis, khazix-writer & more — Claude Code, Codex & 40+ agents
Bindu
open-sourceBindu: The identity, communication, and payments layer for AI agents.
OpenAI Developers Responses API reference
open-sourceOpenAPI specification for the OpenAI API
emcee
open-sourceMCP generator for OpenAPIs 🫳🎤💥
agent protocol
open-sourceCommon interface for interacting with AI agents. The protocol is tech stack agnostic - you can use it with any framework for building agents.