Awesome Agent Protocols

A curated list of protocols and standards for AI agents.

🔌 wire protocol · 📐 spec / standard · 📄 format / convention · ⚠️ deprecated or merged

Foundations
Tool and context
Agent to agent
Agent to UI
Agent to editor
Serving and runtime
Identity and discovery
Agentic web
Payments and commerce
Formats and conventions
Governance
Surveys
Examples

Foundations

The editor-tooling protocols that predate agents. Same idea — decouple client from provider over JSON-RPC, collapse M×N to M+N.

Language Server Protocol (LSP) 🔌 - JSON-RPC standard for editor↔language-intelligence communication. The original M+N protocol; everything below copies this pattern. protocol
Debug Adapter Protocol (DAP) 🔌 - JSON-RPC for editor↔debugger, through an intermediary adapter. protocol
Build Server Protocol (BSP) 🔌 - Scala Center / JetBrains JSON-RPC for IDE↔build-tool (targets, compile, test, run). protocol

Tool and context

How an agent calls tools, reads data, and gets context.

Model Context Protocol (MCP) 🔌 - Anthropic. JSON-RPC 2.0 over stdio or Streamable HTTP. Connects LLM hosts to tools, resources, and prompts. Now under the Linux Foundation. protocol
- Tools 🔌 - tools/list + tools/call. JSON-Schema-typed callable functions. protocol
- Resources 🔌 - URI-addressed readable context (files, rows, blobs) with subscriptions. protocol
- Prompts 🔌 - Server-defined parameterized prompt templates, surfaced as slash commands. protocol
- Sampling 🔌 - Server asks the client for an LLM completion. Supports tool use + toolChoice. protocol
- Elicitation 🔌 - Server pauses to ask the user for input (forms) or hand off to the browser (OAuth, payments). protocol
- Roots 🔌 - Client declares which file:// paths servers may touch. protocol
- Apps (SEP-1865) 🔌 - Servers ship interactive HTML UI as ui:// resources, rendered in a sandboxed iframe. protocol
- Registry 📐 - Public server catalog + REST API. Standardized server.json publish format. spec/standard
OpenAI Apps SDK 🔌 - ChatGPT app = server logic + embedded widget. Converging with the MCP Apps extension. protocol
agents.json 📐 - Wildcard AI. Layered on OpenAPI — adds flows, links, and auth so agents can drive REST APIs. spec/standard
NLWeb 🔌 - Microsoft. Turns a website into a conversational, agent-queryable endpoint. protocol
Eclipse LMOS 🔌 - Deutsche Telekom / Eclipse Foundation. W3C Web of Things-based agent + tool discovery. protocol
SLOP 🔌 - Six REST endpoints (chat, tools, memory, resources, pay, info). Deliberately minimal. protocol
Arazzo 📐 - OpenAPI Initiative. YAML/JSON format for deterministic multi-step API workflows. spec/standard

Agent to agent

Cross-vendor, cross-framework agent collaboration.

Agent2Agent (A2A) 🔌 - Google / Linux Foundation. JSON-RPC 2.0 + SSE + Agent Card discovery. Stateful async task delegation between peer agents. protocol
Agent Communication Protocol (IBM ACP) 🔌 ⚠️ - IBM / BeeAI. REST-native agent messaging. Merged into A2A (Aug 2025). protocol
Agent Network Protocol (ANP) 🔌 - Decentralized P2P. W3C did:wba authentication, JSON-LD descriptions. protocol
Agora 🔌 - Oxford. Agents speak natural language for rare messages, then negotiate self-generated protocol docs for frequent ones. No central registry. protocol
AITP 🔌 - NEAR AI. Cross-trust-boundary Threads with pluggable capabilities for payments, decisions, on-chain identity. protocol
Coral 🔌 - MCP-native coordination. @mention-addressed threads, on-chain micropayments. protocol
HCS-10 OpenConvAI 🔌 - Agent messaging over Hedera Consensus Service topics. Tamper-proof, broker-less. protocol
ACNBP 🔌 - Draft academic. Discovery → negotiation → binding handshake with PKI signatures. protocol
W3C AI Agent Protocol CG 📐 - W3C community group for decentralized agent identity and discovery. Ships ANP. spec/standard

Agent to UI

Backend → frontend streaming of agent state, tool calls, and thinking.

AG-UI 🔌 - CopilotKit. Typed JSON events over HTTP/SSE from any agentic backend to any frontend. 9k+ GitHub stars. protocol
A2UI 🔌 - Google. Declarative generative-UI: JSON-Lines surface + data-model updates against a client widget catalog. protocol
AI SDK UI Stream Protocol 🔌 - Vercel. SSE of typed message parts (text, reasoning, tool, data) consumed by useChat. protocol

Agent to editor

The "LSP for agents" — editor/IDE ↔ coding agent.

Agent Client Protocol (ACP) 🔌 - Zed. JSON-RPC for editor↔agent. Adopted by Zed, JetBrains, VS Code, Kiro, Cline. Spoken by Gemini CLI, Claude, Codex. protocol
LSAP 🔌 - Turns LSP capabilities into high-level agent-native "cognitive" tools. protocol
Cody Agent Protocol 🔌 ⚠️ - Sourcegraph. Bidirectional JSON-RPC over stdio. Effectively frozen. protocol

Serving and runtime

How an agent is invoked as a service — runs, threads, state.

LangChain Agent Protocol 📐 - Framework-agnostic REST/OpenAPI. Agents, Runs, Threads, Store endpoints. spec/standard
Agent Connect Protocol (ACP) 📐 - AGNTCY / Cisco. OpenAPI spec for remote agent invocation, any framework. spec/standard

Identity and discovery

How agents are named, found, and trusted.

Agent Name Service (ANS) 📐 - OWASP. DNS-inspired discovery with PKI identity. Protocol-agnostic adapter over A2A, MCP, ACP. spec/standard
Project NANDA 📐 - MIT Media Lab. Federated "DNS for agents" — human-friendly handles → signed pointers → verifiable AgentFacts. spec/standard
AGNTCY Directory 🔌 - Cisco. Distributed, content-addressed registry. Signed OASF records as OCI artifacts over libp2p DHT. protocol
OASF 📐 - AGNTCY. OCI-based schema describing agent attributes, skills, capabilities. spec/standard
ERC-8004 📐 - On-chain agent identity, reputation, and validation via three Ethereum registry contracts. spec/standard
SPIFFE / SPIRE 📐 - CNCF. Short-lived cryptographic workload identities, no secrets at rest. Increasingly used for agent runtime identity. spec/standard
AgentDNS 📐 ⚠️ - Expired IETF draft. DNS-inspired naming + semantic discovery. Small reference impl. spec/standard
DNS-AID 📐 - IETF DNSOP draft. Publish/discover/verify agents through standard DNS records. Linux Foundation ref stack. spec/standard

Agentic web

Agents on the web — page tools, crawl permissions.

WebMCP 🔌 - W3C (Google, Microsoft). navigator.modelContext browser API exposing in-page tools to agents. protocol
Web-Agent Protocol (WAP) 📄 - Record browser interactions via extension, replay them for autonomous web agents. format/convention
TDMRep 📐 - W3C. Machine-readable mining permissions in HTTP headers, .well-known, or HTML. spec/standard

Payments and commerce

How agents pay — authorization, checkout, stablecoins.

AP2 🔌 - Google + 60 partners. A2A extension. Cryptographically signed Mandates for agent-led payments, cards + stablecoins. protocol
x402 🔌 - Coinbase / Linux Foundation. HTTP 402 with stablecoin payment in a header. Pay-per-call APIs. protocol
Agentic Commerce Protocol (ACP) 🔌 - OpenAI + Stripe. Agent-led checkout with Shared Payment Tokens. Powers Instant Checkout in ChatGPT. protocol
Universal Commerce Protocol (UCP) 📐 - Google + Shopify (Etsy, Target, Walmart, Wayfair). Product discovery through checkout. spec/standard
Cloudflare Pay Per Crawl 🔌 - HTTP 402 micropayments for AI crawlers, per request. protocol

Formats and conventions

Files, not messages. Often called "protocols" — they're not.

AGENTS.md 📄 - Project-specific instructions for coding agents. 60k+ repos. Agentic AI Foundation (Linux Foundation). format/convention
Agent Skills (SKILL.md) 📄 - Anthropic. Reusable agent capability as YAML frontmatter + instructions + optional scripts. format/convention
llms.txt 📄 - Markdown at site root listing LLM-readable content. Fetched by coding agents, not yet honored by major crawlers. format/convention
ai.txt 📄 - Usage permissions for AI (no-training, no-inference, allow-RAG). Sits next to robots.txt. format/convention
JSONL transcripts 📄 - One JSON object per line. How Claude Code, Codex, and others persist sessions. A log format, not a wire protocol. format/convention

Governance

Who stewards the open agent stack.

Agentic AI Foundation 📐 - Linux Foundation. Co-founded by Anthropic, Block, OpenAI. Homes MCP, AGENTS.md, Goose. spec/standard
Linux Foundation — A2A 📐 - Hosts A2A (+ absorbed IBM ACP), AP2, and related infra. spec/standard
OpenAPI Initiative 📐 - OpenAPI + Arazzo. The schema layer agent protocols build on. spec/standard

Surveys

A Survey of AI Agent Protocols - Two-dimensional taxonomy (context-oriented vs inter-agent, general vs domain-specific). Covers ANP, Agora, AITP, Coral.
A Survey of Agent Interoperability Protocols - Side-by-side of MCP, ACP, A2A, ANP across nine dimensions, with a phased adoption roadmap.

Examples

Wire-message examples in examples/: MCP tool calls, A2A Agent Cards, agents.json flows, LangChain Runs/Threads, x402 payments, AP2 mandates.

Skills

This repo ships a Claude Code skill that uses the catalog during development — recommends protocols, pulls wire examples, checks compliance, surfaces contribution opportunities.

Contributing

Read contributing.md first. By participating you agree to the Code of Conduct.

awesome-agent-protocols