// Protocols, specs & agent payments
Follow protocols & specs
Agent protocols and specs such as MCP and A2A, plus agent payments.
15 tools11 open sourcechecked 2026-10-22Compare side by side →
How to choose · start with these three
- · Tools: MCP; agent-to-agent: A2A; repo instructions: AGENTS.md
15 / 15 items
modelcontextprotocol 2026-07-28 ★ 9.5k Specification and documentation for the Model Context Protocol Open source Spec A2A v1.0.1 ★ 26k Agent2Agent (A2A) is an open protocol enabling communication and interoperability between opaque agentic applications. Open source Spec agents.md ★ 25k AGENTS.md — a simple, open format for guiding coding agents Open source Spec agentskills ★ 26k Specification and documentation for Agent Skills. Open source spec ucp ★ 3.4k Universal Commerce Protocol specification. Open source spec AG-UI ★ 17k An open, event-based Agent-User Interaction protocol that standardises how agent backends stream their run (about 16 standard event types) to user-facing apps; complements MCP (agent↔tools) and A2A (agent↔agent). Started by the CopilotKit team; scaffold with npx create-ag-ui-app Open source agent-client-protocol v1.11.0 ★ 4.4k A protocol for connecting any editor to any agent Open source SpecSDK MCP Apps ★ 3.0k Spec and SDK for MCP Apps, the official MCP extension that lets servers ship interactive UIs for their tools (charts, forms, dashboards) rendered inline in Claude, ChatGPT and other compliant chat clients; the repo ships four Agent Skills so a coding agent can scaffold an MCP App for you Open source llms-txt 0.0.7 ★ 2.7k The /llms.txt file, helping language models use your website Open source Spec a2a-python v1.2.2 ★ 2.2k Official Python SDK for the Agent2Agent (A2A) Protocol Open source SDK a2a-js v1.3.0 ★ 647 Official JavaScript SDK for the Agent2Agent (A2A) Protocol Open source SDK Agentic Commerce Protocol (ACP, OpenAI + Stripe) Open spec AP2 (Agent Payments Protocol) Open spec OpenTelemetry GenAI semantic conventions Open spec x402 Open spec
About this data
- Default order is “recommended”: editorial picks first, then by popularity; general-purpose developer software and archived projects are listed last.
- Data checked 2026-10-22. Official links only. JSON API