Agent2Agent (A2A) protocol
An open protocol, launched by Google in April 2025, for agents from different vendors to discover each other and exchange tasks.
- Introduced by
- Introduced
- 2025-04
- Steward
- Linux Foundation
Connected
- GoogleGoogle division dedicated to artificial intelligence
- Model Context Protocol (MCP)An open protocol, introduced by Anthropic in November 2024, that standardises how AI applications connect to external tools and data sources.
- Agent Payments Protocol (AP2)Google's open protocol, announced in September 2025, for agents to make payments on a user's behalf using signed mandates.
Linked from
More agent tooling & protocols
- Claude CodeAnthropic's agentic coding tool that reads a codebase, edits files, runs commands and verifies its work from the terminal, IDE or web.
- agent-html-kitAn open-source template kit and Claude Code skill (kit.js) that lets agents emit content-only HTML components while design lives in one shared file, published with a 72-run HTML vs Markdown benchmark.
- CLAUDE.mdA Markdown file of standing instructions that Claude Code loads at the start of every session, at user, project and folder level.
- Karpathy-inspired CLAUDE.md rulesA widely starred public CLAUDE.md with four behaviour rules: think before coding, simplicity first, surgical changes and goal-driven execution.
- AGENTS.mdAn open, tool-neutral Markdown convention for giving coding agents project instructions, introduced by OpenAI in August 2025 and now stewarded by the Linux Foundation's Agentic AI Foundation.
- Claude Code hooksShell commands that Claude Code runs automatically at lifecycle events such as before or after a tool call, so rules can be enforced by code rather than requested in prose.