# Agent2Agent Protocol (A2A) [Announcing the Agent2Agent Protocol (A2A) - Google Developers Blog](https://developers.googleblog.com/en/a2a-a-new-era-of-agent-interoperability/) > A new era of Agent Interoperability A2A is an open protocol that complements Anthropic's Model Context Protocol (MCP), which provides helpful tools and context to agents. design principles: - Embrace agentic capabilities - Build on existing standards - Secure by default - Support for long-running tasks - Modality agnostic key capabilities: - Capability discovery - "Agent Card" in JSON format - Task management - The output of a task is known as an "artifact." - Collaboration - User experience negotiation