Agent2Agent
Agent2Agent, maintained by A2A project, Growth Stage project at the Agentic AI Foundation (Linux Foundation-directed). A protocol for agents to discover each other through an Agent Card and exchange tasks and messages. Status: Specification 1.0.0 is the latest release; joined the Agentic AI Foundation on 27 Aug 2026.
Fact sheet
| Name | Agent2Agent (A2A) |
|---|---|
| Maintainer | A2A project, Growth Stage project at the Agentic AI Foundation (Linux Foundation-directed) |
| What it is | A protocol for agents to discover each other through an Agent Card and exchange tasks and messages. |
| Status and version | Specification 1.0.0 is the latest release; joined the Agentic AI Foundation on 27 Aug 2026. |
| What it does not do | Does not define how an agent calls a plain API or a web page; it covers agent-to-agent tasks, not tool access. |
Dated facts
- A2A 1.0.0 defines three protocol bindings: JSON-RPC, gRPC and HTTP+JSON/REST, and allows custom bindings. (a2a-protocol.org, read 4 November 2026)
- The Agent Card is served at /.well-known/agent-card.json and registered as a well-known URI in section 14.3. (a2a-protocol.org, read 4 November 2026)
- A2A was accepted as a Growth Stage project at the Agentic AI Foundation on 27 Aug 2026, alongside MCP, goose and AGENTS.md. (a2a-protocol.org, dated 27 August 2026, read 4 November 2026)
- The spec page footer reads Copyright 2026 The Linux Foundation, Apache License 2.0. (a2a-protocol.org, read 4 November 2026)
- Kong AI Gateway emits OpenTelemetry metrics for A2A traffic alongside MCP. (developer.konghq.com, read 4 November 2026)
Seen in the shared crawl
| Path | Top 10,000 found | Ora leaderboard found |
|---|---|---|
/.well-known/agent-card.json | 10 of 7,470 (0.13%) | 48 of 3,368 (1.43%) |
/.well-known/agent.json | 6 of 7,461 (0.08%) | 14 of 3,366 (0.42%) |
A path counts only when the answer is the right kind of document. Many sites answer these paths with an ordinary web page, which is not counted. See the census.