# Identity & protocols [Back to README](../README.md) | | Convention | Files | Read by | Spec | | --- | --- | --- | --- | --- | | 🟠 | [Agent Cards (A2A)](../conventions/agent-cards/) | `agent-card.json` `agent.json` _(pattern)_ | A2A-compatible agents discovering another agent's capabilities | [spec ↗](https://a2a-protocol.org/latest/specification/) | ## [Agent Cards (A2A)](../conventions/agent-cards/) The Agent2Agent (A2A) capability card - a JSON document at a well-known path advertising an agent's skills, endpoints, and auth so other agents can discover and call it. Now a Linux Foundation project at v1.0; adoption is growing but early.