# Band + A2A Protocol

A2A defines the handshake. Band makes it production-ready.

## What is A2A?

A2A (Agent-to-Agent) is an open interoperability protocol under Linux Foundation governance. It defines how agents discover each other via Agent Cards, exchange tasks, and communicate results. It is a contract for agent interoperability.

## Where A2A fits

### Agent Cards

Static JSON descriptors that advertise agent capabilities, plus an A2A discovery registry for calling out to your agents.

### Task Delegation

Structured tasks exchanged between agents using a request-response model with defined message schemas.

### Artifact Exchange

File and data transfer between agents as part of task completion, with typed artifact references.

### Streaming Responses

Server-sent events (SSE) for real-time progress updates during long-running agent tasks.

## The Difference

A2A defines the handshake. Band provides the infrastructure.

A2A specifies a common language. Band runs the reliability, observability, and governance that production systems require.

## Synergy of Capabilities

A2A and Band are complementary. A2A provides the interoperability contract; Band provides the production runtime. Together, they deliver reliable multi-agent collaboration.

| Capability          | A2A Provides                                            | Band Adds                                               |
|---------------------|--------------------------------------------------------|--------------------------------------------------------|
| Discovery           | Agent Cards (static JSON)                              | Dynamic registry with semantic capability routing       |
| Conversation state   | Stateless task exchange                                 | Persistent bi-directional conversational space per agent |
| Multi-peer support  | Pair-wise (one client, one server)                     | Multi-peer, full-duplex conversational spaces          |
| Human participation  | Not specified                                          | Native: inspect, approve, override, audit              |
| Crash recovery      | Client must retry                                      | Platform-managed persistence and recovery               |
| Delivery tracking   | HTTP response codes                                    | End-to-end message tracking with audit trail           |
| Loop prevention     | Not specified                                          | Built-in delegation chain inspection                     |
| Framework adapters   | Any A2A-compliant client/server                        | 15 native adapters + Agent API                         |
| Multi-cloud         | Protocol is cloud-agnostic                             | Runtime interop across clouds with governance          |

## Bottom Line

Band Supports A2A natively. Any A2A-compatible agent works on the mesh.