npm package: @memberjunction/a2aserver
Description: MemberJunction Agent-To-Agent (A2A) Server Implementation
Author: MemberJunction
Latest version: 5.24.0

# @memberjunction/a2aserver

MemberJunction implementation of the Google Agent-to-Agent (A2A) protocol server. Exposes MemberJunction AI agents and entity operations as A2A-compliant capabilities, enabling interoperability with other A2A-compatible agents across different platforms and frameworks.

## Architecture

```mermaid
graph TD
    subgraph "@memberjunction/a2aserver"
        SRV["A2A Server<br/>Express HTTP"]
        style SRV fill:#2d8659,stroke:#1a5c3a,color:#fff

        CFG["Config<br/>mj.config.cjs"]
        style CFG fill:#b8762f,stroke:#8a5722,color:#fff

        subgraph "Operations"
            AO["AgentOperations<br/>AI Agent Execution"]
            style AO fill:#7c5295,stroke:#563a6b,color:#fff

            EO["EntityOperations<br/>CRUD on Entities"]
            style EO fill:#7c5295,stroke:#563a6b,color:#fff
        end

        subgraph "A2A Protocol"
            AC["Agent Card<br/>/.well-known/agent.json"]
            style AC fill:#2d6a9f,stroke:#1a4971,color:#fff

            TS["Task System<br/>Create, Query, Cancel"]
            style TS fill:#2d6a9f,stroke:#1a4971,color:#fff

            MSG["Messages<br/>User & Agent Parts"]
            style MSG fill:#2d6a9f,stroke:#1a4971,color:#fff

            ART["Artifacts<br/>Structured Output"]
            style ART fill:#2d6a9f,stroke:#1a4971,color:#fff
        end
    end

    SRV --> AO
    SRV --> EO
    SRV --> AC
    SRV --> TS
    TS --> MSG
    TS --> ART

    subgraph "A2A Clients"
        C1["A2A Client Agent"]
        style C1 fill:#b8762f,stroke:#8a5722,color:#fff
        C2["Orchestrator"]
        style C2 fill:#b8762f,stroke:#8a5722,color:#fff
    end

    C1 -->|"HTTP / SSE"| SRV
    C2 -->|"HTTP / SSE"| SRV

    subgraph "MJ Backend"
        AIE["AIEngine"]
        style AIE fill:#2d6a9f,stroke:#1a4971,color:#fff
        AIA["AI Agents"]
        style AIA fill:#2d6a9f,stroke:#1a4971,color:#fff
        MJE["MJ Entities"]
        style MJE fill:#2d6a9f,stroke:#1a4971,color:#fff
    end

    AO --> AIA
    EO --> MJE
    AO --> AIE
```

## About the A2A Protocol

Agent-to-Agent (A2A) is an open protocol developed by Google that enables communication and interoperability between opaque agentic applications. It provides a standardized way for agents built on different platforms to discover, communicate with, and delegate tasks to each other.

- [Official A2A Documentation](https://google.github.io/A2A/)
- [A2A Protocol Specification](https://google.github.io/A2A/specification/)
- [GitHub Repository](https://github.com/google/A2A)

## Installation

```bash
npm install @memberjunction/a2aserver
```

## Quick Start

```bash
# Start the A2A server (default port 3200)
npx @memberjunction/a2aserver
```

## Key Features

### Agent Card Discovery

The server publishes an Agent Card at `/.well-known/agent.json` following the A2A specification. The card describes the server's capabilities, supported skills, and authentication requirements.

### Task-Based Interaction

All interactions follow the A2A task model:

```mermaid
stateDiagram-v2
    [*] --> pending: Create Task
    pending --> in_progress: Start Processing
    in_progress --> completed: Success
    in_progress --> failed: Error
    in_progress --> cancelled: Cancel Request
    completed --> [*]
    failed --> [*]
    cancelled --> [*]

    classDef stateStyle fill:#2d6a9f,stroke:#1a4971,color:#fff
    class pending,in_progress stateStyle
```

### Entity Operations

CRUD operations on MemberJunction entities exposed through A2A:

| Operation | Description |
|---|---|
| `Get` | Retrieve a single entity record by primary key |
| `Create` | Create a new entity record |
| `Update` | Update an existing entity record |
| `Delete` | Delete an entity record |
| `Query` | Search/filter entity records with RunView |

### Agent Operations

Execute MemberJunction AI agents through A2A tasks:

- Send messages to agents via A2A task creation
- Receive agent responses as A2A message parts
- Track execution status through task lifecycle
- Access agent artifacts (structured outputs)

### Server-Sent Events (SSE)

Streaming support for long-running agent operations. Clients can subscribe to task updates via SSE for real-time status and message delivery.

## A2A Protocol Endpoints

| Endpoint | Method | Description |
|---|---|---|
| `/.well-known/agent.json` | GET | Agent Card discovery |
| `/tasks/send` | POST | Create a new task |
| `/tasks/sendSubscribe` | POST | Create task with SSE subscription |
| `/tasks/{id}` | GET | Query task status |
| `/tasks/{id}/cancel` | POST | Cancel a running task |

## Configuration

Configure via `mj.config.cjs`:

```javascript
module.exports = {
    a2aServerSettings: {
        port: 3200
    },
    databaseSettings: {
        host: 'localhost',
        port: 1433,
        database: 'MemberJunction',
        username: 'sa',
        password: 'password'
    }
};
```

Required environment variables:
- `DB_HOST`, `DB_PORT`, `DB_DATABASE`, `DB_USERNAME`, `DB_PASSWORD` -- Database connection
- `AI_VENDOR_API_KEY__*` -- AI provider API keys

## Message Format

A2A messages contain typed parts:

```typescript
// Text part
{ type: 'text', content: 'Analyze sales data for Q3' }

// File part
{ type: 'file', content: '<base64-encoded-data>', metadata: { mimeType: 'application/pdf' } }

// Data part (structured)
{ type: 'data', content: { key: 'value' } }
```

## Dependencies

- `@memberjunction/ai-agents` -- AgentRunner for agent execution
- `@memberjunction/ai-core-plus` -- Extended entity classes
- `@memberjunction/aiengine` -- AIEngine for metadata
- `@memberjunction/ai` -- Core AI abstractions
- `@memberjunction/server` -- MJ server authentication
- `@memberjunction/server-bootstrap-lite` -- Class registration manifest
- `@memberjunction/sqlserver-dataprovider` -- SQL Server data access
- `@memberjunction/api-keys` -- API key management
- `@memberjunction/config` -- Configuration loading
- `@memberjunction/encryption` -- Data encryption
- `express` -- HTTP server framework
- `zod` -- Schema validation