Skill: A2A Multi-Agent Orchestration

Turn XActions into an A2A-compatible agent that can discover, communicate with, and delegate tasks to other AI agents using Google's Agent-to-Agent protocol.

When to Use

User wants to connect XActions with external AI agents
User needs multi-agent orchestration (decompose → delegate → aggregate)
User asks about A2A protocol, agent cards, or inter-agent communication
User wants to run the A2A server or manage agent discovery
User needs real-time task streaming between agents

Files

File	Purpose
`src/a2a/types.js`	Shared constants, factories, validators
`src/a2a/skillRegistry.js`	MCP tool → A2A skill bridge
`src/a2a/agentCard.js`	Agent Card generation (`.well-known/agent.json`)
`src/a2a/taskManager.js`	Task lifecycle (create, transition, execute)
`src/a2a/bridge.js`	A2A ↔ MCP translation layer + NLP
`src/a2a/streaming.js`	SSE streaming for real-time updates
`src/a2a/push.js`	Webhook push notifications
`src/a2a/auth.js`	API key + JWT inter-agent auth
`src/a2a/discovery.js`	Agent registry, skill matching, trust scoring
`src/a2a/orchestrator.js`	Task decomposer + delegator + orchestrator
`src/a2a/server.js`	Express HTTP server (port 3100)
`src/a2a/index.js`	Barrel export + CLI commands + factory
`dashboard/a2a.html`	Web dashboard for monitoring

Quick Start

Start the A2A server

# Via CLI
node src/a2a/server.js

# Directly
node src/a2a/server.js

# With session cookie for browser automation
node src/a2a/server.js --cookie "YOUR_X_SESSION_COOKIE"

Check health

curl http://localhost:3100/a2a/health

View Agent Card

curl http://localhost:3100/.well-known/agent.json

Send a task

curl -X POST http://localhost:3100/a2a/tasks \
  -H "Content-Type: application/json" \
  -d '{
    "jsonrpc": "2.0",
    "method": "tasks/send",
    "params": {
      "message": {
        "role": "user",
        "parts": [{"type": "text", "text": "get profile for @nichxbt"}]
      }
    },
    "id": "1"
  }'

Discover an agent

curl -X POST http://localhost:3100/a2a/agents/discover \
  -H 'Content-Type: application/json' \
  -d '{"url": "https://other-agent.example.com"}'

List skills

curl http://localhost:3100/a2a/skills
curl 'http://localhost:3100/a2a/skills?query=scrape'

Architecture

┌─────────────────────────────────────────────────────┐
│                   A2A Protocol Layer                 │
│  ┌──────────┐  ┌──────────┐  ┌──────────────────┐  │
│  │  Agent    │  │   Task   │  │   Streaming /    │  │
│  │  Card     │  │  Manager │  │   Push Notify    │  │
│  └────┬─────┘  └────┬─────┘  └────────┬─────────┘  │
│       │              │                 │             │
│  ┌────┴──────────────┴─────────────────┴──────────┐ │
│  │              HTTP Server (Express)              │ │
│  └────────────────────┬────────────────────────────┘ │
│                       │                              │
│  ┌────────────────────┴────────────────────────────┐ │
│  │        Bridge (A2A ↔ MCP Translation)           │ │
│  └────────────────────┬────────────────────────────┘ │
│                       │                              │
│  ┌────────────────────┴────────────────────────────┐ │
│  │           Skill Registry (140+ tools)           │ │
│  └─────────────────────────────────────────────────┘ │
│                                                      │
│  ┌─────────────┐  ┌────────────┐  ┌──────────────┐  │
│  │  Discovery  │  │   Auth     │  │ Orchestrator │  │
│  │  + Trust    │  │  (JWT/Key) │  │ (Decompose)  │  │
│  └─────────────┘  └────────────┘  └──────────────┘  │
└──────────────────────────────────────────────────────┘

Key Concepts

Agent Card

Every A2A agent publishes a JSON document at /.well-known/agent.json describing its capabilities, skills, and supported protocols.

Skills

XActions converts its 153 MCP tools into A2A skills, each with a unique ID (xactions.<tool_name>), description, input schema, and category tags.

Task Lifecycle

submitted → working → completed
                   → failed
         → canceled
         → input-required → working

Trust Scoring

Remote agents are scored 0-100 based on success ratio (40%), longevity (20%), recency (20%), and volume (20%).

Task Decomposition

Complex natural-language tasks are automatically broken into ordered sub-tasks with dependency tracking ($step1, $step2.field).

Endpoints

Method	Path	Description
GET	`/.well-known/agent.json`	Agent Card
POST	`/a2a/tasks`	Create task (tasks/send or tasks/sendSubscribe)
GET	`/a2a/tasks/:id`	Get task
POST	`/a2a/tasks/:id/cancel`	Cancel task
GET	`/a2a/tasks/:id/stream`	SSE stream
POST	`/a2a/tasks/:id/message`	Push notification
GET	`/a2a/health`	Health check
GET	`/a2a/skills`	List skills
POST	`/a2a/orchestrate`	Execute orchestrated task
POST	`/a2a/orchestrate/plan`	Get execution plan
GET	`/a2a/agents`	List discovered agents
POST	`/a2a/agents/discover`	Discover remote agents

Running and driving the server

The CLI has no A2A subcommand. The A2A agent is an HTTP server, and every operation is one of the endpoints in the table above.

# Start it (defaults to port 3100)
node src/a2a/server.js

# Or on another port, with a session attached
A2A_PORT=3200 XACTIONS_SESSION_COOKIE=your_auth_token node src/a2a/server.js

# Is it up?
curl http://localhost:3100/a2a/health

# What can it do?
curl http://localhost:3100/.well-known/agent.json
curl 'http://localhost:3100/a2a/skills?query=scrape'

# Which other agents does it know about?
curl http://localhost:3100/a2a/agents

# Give it a task
curl -X POST http://localhost:3100/a2a/orchestrate \
  -H 'Content-Type: application/json' \
  -d '{"task": "Scrape the profile of @nasa and summarise it"}'