A2A Server

What is A2A

A2A (Agent-to-Agent) is Google’s protocol for AI agents to communicate with each other. OSINT AI One exposes an A2A server that other agents can use to delegate investigation tasks.

Starting the server

osint-a2a               # default: 0.0.0.0:9000
osint-a2a --port 9090   # custom port

Agent Card

The server exposes its “agent card” at the standard endpoint:

GET http://localhost:9000/.well-known/agent-card.json

{
  "name": "OSINT AI Agent",
  "description": "Autonomous threat intelligence and OSINT investigation platform",
  "skills": [
    "investigate_ip",
    "investigate_domain",
    "investigate_url",
    "threat_feed_analysis",
    "risk_scoring"
  ],
  "version": "1.0.0",
  "streaming": true,
  "output_modes": ["json", "text"]
}

The 5 A2A Skills

Skill	Input	What it does
investigate_ip	IP address	Complete IP investigation with all tools
investigate_domain	Domain name	Complete domain investigation
investigate_url	URL	URL analysis with URLScan and context
threat_feed_analysis	Feed name + limit	Analyzes N most recent IOCs from a feed
risk_scoring	IOC	Returns only the risk score 0-100

Calling from another agent

from a2a_sdk import A2AClient

client = A2AClient("http://localhost:9000")

# IP investigation
result = await client.send_task({
    "skill": "investigate_ip",
    "message": "Investigate IP 185.220.101.34"
})

# With event streaming
async for event in client.stream_task({
    "skill": "investigate_domain",
    "message": "investigate domain evil-phishing.com"
}):
    print(f"Event: {event.type} — {event.data}")

Streaming

The A2A server supports real-time event streaming. While the agent investigates, it sends events:

{"type": "tool_call", "data": {"tool": "virustotal_ip_lookup", "input": "185.220.101.34"}}
{"type": "tool_result", "data": {"tool": "virustotal_ip_lookup", "result": {...}}}
{"type": "tool_call", "data": {"tool": "shodan_host_lookup", "input": "185.220.101.34"}}
{"type": "final", "data": {"assessment": "...", "risk_score": 94}}

This allows the client agent to show progress in real time.

Environment variables

A2A_HOST=0.0.0.0   # Listen interface
A2A_PORT=9000      # Port

Use cases

• Multi-agent orchestrator: a main agent delegates OSINT investigation to OSINT AI One and uses the results for decision-making
• Security pipeline: a SOAR system invokes A2A to automatically enrich alerts
• Triage agent: filters and prioritizes IOCs using risk_scoring before escalating to human analysts