Specification Overview
LAD-A2A defines how AI agents discover each other on local networks.
Current Version
v0.1.0-draft (January 2025)
Core Concepts
Discovery Mechanisms
LAD-A2A supports multiple discovery paths with automatic fallback:
| Priority | Mechanism | Use Case |
|---|---|---|
| 1 | mDNS/DNS-SD | Zero-config LAN discovery via _a2a._tcp |
| 2 | Well-Known Endpoint | HTTP-based via /.well-known/lad/agents |
| 3 | DHCP Option | Enterprise networks |
| 4 | QR/NFC | Human-assisted fallback |
Security Model
Local networks are hostile by default. LAD-A2A mandates:
| Requirement | Description |
|---|---|
| TLS Required | All endpoints must use HTTPS |
| Signed AgentCards | JWS or DID-based verification |
| User Consent | Explicit approval before connection |
| Capability Scopes | Least-privilege enforcement |
Discovery Flow
1. Device joins network
2. Client queries mDNS (_a2a._tcp) or well-known endpoint
3. Discovery response includes AgentCard URL
4. Client fetches and verifies AgentCard
5. User approves connection
6. Standard A2A session begins
Documents
- Full Specification - Complete protocol details
- JSON Schemas - Response format definitions
Related Protocols
| Protocol | Role | Link |
|---|---|---|
| A2A | Agent-to-Agent Communication | a2a-protocol.org |
| MCP | Agent-to-Tools/Data | modelcontextprotocol.io |