Skip to content
RI1 — Agent-to-Agent Protocol

A2A Protocol on Lambda

Four ops agents expose structured Agent Cards. Select an agent, send a task, watch the exchange. The CTO agent can delegate to the Security agent in real time via A2A.

Invoke an Agent

Select an agent, write a task, click Invoke.
Rate limits: 10 requests/IP/hour • 50 exchanges/day global. CTO agent uses Claude Haiku.
🌐

A2A Discovery Endpoints

GET /.well-known/agent-registry
GET /agents/{id}
POST /agents/{id}
GET /sessions/{id}
GET /sessions

Message Exchange Trace

No exchanges yet.
Invoke an agent to see the A2A message trace.

What this demonstrates

Agent Cards
Each agent publishes a machine-readable card: identity, capabilities, input/output schema, rate limits. A2A clients discover agents at /.well-known/agent-registry before invoking.
Structured delegation
The CTO agent doesn't call security APIs directly. It delegates to the Security agent via a typed TaskRequest. The Security agent returns a TaskResponse. Both exchanges are logged.
Session tracing
Every invocation creates a session. Each agent-to-agent call is an exchange record in DynamoDB. The session ID lets you replay the full interaction graph.
No framework required
This is a Python Lambda function with no A2A SDK. The protocol is just structured JSON over HTTP POST with a discovery endpoint. 200 lines implements the full spec.

Read the companion article: A2A protocol in 200 lines of Lambda