Developer Tool Compares A2A Agent Cards Across AWS, GCP, and Azure Clouds

A developer tutorial published on August 25, 2026, demonstrates how to fetch and compare Agent Card metadata from A2A-protocol agents running on three major cloud platforms: AWS Bedrock AgentCore, Google Cloud Run, and Azure Container Apps. An Agent Card is a JSON document hosted at a standard path that describes an agent's name, skills, and endpoint details, and is the first thing a client reads before connecting. The project only performs discovery — it never invokes the agents, sends prompts, or incurs any token costs. A key finding is that only AWS Bedrock AgentCore separates card-discovery permissions from invocation permissions via a distinct IAM action, while Cloud Run and Azure Container Apps bundle both behind a single access role. The accompanying open-source repository includes injectable test transports to simulate edge cases such as authentication denials and legacy card paths without requiring live cloud environments.