When Does the A2A Protocol Actually Matter?

This post clarifies the practical application of the A2A protocol, emphasizing that its value is primarily realized when agents owned by different teams or vendors need to communicate across trust boundaries. It contrasts this with internal agent coordination, where orchestration frameworks and MCP are often sufficient. The post details A2A's core primitives (Agent Card, Task, Message, Part, Artifact) and its transport-agnostic nature. It highlights the security model, which relies on external identity providers and standard web transport security (HTTPS, OAuth), and the need for explicit identity and authorization at trust boundaries. The post also discusses the evolving landscape of delegated authentication and identity chaining standards, and notes that while A2A has broad industry support, its production prevalence is still being determined.