A2A is shorthand, not a guarantee
In practice, teams use A2A to describe agents that can coordinate with other agents, expose structured capabilities, or participate in a broader multi-agent workflow. That is useful, but it is not precise enough on its own.
A buyer should still ask what protocol is used, how authentication works, what inputs and outputs are supported, and whether the agent is hosted, self-hosted, or delivered as source.
Compatibility has to be concrete
A real A2A-compatible listing should expose the parts that matter for integration: endpoint access, agent card or schema references, interaction modes, rate limits, and any required external services.
Without those details, the label becomes marketing copy instead of an implementation clue. The marketplace should surface these fields so buyers can compare agents with confidence.
Directories matter because the category is still forming
A2A is early. Discovery is fragmented. That makes curated directories valuable because they standardize the surrounding buying context even when the ecosystem language is still unstable.
The best A2A directories will help buyers understand not just which agents exist, but how each one fits into a real production workflow.