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a2acli

Discovery & Identity

Discovery retrieves an agent’s AgentCard — its identity, description, supported interface protocols (gRPC, JSON-RPC, REST), available skills, and the security requirements for each skill. Everything else you do with a2acli builds on the card.

discover

Section titled “discover”

Fetch and display the A2A AgentCard for the target service.

Terminal window
a2acli discover
a2acli discover http://localhost:9001
a2acli discover --extended
a2acli discover --service-url http://localhost:9001 --extended

The agent URL can be passed either as an optional positional argument or via --service-url / -u (or its aliases --agent-card / --endpoint). With no URL, the default http://127.0.0.1:9001 is used.

Aliases: describe is accepted as a backwards-compatible alias, and card get is the noun-verb form (see below).

Flag Description
--extended Fetch the authenticated extended AgentCard via the GetExtendedAgentCard protocol RPC (requires a token; the agent must advertise extendedAgentCard: true)

The extended card is the richer, authenticated variant of the AgentCard. It requires a valid credential — see Configuration & Auth for how to obtain one with auth login.

card get

Section titled “card get”

card get is the noun-verb alias of the flat discover verb. It behaves identically — same flags, same output, same exit codes.

Terminal window
a2acli card get
a2acli card get http://localhost:9001
a2acli card get --extended

Use whichever grammar you prefer; the flat discover / describe verb remains available and unchanged. See the command model for more on the noun-verb grammar.

Section titled “Related”
  • Global flags reference — --service-url, --protocol, --transport, --no-cache, and the credential flags that apply to discovery.
  • Messaging & Tasks — once you have the card, send a message to the agent.