A2a

Sends a message to an A2A-compliant agent at a URL or alias. Always runs in blocking mode. Pass --background to return immediately with a task ID instead. Resolves aliases, auth params, and timeout from settings. Tracks tasks in session.

Cancels an active A2A task. Resolves aliases and auth params from settings, updates session tracking.

Onboards a new A2A agent connection — fetches the Agent Card, checks prerequisites, and guides through saving the alias and configuring authentication. Use when the user wants to "discover", "onboard", "add", "register", or "connect" an A2A agent, or provides an agent URL they want to start using. Also triggers on "what can this agent do?" or "check the agent at <url>".

This skill provides the foundational A2A protocol knowledge Claude needs whenever a user wants to communicate with an A2A-compliant agent, call a remote agent by URL or alias, understand how agent cards work, integrate an agent-to-agent connection, construct an `a2a` CLI command, list or poll task status, cancel a running task, or subscribe to task updates. Relevant when the user mentions "A2A protocol", "agent card", "remote agent", "agent endpoint", "agent-to-agent", "a2a CLI", "use an agent", "call an agent", "ping an agent", or needs to understand task lifecycle states.