# Agent invocation

Use A2A-compatible Product API calls to discover an agent, send a message, save task identity, query task status and artifacts, and submit requested follow-up input.

An A2A invocation is asynchronous. Do not treat a successful HTTP response as task completion; save the returned task ID and inspect the task state and artifacts.

```{toctree}
:hidden:
:maxdepth: 1

Get an agent card <get-agent-card>
Call an agent <call-agent-a2a>
Query task status and artifacts <query-task-status-results>
Submit follow-up input <submit-follow-up-input>
```