Retrieves the full details for a specific agent, including the inputs required to run it. Call this endpoint before starting a run. The expected input is defined in inputSchema, which describes the message parts the agent accepts, such as text or structured data, and whether each part is required.

For structured input, the schema defines the payload that must be provided in the corresponding data part of Start Agent Run. inputSchema is returned only by this endpoint and is not included in List Agents. It is omitted when the agent does not define an input contract.