Image message for the MCP (Model Context Protocol) agent (e.g. a rendered chart). Payload is base64-encoded binary data with its mime type.
id: MCPMessageId
Unique identifier for the message (used to track delivery and deduplication)
type: "image"
Discriminator for type-safe union
mimeType: string
Mime type of the encoded payload (e.g., "image/png")
data: string
Base64-encoded binary data of the image