ai.PromptMessage

The chat role, e.g. "system", "user", or "assistant". Empty for role-less content.

The message's rendered text. Media parts use a readable placeholder; a cache delimiter contributes nothing.

Ordered structural content. Provider clients use this instead of the readable content projection so media survives prompt rendering.

Free-form per-message data, carried verbatim from the ai.Role.metadata of the ${role(...)} marker that opened this message. Empty when the message carried none. The built-in clients do not read it.