IncomingMessage

IncomingMessage is the normalized inbound turn passed to onMessage, onMention, tools, and interaction contexts.

Shape

interface IncomingMessage {
  text: string;
  user: ApplicationUser | null;
  actor: ProviderActor;
  ref: MessageRef;
  platform: string;
  contentParts?: AgentContentPart[];
  eventId?: string;
  turnId?: string;
  deliveryId?: string;
}

Field	Managed Slack and Teams behavior
`text`	Provider text after ingress normalization.
`user`	Nullable application user returned by the Channel's `identifyUser` policy.
`actor`	Provider account that caused the event. It includes a required actor kind.
`ref`	In ordinary message handlers this may have an empty id; do not assume every inbound turn can be edited.
`platform`	Native source: `"slack"` or `"teams"` for message deliveries.
`contentParts`	Hydrated file/media parts when attachments were retrieved.
`eventId`	Stable provider-event id for application idempotency.
`turnId`	Managed turn correlation id.
`deliveryId`	Managed lease/delivery correlation id.

Multimodal prompt

const prompt = message.contentParts?.length
  ? [
      ...(message.text ? [{ type: "text" as const, text: message.text }] : []),
      ...message.contentParts,
    ]
  : message.text;

await thread.runAgent({ prompt });

Managed history excludes the current inbound turn. runAgent() injects the message automatically when prompt is omitted; use the explicit combined prompt above when a turn can contain both text and attachments. See Files and multimodal input.