IncomingMessage

The normalized provider message passed to Channels handlers, including user, multimodal parts, and managed correlation ids.

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.