You can read event tags to get information about an active Slack conversation:

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Slack conversation ID

To get the Slack conversation ID: event.tags.conversation["slack:id"]

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Slack thread ID

To get the Slack conversation thread ID (if it’s a thread): event.tags.conversation["slack:thread"]

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Slack user ID

To get the Slack user ID: event.tags.user["slack:id"]

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Slack message ID

To get the Slack message ID: event.tags.message["slack:id"]