> ## Documentation Index
> Fetch the complete documentation index at: https://www.plain.com/docs/llms.txt
> Use this file to discover all available pages before exploring further.

# importThreadDiscussion

> Import an existing external conversation as a discussion on a Plain thread, backfilling all messages.
Currently supports Slack threads via permalink — the entire thread (root message and all replies) is imported.
If the Slack channel is not yet connected to Plain, the bot will automatically join and register it as a
DISCUSSION channel (requires the connectedSlackChannel:edit permission). Private channels must have the
Plain bot invited via /invite @Plain first. The call is idempotent: re-importing the same Slack thread
onto the same Plain thread resumes from where the previous import left off; importing onto a different
thread returns an error. Threads with more than 800 messages cannot be imported.