> ## 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.

# Start a discussion

<Snippet file="graphql/sdk-note.mdx" />

Opening a discussion attaches a new side-conversation to an existing thread. The `type` determines where messages are exchanged:

* `SLACK` — posts a new Slack thread in a [connected Slack channel](https://plain.support.site/article/slack-channels). Requires `slackDetails.connectedSlackChannelId`.
* `EMAIL` — sends a new email to one or more recipients. Requires `emailDetails.toAddresses`.

The `markdownContent` is the first message of the discussion. For Slack discussions you can also pass `slackBlocks` (a JSON-encoded [Slack Block Kit](https://api.slack.com/block-kit) array) to render rich content in Slack; `markdownContent` remains the fallback rendered in Plain.

<Snippet file="graphql/create-thread-discussion.mdx" />