| Slack connected account | | Connected Account | Yes | |
| Channel ID | Channel, private group, or IM channel to send message to | Text (Short) | Yes | |
| Message | Content of the message being sent. Markdown can be used to apply styling. https://api.slack.com/reference/surfaces/formatting#basics | Text (Long) | Yes | |
| Attachment 1 | Attachment to include in the message | File | No | |
| Attachment 2 | Attachment to include in the message | File | No | |
| Attachment 3 | Attachment to include in the message | File | No | |
| Thread ID | Timestamp of the thread’s parent message. Use this to reply to a thread in Slack | Text (Short) | No | |
| Broadcast thread message? | Used in conjunction with Thread ID and indicates whether reply should be made visible to everyone in the channel or conversation | True/False | No | |