SendMessage

Task to send message to Slack channels or users with support for text, blocks, and link/media previews.

Task version: 2.0.0

Required Frends version: 5.7+

Required .NET version: 8.0

Compatible Agents: Crossplatform

Source code: https://github.com/FrendsPlatform/Frends.Slack/tree/main/Frends.Slack

Task Parameters

Input

Name	Description
ChannelId : String	The Slack channel or user ID. Default: - Example: C01234567 or U12345678
Mode : MessageMode	Message format mode. Possible values: PlainText: Plain text message Blocks: Richly formatted Block Kit message Default: - Example: PlainText
Text : String	The plain text of the message to send. Default: - Example: Hello from our integration!
Blocks : String	Slack Block Kit JSON for rich formatting. Default: - Example: [{ "type": "section", "text": { "type": "mrkdwn", "text": "Hello world!" } }]
ThreadTs : String	Timestamp of a message to reply in a thread. Default: - Example: 1234567890.123456

Connection

Name

Description

🗝Token : String

Slack OAuth token used for authentication. If the token is a bot token (starts with "xoxb"), messages will be sent as the Slack app's bot user. If the token is a user token (starts with "xoxp"), messages will be sent as the Slack user who authorized the token. Note: User tokens require the user to have authorized the app via OAuth with appropriate scopes (e.g., "chat:write"). Default: - Example: xoxb-123456789

Options

Name	Description
UnfurlLinks : Boolean	Whether to expand URLs in the message into rich previews (e.g. YouTube, websites). Note: Slack may unfurl a link only once per channel to reduce duplication. Default: True Example: true
UnfurlMedia : Boolean	Whether to show media previews (e.g. images, video thumbnails) for links in the message. Note: Media previews may appear only on first post of the same link. Default: True Example: true
ThrowErrorOnFailure : Boolean	True: Throw an exception. False: Error will be added to the Result.Error.AdditionalInformation list instead of stopping the Task. Default: True Example: true
ErrorMessageOnFailure : String	Message what will be used when error occurs. Default: Failed to send message to Slack Example: Task failed during execution

Task Result

Name	Description
Success : Boolean	Indicates whether the message was sent successfully. Example: true
MessageTs : String	The timestamp (ID) of the sent message. Example: 1234567890.123456
Error : Error	Error that occurred during task execution. Example: object { string Message, object { Exception Exception } AdditionalInfo }
Error.Message : String	Summary of the error. Example: Unable to join strings.
Error.AdditionalInfo : Exception	Additional information about the error. Example: object { Exception Exception }

Task Changelog

Changelog for Task Frends.Slack.SendMessage.

[2.0.0] - 2026-03-04

Fixed

• Blocks JSON string is now correctly parsed to JArray before sending to Slack API.
• [Breaking change] - Input.Blocks type changed from JArray to string. Users should now provide raw JSON string instead of parsed JArray.

[1.0.0] - 2025-06-03

Added

• Initial implementation