Slack

Post and manage Slack messages, channels, reactions, and users from inside an agent workflow.

Slack actions let an agent work with a workspace directly in a flow. An agent can post, update, delete, and search messages, manage channels, add reactions, and look up users, then pass the results to later steps.

Supported actions

Group	Actions
Message	Post, Update, Delete, Search
Channel	Create, Get, Get All
Reaction	Add
User	Info, Get All

Prerequisites

Create a Slack credential

Store a Slack bot token (or a Slack OAuth connection) as a Slack credential in Credential Management, then select it on every Slack action. The Message Search action is the exception. It requires a credential backed by a Slack user token rather than a bot token, so store a separate user token credential for any flow that uses search.

How to use these actions

• Map text inputs from earlier steps. Inputs such as Channel, Text, and Query accept a value mapped from a previous step.
• Toggles and counts take fixed values. The Is Private, Exclude Archived, Reply Broadcast, Unfurl Links, and Unfurl Media toggles, along with Limit and Count, are set to fixed values.
• Messages are addressed by channel and timestamp. To update, delete, or react to a message, supply its channel ID and its message Timestamp.
• Reply in a thread. Set Thread Timestamp on Message Post to the timestamp of a parent message so the new message lands in that thread.
• Search needs a user token. Message Search requires a credential backed by a Slack user token. The other actions use a bot token.
• Reaction names omit colons. Use the emoji name without surrounding colons, for example thumbsup.

Actions

Message

Slack Message Post

Posts a message to a channel, group, or user.

Input	Required	Description
Channel	Yes	The channel, group, or user ID to post to.
Text	Yes	The message text. Supports Slack mrkdwn formatting.
Thread Timestamp	No	The timestamp of a parent message to reply to.
Reply Broadcast	No	Toggle. When on, also posts a threaded reply to the channel. Defaults to off.
Unfurl Links	No	Toggle. Whether to show previews for links. Defaults to on.
Unfurl Media	No	Toggle. Whether to show previews for media. Defaults to on.

Slack Message Update

Updates an existing message.

Input	Required	Description
Channel	Yes	The channel, group, or user ID the message is in.
Timestamp	Yes	The timestamp of the message to update.
Text	Yes	The new message text.

Slack Message Delete

Deletes a message.

Input	Required	Description
Channel	Yes	The channel, group, or user ID the message is in.
Timestamp	Yes	The timestamp of the message to delete.

Slack Message Search

Searches for messages across the workspace.

Input	Required	Description
Query	Yes	The search query. Supports modifiers like from:, in:, and has:.
Sort Direction	No	Sort order, either asc or desc. Defaults to desc.
Count	No	Maximum number of results to return, from 1 to 100. Defaults to 20.

Channel

Slack Channel Create

Creates a new channel.

Input	Required	Description
Name	Yes	The channel name. Lowercase, no spaces, up to 80 characters.
Is Private	No	Toggle. When on, creates a private channel. Defaults to off.

Slack Channel Get

Retrieves a single channel.

Input	Required	Description
Channel ID	Yes	The unique identifier of the channel to retrieve.

Slack Channel Get All

Lists channels in the workspace.

Input	Required	Description
Exclude Archived	No	Toggle. When on, omits archived channels. Defaults to off.
Limit	No	Maximum number of channels to return, from 1 to 1000. Defaults to 100.
Types	No	Comma separated list of channel types to include. One or more of public_channel, private_channel, mpim, and im.

Reaction

Slack Reaction Add

Adds an emoji reaction to a message.

Input	Required	Description
Channel	Yes	The channel, group, or user ID the message is in.
Timestamp	Yes	The timestamp of the message to react to.
Name	Yes	The emoji name without colons, for example thumbsup.

User

Slack User Info

Retrieves a single user.

Input	Required	Description
User ID	Yes	The unique identifier of the user to retrieve.

Slack User Get All

Lists the users in the workspace.

Input	Required	Description
Limit	No	Maximum number of users per page, from 1 to 1000. Defaults to 100.

Example

An agent that posts an alert and confirms it in a thread:

1. Post the alert

   A Slack Message Post action sets Channel to the alerts channel and maps Text to a summary built by an earlier model step.

2. Reply in the thread

   A second Slack Message Post action sets Thread Timestamp to the timestamp returned by the first post, then adds follow up detail in that thread.

3. Acknowledge

   A Slack Reaction Add action sets Channel and Timestamp to the original message and adds the eyes reaction to show the alert was seen.

Troubleshooting

Not authed or invalid auth

The stored token is missing, expired, or revoked. Confirm the credential holds a valid bot token, or a user token for Message Search, and reconnect if needed.

Missing scope

The token lacks a required scope for the action, such as chat:write to post or search:read to search. Add the scope in your Slack app configuration and reinstall.

Search returns nothing

Message Search needs a credential backed by a user token, not a bot token. Confirm the search action uses the user token credential and that the query modifiers are valid.

Channel not found

The channel ID does not exist or the bot is not a member of it. Invite the bot to private channels before posting, and confirm the channel ID rather than the channel name.

For issues common to every vendor, see the Actions overview.