> ## Documentation Index
> Fetch the complete documentation index at: https://explore.airia.com/llms.txt
> Use this file to discover all available pages before exploring further.
# 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
Store a Slack bot token (or a Slack OAuth connection) as a **Slack** credential in [Credential Management](/admin-hub/account_settings/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:
A **Slack Message Post** action sets **Channel** to the alerts channel and maps **Text** to a summary built by an earlier model step.
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.
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
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.
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.
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.
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](/building-and-deploying-agents/agent-basics/actions/overview#troubleshooting).