Slack Connection
Connect Horizon to Slack so agents can hold conversations in a channel — connect the workspace, then give each agent its channel.
The Slack connection lets your Horizon agents work in Slack: reading messages in the channel they are given and replying there.
Setting it up takes two steps in two different places. Connecting the workspace is the first; it is not sufficient on its own.
Prerequisites
- A Slack workspace where you can approve app installations.
Step 1 — Connect the workspace
- Navigate to Workspace > Connections and click Connect Service.
- Select Slack from the list.
- Click Connect. You will be redirected to Slack’s authorization page.
- Choose the workspace to connect, review the permissions, and click Allow.
- You are returned to Horizon and the Slack card appears in your connections.
Step 2 — Give an agent its channel
Connecting the workspace does not put any agent into any channel. Each agent gets its channel when you deploy it, in that agent’s messaging setup — you either pick an existing channel or have Horizon create a new one for it.
An agent with no channel has nowhere to talk, so this step is not optional.
Because the channel belongs to the agent rather than to the connection, two agents can work in two different channels over the same Slack connection, and moving an agent to a new channel is a change to the agent, not to the connection.
The Horizon Bot
Authorizing the connection installs a bot user in your workspace. It appears in your app list as Horizon, and Horizon can add it to the channel an agent is assigned, creating that channel first if you asked for a new one.
The bot only sees channels it is a member of. It cannot read a channel it has not been added to.
What Agents Can Do
With the Slack connection, agents can:
- Read new messages in their channel and reply there.
- Respond to a mention of the Horizon bot.
- Post updates and notifications — including alerts arising from other integrations.
- Handle a shared file — a message that shares a file reaches the agent along with the message.
Horizon also creates channels, invites members, lists channels, and looks a user up by email address in support of the above.
Several things Slack apps commonly do are not part of this integration: there are no slash commands, no emoji reactions, and no reading of channel history. Message edits, message deletions, reaction events and channel events such as members joining are received and discarded — only a plain new message reaches an agent.
Troubleshooting
| Issue | Resolution |
|---|---|
| Bot does not respond in a channel | Confirm the bot is a member of that channel, and that the channel is the one assigned to the agent. |
| Agent connected but silent | Check the agent has a messaging channel set. A Slack connection alone does not give an agent a channel. |
| Messages not appearing | Check Slack admin policies are not restricting the app. |
| Editing a message does nothing | Expected. Only new messages reach an agent; edits are discarded. |
Connection shows expired or requires_reconnection | Click Disconnect on the connection’s card, then Connect Service and set it up again. There is no re-authorize button. |
Disconnecting
Click Disconnect on the Slack card in Workspace > Connections and confirm.
To also remove the app from Slack, go to Slack › Settings › Manage Apps and remove Horizon.