Slack

Connect Pencel to your Slack workspace so your agents can send messages, read channels, and look up team members. This is one of the most popular integrations — it turns your agents into active participants in your team's communication.

Trust Level	Partner
Transport	Remote (OAuth)
Endpoint	https://mcp.slack.com/mcp
OAuth	Embedded (one-click sign-in)
Activation	Auto-connect recommended

What Your Agent Can Do

Once connected, your agents have access to these Slack tools:

• Send messages to any channel or direct message thread.
• Read channel history to catch up on recent conversations.
• List channels to discover where discussions are happening.
• List users to look up team members by name or role.
• Reply to threads to keep conversations organized.
• Set channel topics to update team status boards.
• Search conversations to find past discussions.

Setup

Option A: One-Click OAuth (Recommended)

The fastest way to connect. Pencel handles the OAuth flow automatically.

1. Open Settings > Connections.
2. Click Add Connection and select Slack from the catalog.
3. Click Connect — your browser opens to Slack's authorization page.
4. Sign in and authorize Pencel.
5. Return to Pencel. Your connection card shows "Connected" with the available tools.

No bot tokens to create or manage. Pencel requests the scopes it needs (channels:read, channels:history, chat:write, search:read, users:read) during the OAuth flow.

Option B: Bot Token (Manual)

If you prefer to manage credentials yourself, you can connect with a Bot Token instead.

Step 1: Create a Slack Bot Token

1. Go to api.slack.com/apps and click Create New App.
2. Choose From scratch, give it a name (e.g., "Pencel"), and select your workspace.
3. Under OAuth & Permissions, add these Bot Token Scopes:
   • channels:read
   • channels:history
   • chat:write
   • users:read
   • groups:read (for private channels)
4. Click Install to Workspace and authorize the app.
5. Copy the Bot User OAuth Token (starts with xoxb-).

WARNING

Keep your Bot Token secret. Anyone with this token can read and post messages in your workspace. Pencel stores it securely in your operating system's keychain — it never leaves your machine.

Step 2: Add the Connection in Pencel

1. Open Settings > Connections.
2. Click Add Connection and select Slack from the catalog.
3. Paste your Bot Token into the credential field.
4. Click Connect.

Invite the Bot to Channels

Whether you used OAuth or a Bot Token, your Slack bot can only see channels it has been invited to. In each channel you want your agent to access:

1. Type /invite @Pencel (or whatever you named your app).
2. The bot now has read and write access to that channel.

TIP

Create a dedicated channel like #agent-updates for your agents to post to. This keeps automated messages separate from team conversations.

Example: Daily Standup Summary

Imagine you want an agent to post a daily summary of your team's standup updates.

Workflow setup:

1. Create a workflow called "Daily Standup Summary."
2. Add a step with these instructions:

Read the last 24 hours of messages from #daily-standup. Summarize what each team member is working on, any blockers mentioned, and overall team progress. Post the summary to #team-updates with a header "Daily Standup Summary — [today's date]."

3. Schedule the workflow to run every weekday at 10:00 AM.

The agent reads the standup channel, compiles the summary, and posts it — all without anyone needing to write it by hand.

Troubleshooting

Problem	Solution
"channel_not_found" error	Make sure the bot has been invited to the channel with /invite.
"not_authed" error	Your Bot Token may have expired or been revoked. Reconnect via OAuth or generate a new token.
Messages not appearing	Check that the bot has chat:write scope. With OAuth, this is granted automatically.
Can't read private channels	Add the groups:read and groups:history scopes to your Slack app, or reconnect via OAuth.
OAuth window does not open	Check that your default browser is set and not blocking pop-ups.