CallMerlinDocs
Features

Slack Channel

Connect Slack as an inbound channel for CallMerlin.

Slack Channel

The Slack channel lets your employees chat with Merlin via Slack. Type @Merlin followed by a question in a Slack channel or send a DM, and Merlin replies with data from your connected services.

Availability

The Slack channel is available from the Professional plan onwards.

How it works

  1. An employee types @Merlin how many open invoices do I have? in a Slack channel
  2. Slack sends the message to CallMerlin
  3. Within 5-15 seconds Merlin replies in a thread
  4. Merlin has access to the same tools as webchat, phone and desktop

Requirements

  • A Professional plan or higher
  • A Slack workspace where you can install apps
  • Workspace owner or admin permissions in Slack

Setup

Step 1: Create a Slack App

  1. Go to api.slack.com/apps and click Create New App
  2. Choose From scratch
  3. Name the app (e.g. Merlin) and select your workspace
  4. Go to OAuth & Permissions and add these Bot Token Scopes:
    • app_mentions:read
    • chat:write
    • im:read
    • im:write
    • im:history
    • channels:history
    • users:read
  5. Click Install to Workspace and authorize the app
  6. Copy the Bot User OAuth Token (starts with xoxb-)

Step 2: Set up Event Subscriptions

  1. Go to Event Subscriptions in your Slack App settings
  2. Toggle Enable Events to On
  3. Paste the Request URL found in the CallMerlin dashboard under Slack channel
  4. Wait for Slack to verify the URL (green checkmark)
  5. Add these events under Subscribe to bot events:
    • app_mention
    • message.im
  6. Click Save Changes

Step 3: Configure the dashboard

  1. Go to callmerlin.app → Dashboard → Slack channel
  2. Enter the Bot Token (from step 1)
  3. Enter the Signing Secret (found under Basic Information → App Credentials)
  4. Click Test connection to verify everything works
  5. Choose a default PIN (optional, for employees without their own PIN)
  6. Toggle ON
  7. Click Save

Step 4: Send your first message

  1. Go to Slack
  2. Invite the bot to a channel: /invite @Merlin
  3. Type @Merlin hello
  4. Merlin replies in a thread

User mapping

Each Slack user is linked to a PIN code. The PIN determines which capabilities and template Merlin uses.

Assign a PIN

  1. Go to Slack channel in the dashboard
  2. Find the employee in the User mappings table
  3. Select a PIN from the dropdown
  4. The link is active immediately

Click Unlink next to an employee to remove the PIN mapping. The employee will fall back to the default PIN (if configured).

Default PIN

Set a default PIN for Slack users who have not been individually linked. New employees get access immediately without manual configuration.

Tip: Create a PIN with limited read-only permissions as the default. Assign broader permissions via individual mappings.

Channel filter

Restrict which Slack channels Merlin responds in. Useful if you don't want Merlin in all public channels.

  • Leave the field empty: Merlin responds in all channels
  • Enter specific channel IDs: Merlin responds only there

Context and follow-up questions

Merlin remembers conversation context for 15 minutes. Within this window you can ask follow-up questions in the same thread:

  • @Merlin how many invoices do I have? → Merlin replies with the count
  • and how many are overdue? → Merlin understands the context

After 15 minutes a new conversation starts without previous context.

Billing

Slack messages are billed as chat sessions:

  • First message = 0.5 minutes
  • Follow-ups within 15 minutes in the same thread = free (same session)
  • After 15 minutes = new session of 0.5 minutes

This is the same rate as webchat sessions.

Rate limits

To prevent abuse, hourly limits apply:

LimitValue
Per user20 messages per hour
Per channel50 messages per hour

When a limit is reached, Merlin tells you how many minutes to wait.

What can you ask?

Everything you can ask Merlin via webchat, phone or desktop also works in Slack. Examples:

  • @Merlin how many open invoices do I have?
  • @Merlin create a draft invoice for Baker Ltd, $2500 excl. VAT
  • @Merlin what's on my calendar tomorrow?
  • @Merlin how does our return policy work?

Limitations

  • Merlin cannot send files or use Slack Block Kit cards
  • Replies are limited to 3000 characters
  • Threading: Merlin always replies in a thread (DMs are an exception)

Troubleshooting

Merlin doesn't respond

  1. Check the toggle is ON in the dashboard
  2. Check the Bot Token is correct
  3. Check the Signing Secret is correct
  4. Check Event Subscriptions are active in your Slack App
  5. Check Merlin is invited to the channel (/invite @Merlin)
  6. Check the user has a PIN (or a default PIN is set)

The employee has no PIN linked and no default PIN is set. Go to the dashboard and assign a PIN, or set a default PIN.

"Monthly budget reached"

The account has a budget cap configured and it has been reached. Increase the cap under Billing in the dashboard.

Teams channel

Connect Microsoft Teams as an inbound channel for CallMerlin.

Billing

Manage subscription, invoices and minute usage.

On this page

Slack ChannelAvailabilityHow it worksRequirementsSetupStep 1: Create a Slack AppStep 2: Set up Event SubscriptionsStep 3: Configure the dashboardStep 4: Send your first messageUser mappingAssign a PINUnlink a PINDefault PINChannel filterContext and follow-up questionsBillingRate limitsWhat can you ask?LimitationsTroubleshootingMerlin doesn't respond"Link your Slack account to a PIN""Monthly budget reached"