Slack MCP

1. Prerequisites

Before using the Slack MCP node you need:

• A Slack account: sign up at https://slack.com/

• A Slack workspace

• An OAuth client app: generated inside your Slack workspace. This gives you a Client ID and Client Secret.

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2. Setting Up Slack Credentials

2.1 Create a new app in Slack

1. Go to https://api.slack.com/apps/new

2. Create a new app, either via manifest or from scratch.

1. After an app is created, grab the Client ID and Client Secret.

2.2 Add Credentials in Flowise

1. In Flowise, navigate to Credentials from the sidebar.

2. Click Add Credential and search for Slack User Token OAuth2.

3. Fill in the following fields:

Field	Description	Example
Client ID	The OAuth Client ID from Slack	wBSGhxxxx
Client Secret	The OAuth Client Secret (stored securely)	••••••••
Scopes	(Optional) Space-separated scopes.	search:read.public search:read.private search:read.mpim search:read.im search:read.files search:read.users groups:history mpim:history im:history channels:history chat:write canvases:read canvases:write users:read users:read.email

1. Copy OAuth Redirect URL, then click Save.

Tip: For production environments, use the narrowest scopes you need. See available scopes.

2.3 Add Redirect URL to Slack App

1. From the left side nav bar, select OAuth & Permissions:

1. Scroll down and you will see Redirect URLs section. Add the copied redirect URL from previous step. Then click Save URLs.

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3. Adding Slack MCP

1. Drag and drop an Agent node.

2. Add a new Slack MCP tool.

1. Select preconfigured credential, and click the edit button. Click Authenticate.

1. A slack pop-up window will appear, review the permissions and click Allow.

1. After authenticated, click the refresh button to load the available actions.

1. Select the actions. Tip: Select only the actions your agent needs. Fewer tools help the LLM make better decisions and reduce token usage.

1. Voila! You can start chatting with the Agent and see how its calling Slack MCP tools.