How to connect Slack to Claude Code

1. 1. Enable Slack in Metorial

   In your Metorial portal, enable the Slack MCP server and sign in with the account that owns the data. Access stays governed by your team policies.

2. 2. Add the server over HTTP

   Add --scope user to use it in every project.

   Copy

   claude mcp add --transport http metorial <your-magic-mcp-url>

3. 3. Sign in

   Run /mcp, select Metorial and sign in to load Slack tools.

• Manage Pins: Pin or unpin messages in a Slack channel, or list all pinned items.
• Manage Channel Members: Invite users to or remove users from a Slack channel.
• Get User Info: Look up a Slack user's profile and status.
• Get Team Info: Retrieve information about the Slack workspace (team), including its name, domain, email domain, and icon.
• Manage User Groups: Create, update, enable, disable, or list user groups (also known as @mention handle groups) in Slack.
• Send Message: Send a message to a Slack channel, group DM, or direct message conversation.
• Schedule Message: Schedule a message to be sent to a Slack channel at a future time.
• Manage Reminders: Create, complete, delete, or list Slack reminders.
• Manage Channel: Create, update, archive, unarchive, or configure a Slack channel.
• Get Conversation History: Retrieve message history from a Slack channel, DM, or group DM.
• Manage Bookmarks: Add, edit, remove, or list bookmarks (saved links) in a Slack channel.
• Manage Files: Upload, list, get info about, or delete files in Slack.
• Update Message: Update or delete an existing Slack message.
• Manage Reactions: Add, remove, or list emoji reactions on a Slack message.
• Search Messages: Search messages across a Slack workspace with Real-time Search using keywords or a natural-language question.
• And 33 more on the Slack MCP server page.

• Slack tools appear as mcp__metorial__<tool>. Use that name in permission rules to allow or deny a tool.
• Run /mcp to see whether Metorial is connected and to sign in again.
• Claude Code warns when a tool result passes 10,000 tokens and caps it at 25,000 by default. Raise the cap with MAX_MCP_OUTPUT_TOKENS.
• Pre-approve trusted Slack tools with allow rules in your settings so Claude Code stops asking each time.

claude mcp list shows "Needs authentication"

Run /mcp, select Metorial, and sign in. If sign-in keeps failing, choose Clear authentication in the same menu and sign in again.

A teammate sees "Pending approval"

Servers shared through a project .mcp.json need approval. Run claude in the project and approve Metorial when asked.

Large tool results are cut off

Claude Code limits MCP tool output to 25,000 tokens by default. Raise it with the MAX_MCP_OUTPUT_TOKENS environment variable.

Based on the Claude Code MCP documentation.