Slack MCP missing_scope

Slack MCP missing_scope

TL;DR: Add the missing scope to the Slack app OAuth scopes and reinstall the app in the workspace. The error names the scope you need; copy it exactly. Restart the MCP client after reinstalling so the new token is issued.

The error

missing_scope

Fix it

1. Read the error; it names the required scope. Expected: You have the scope string.

2. In the Slack app settings, add that scope under OAuth and Permissions. Expected: The scope is listed.

3. Reinstall the app to the workspace to issue a new token. Expected: Slack confirms the install.

4. Update the token in the MCP config if it changed, then restart the client. Expected: The tool call succeeds.

When this applies

A specific Slack MCP tool fails with missing_scope while the token and channel membership are fine.

When this does NOT apply

notallowedtoken_type is a token-type problem, not a scope. If the app was never installed, install it first.

Tool compatibility

korotovsky/slack-mcp-server, recent versions

Also seen as

• Slack MCP scope error
• Slack bot missing scope reinstall
• slack MCP needs scope reinstalled

Why it happens

Slack issues tokens bound to the app's scope list at install time. Adding a scope later does not update existing tokens; only a reinstall mints a token with the new scope.

Edge cases

• Workspace admins may need to approve the reinstall.
• Bot and user tokens have separate scope lists; fix the right one.
• Test with the Slack API tester to confirm the scope before reinstalling.

Documented in korotovsky/slack-mcp-server issues: missing_scope is fixed by adding the scope and reinstalling the app. https://github.com/korotovsky/slack-mcp-server