WORKSPACE MESSAGING / Slack
Slack MCP
Searches workspace conversations and performs Slack actions under the authenticated user’s scopes and workspace policy.
“With the Slack MCP server, your integrated apps can search channels, send messages, and perform other Slack actions through MCP clients.”
01 / THE REASONING
Why this made the selection.
- Adds conversation history and team decisions that issue trackers and knowledge pages may not contain.
- Slack documents per-tool OAuth scopes, workspace approval and the limits on eligible client applications.
- The page names slack_complete_file_upload, so the review can cite operations instead of a vendor slogan.
- Authentication is described as OAuth (or a documented token fallback), which decides what the client must hold.
02 / THE REVIEW RECORD
What we actually inspected.
Source review has boundaries.
A clear record is more useful than a “safe” badge.
Material inspected
- Slack MCP overview: tools, scopes, endpoint and app restrictions.
- Claude and Cursor connection guides: approved client setup and OAuth.
- Sample-app development guide: app registration, scope selection and consent.
- Documentation slack-mcp-server
- Round 2 reread of acquired publisher setup and permission evidence; see immutable wave review.
Our findings
- Private-channel and messaging authority comes from specific OAuth scopes, not merely from adding the endpoint.
- The documented Claude command installs the Slack MCP and Skills plugin, which configures the server and starts OAuth.
- The reviewed page names slack_complete_file_upload and describes it as tool with the file ID to finalize it, optionally sharing the file to a channel with a message.
- The page documents the remote endpoint https://mcp.slack.com/mcp.
- That endpoint is documented with Streamable HTTP, not only as a local process.
- The page describes an OAuth sign-in for the hosted server.
- MCP requests are subject to the same Slack API rate limits and IP-allowlist restrictions as their underlying Web API operations.
Not established by this review
- Workspace installation, OAuth, searches, message sends and admin controls were not executed.
- The server was not installed or initialised.
- No tools/list or tool call was made.
- A source review is not a runtime or security certification.
The review applies to the material and revision named here. A newer upstream release can change its behavior.
03 / PUT IT TO WORK
Connect a server deliberately.
DOCUMENTED COMMAND
claude plugin install slackCopying does not execute this command. It may retrieve a newer version than the reviewed source.
- In Claude Code, install the documented Slack MCP and Skills plugin, then complete workspace OAuth.
- For Claude Desktop add Slack through Connectors; Cursor users should follow Slack’s separate guide.
Before you start
- The chosen supported client and access to a Slack workspace.
- Workspace-admin approval for the integration.
Documented configuration example
Use the client and authentication context described in the setup guidance. Configuration formats vary between hosts.
{
"mcpServers": {
"slack": {
"type": "http",
"url": "https://mcp.slack.com/mcp",
"oauth": {
"clientId": "1601185624273.8899143856786",
"callbackPort": 3118
}
}
}
}04 / FOLLOW THE EVIDENCE
The source trail.
Our notes are separate from the original resource.
Check upstream before adopting a new version.
https://docs.slack.dev/ai/slack-mcp-server/
Supports: upstreamDescription, descriptionSourceUrl, summary, whySelected, bestFor, limitations, transports, review, access
https://docs.slack.dev/ai/slack-mcp-server/connect-to-claude/
Supports: install, compatibility, review
https://docs.slack.dev/ai/slack-mcp-server/connect-to-cursor/
Supports: install, compatibility
https://docs.slack.dev/ai/slack-mcp-server/developing/
Supports: review, access, compatibility, install.prerequisites
- Slack workspace plans ↗Checked
https://slack.com/pricing
Supports: access.cost