Slack MCP Server

What the code does

We read the source, 19 h ago · rules 3dff92dd89df

A value the model can set ends up inside a file or shell call. That is not a flaw by itself — for a terminal server it is the job — but it is where things go wrong when it is not.

          fs.writeFileSync(outFd, pdfBuffer);

What this server is able to do. For an MCP server this is often the job itself — a terminal server runs commands because that is what it is for. Listed so you know what you are plugging in, not as an accusation.

  const fullPath = path.join(stagingDir, filename);

    const child = spawn(process.execPath, [script], {

  if (isUnder(resolvedAbs, sshDir)) return { hit: true, reason: '~/.ssh/** is sensitive' };

  <script src="https://appsforoffice.microsoft.com/lib/1.1/hosted/office.js"></script>

    const entries = fs.readdirSync(workspacePath, { withFileTypes: true });

Is this your server and something here is wrong? Tell us — corrections are free and do not require a plan.

Connect this server

This server runs on your own machine — install it with the package manager and the client starts it for you. Package name taken from the official registry entry.

claude mcp add mcp-server-slack -- npx -y @mindstone/mcp-server-slack

{
  "mcpServers": {
    "mcp-server-slack": {
      "args": [
        "-y",
        "@mindstone/mcp-server-slack"
      ],
      "command": "npx"
    }
  }
}

[mcp_servers.mcp-server-slack]
command = "npx"
args = ["-y", "@mindstone/mcp-server-slack"]

{
  "mcpServers": {
    "mcp-server-slack": {
      "args": [
        "-y",
        "@mindstone/mcp-server-slack"
      ],
      "command": "npx"
    }
  }
}

{
  "mcpServers": {
    "mcp-server-slack": {
      "args": [
        "-y",
        "@mindstone/mcp-server-slack"
      ],
      "command": "npx"
    }
  }
}

This one needs environment variables set before it will start: SLACK_CONFIG_PATH (Path to the host-managed Slack config directory), SLACK_TEAM_ID (Slack workspace team ID (one process per workspace)), SLACK_CLIENT_ID (Slack OAuth Connected App client ID. Only required to refresh a rotating token; saved non-rotating tokens authorize the Slack API without it.), SLACK_CLIENT_SECRET (Slack OAuth Connected App client secret. Only required to refresh a rotating token; saved non-rotating tokens authorize the Slack API without it.), SLACK_DISABLE_REFRESH (Set to 1 to disable token refresh on this surface (cloud surface)), SLACK_REQUEST_TIMEOUT_MS (Override the upstream timeout (max 300000ms = 5 min)), SLACK_MAX_RETRIES (WebClient retries on transient failures (0-20). Lower this on cloud to avoid stacking long retry budgets into multi-minute hangs.), MCP_WORKSPACE_PATH (Workspace directory upload_slack_file reads are constrained to (defaults to the system temp dir when unset)). The author declared them in the registry entry; get the values from the project itself.