Windsurf / Cascade: MCP setup

Connect Windsurf / Cascade to mountable.io to list filesystems, inspect usage and manage mount sessions through MCP.

The mountable.io MCP server runs locally over stdio. Install Node.js with npx available to the editor, then create an API key with access only to the filesystems you need.

Add the server

Open the MCP configuration from Cascade’s Actions menu, then choose Open MCP config file. Edit the file your installed version opens. Older Windsurf versions use ~/.codeium/windsurf/mcp_config.json. The current Devin Desktop documentation uses ~/.config/devin/mcp_config.json on macOS/Linux for legacy Cascade.

Merge this mountable entry into the existing mcpServers object rather than replacing other servers:

{
  "mcpServers": {
    "mountable": {
      "command": "npx",
      "args": ["-y", "mountable-cli@0.8.0", "mcp"],
      "env": { "MOUNTABLE_API_KEY": "REPLACE_WITH_YOUR_KEY" }
    }
  }
}

Replace REPLACE_WITH_YOUR_KEY in your private local configuration. Never paste the key into a chat, commit it, or pass it as a command argument. If npx is not on the editor’s PATH, use its absolute path.

Check the connection

Save the file, then enable mountable in Cascade’s MCP list. Toggle it off and on if the tools do not appear. This configuration is for Cascade; the Devin Local agent is the default for new tabs and uses the separate Devin CLI configuration.

Ask the agent to call list_filesystems. The result contains the filesystems your key can access; an empty list is valid. Review the call before approving it. An authentication error means you should check the key and its grants, then restart the server.

The MCP tools manage filesystems, usage, mount sessions and webhooks. To read or write file contents, use a mount or the Python/TypeScript SDKs. Mounting remains a separate local command; wait for its mounted event before using the directory.

See the ten MCP tools, permissions, billing and Windsurf / Cascade’s configuration guide.