Check Your Filesystem's Usage from OpenCode

Let OpenCode inspect mountable.io storage usage through a local MCP server, with your API key in the environment and each tool enabled deliberately.

Your coding agent is about to generate reports into a filesystem that is nearly full. Its next write may be refused. You switch to a dashboard or copy CLI output into the conversation to check how much room remains.

mountable.io is a persistent filesystem for AI agents. Its local MCP server lets OpenCode inspect usage in the conversation, before the job starts. You can ask for current numbers without copying them by hand.

Start with one read-only tool

Use an existing account and filesystem, and create an API key scoped to that filesystem. Load the key into the terminal environment before starting OpenCode. The setup guide shows how to enter it without putting its value in shell history.

Add the server to your project's opencode.json. This is the local-server entry for OpenCode 1.19.4:

"mountable": {
  "type": "local",
  "command": ["npx", "-y", "mountable-cli@0.8.0", "mcp"],
  "enabled": true,
  "environment": { "MOUNTABLE_API_KEY": "{env:MOUNTABLE_API_KEY}" }
}

Put that entry inside mcp. Then set mountable_* to deny and mountable_filesystem_usage to ask under permission, in that order. The full configuration includes both. Other management tools can create resources or revoke sessions, so enable only the calls you want the agent to make.

Run opencode mcp list to check the connection. Then ask OpenCode to call mountable_filesystem_usage with your filesystem ID and show its retained bytes, byte quota, entry count and entry quota. Review and approve the call.

The key's grants and OpenCode's tool permissions work together. A key limits the filesystems the server can access. OpenCode decides which tools the agent may request and when to ask you first. Keep the key in the environment and out of the conversation.

mountable.io usage is paid at the published prices, and your model provider's bill is separate.

Use the same filesystem for the files

To read and write report contents, use the CLI, SDKs or a mount. These reach the same filesystem whose usage you inspect through MCP. OpenCode can also discover the existing mountable.io skill for those workflows.

Follow the OpenCode setup guide for the complete configuration, expected usage fields, skill installation and disconnect steps. This setup is maintained by mountable.io.