Health

Tool Name: disks/health

Returns a drive's SMART data as smartctl's JSON (wraps smartctl -j -a; the smartmontools package must be installed or the call fails saying so). Read-only, but normally needs root: use privileged: true (needs a grant), since without it smartctl usually cannot open the device. device is a bare kernel name such as sda or nvme0n1, never a path; find names with disks/list. The reply is smartctl's JSON verbatim (keys such as smart_status, temperature, ata_smart_attributes or nvme_smart_health_information_log vary by drive type); a non-zero smartctl exit is not an error when it printed JSON, and virtual disks report SMART as unsupported. For I/O counters use disks/performance.

Arguments

Argument	Type	Required	Description
`device`	string	yes	Bare kernel device name such as 'sda' or 'nvme0n1' (never a path)
`privileged`	boolean	no	Run as root - required to read SMART data. Needs a grant for this tool in mcp-sudo.yaml

Example

Every example below shows the equivalent linuxctl command and the raw MCP JSON-RPC call it resolves to. The raw call always follows the same two-step pattern (see MCP API overview for the full explanation): open an SSE stream to get a one-time POST endpoint, then POST the JSON-RPC request there - the result streams back on the SSE connection.

linuxctl

linuxctl get disks health vda

Output (Ubuntu 24.04 VPS, first 25 lines):

{
  "json_format_version": [
    1,
    0
  ],
  "smartctl": {
    "version": [
      7,
      4
    ],
    "pre_release": false,
    "svn_revision": "5530",
    "platform_info": "x86_64-linux-6.8.0-142-generic",
    "build_info": "(local build)",
    "argv": [
      "smartctl",
      "-j",
      "-a",
      "/dev/vda"
    ],
    "messages": [
      {
        "string": "/dev/vda: Unable to detect device type",
        "severity": "error"
      }
...

curl (raw MCP JSON-RPC)

# 1. Open the SSE stream (in the background) and capture the one-time POST endpoint
curl -N -s --cacert mcpd.crt -H "Authorization: Bearer $MCP_TOKEN" https://localhost:9091/sse &
# server sends: event: endpoint / data: /message?session_id=...

# 2. POST the tools/call request to that endpoint
curl -s --cacert mcpd.crt -X POST "https://localhost:9091/message?session_id=<from step 1>" \
  -H "Authorization: Bearer $MCP_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{"jsonrpc": "2.0", "id": "1", "method": "tools/call", "params": {"name": "disks/health", "arguments": {"device": "vda"}}}'

# 3. The result arrives on the SSE stream opened in step 1

Response:

{
  "jsonrpc": "2.0",
  "id": "1",
  "result": {
    "content": [
      {
        "type": "text",
        "text": "{\n  \"json_format_version\": [\n    1,\n    0\n  ],\n  \"smartctl\": {\n    \"version\": [\n      7,\n      4\n    ],\n    \"pre_release\": false,\n    \"svn_revision\": \"5530\",\n    \"platform_info\": \"x86_64-linux-6.8.0-142-generic\",\n    \"build_info\": \"(local build)\",\n    \"argv\": [\n      \"smartctl\",\n      \"-j\",\n      \"-a\",\n      \"/dev/vda\"\n    ],\n    \"messages\": [\n      {\n        \"string\": \"/dev/vda: Unable to detect device type\",\n        \"severity\": \"error\"\n      }\n..."
      }
    ]
  }
}

Arguments​

Example​

Arguments

Example