TrueNAS MCP

List Disks

list_disks

Retrieve disks and their health details—model, serial number, size, and SMART status—optionally filtered by serial to check drive condition.

Instructions

List disks and their health fields (model, serial, size, SMART status).

Tool call template

This tool declares no required parameters. Add optional parameters from the input schema as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {},
    "name": "list_disks"
  }
}

Input Schema

Name	Required	Description	Default
`serial`	No	Restrict to one disk by serial number (optional).

Output Schema

Name	Required	Description	Default
`result`	Yes

Schema Changelog

Changes observed during successful MCP inspections.

First observedv1.0.0Oct 23, 2026

TDQS

A3.8/5.0

Behavior3/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

No annotations are provided, so the description carries the behavioral burden. 'List' implies a read-only operation and the SMART/health fields add useful context, but it does not disclose permissions, whether all disks are returned, or pagination/rate-limit behavior; the output schema covers return shape.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

A single front-loaded sentence with no wasted words. It efficiently states the resource and the useful fields returned.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a simple one-parameter read-only list tool with an output schema, the description covers what is listed and highlights key fields. It omits explicit scope, permissions, and pagination notes, but the output schema handles return-value details.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so the single optional serial parameter is already fully documented as a filter. The description does not add filtering details beyond the schema, but with complete schema coverage the baseline score of 3 is appropriate.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

States the specific verb and resource ('List disks') and enumerates the health fields returned (model, serial, size, SMART status). This clearly distinguishes it from sibling list tools such as list_snapshots, list_shares, and list_alerts.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines3/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The listing intent is clear, but there is no explicit guidance on when to use this versus siblings like system_info or list_pools. The optional serial restriction is only visible in the schema, so usage is implied rather than spelled out.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.