TrueNAS MCP

Run Scrub

run_scrub

Starts a ZFS scrub on a TrueNAS pool to detect and repair data errors. Use dry_run to preview the operation before running it.

Instructions

Run a ZFS scrub on a pool.

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "pool_name": "<pool_name>"
    },
    "name": "run_scrub"
  }
}

Input Schema

Name	Required	Description	Default
`dry_run`	No	Preview only (default True); set False to run.
`pool_name`	Yes	Pool name, e.g. "tank".

Output Schema

Name	Required	Description	Default
`result`	Yes

Schema Changelog

Changes observed during successful MCP inspections.

First observedv1.0.0Oct 23, 2026

TDQS

C2.9/5.0

Behavior2/5

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

With no annotations, the description carries the full behavioral burden and does not meet it: it says nothing about the operation being long-running/async, I/O-intensive, whether it returns a job handle, or whether it is interruptible. Most importantly, the dry_run default of true means the tool is a no-op preview unless explicitly overridden, and the description never warns of this trap.

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

Conciseness3/5

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

The single front-loaded sentence is free of waste, but it is undersized rather than appropriately sized for a mutation tool with a default-dry-run gotcha. Conciseness here shades into under-specification.

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?

An output schema exists, so return values need not be described, and the input schema fully documents both parameters. What remains missing is behavioral context for a long-running write operation with no annotations to cover it, but the structured data fills most of the gap.

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 both pool_name and the dry_run default/meaning are already documented in structured fields. The description adds no semantics beyond the schema, which is the baseline 3 for a fully-documented two-parameter schema.

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

Purpose4/5

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

The sentence names a concrete verb (run) and resource (ZFS scrub on a pool), which is unambiguous and implicitly distinct from the read-only get_scrub_status sibling. It stops short of explicitly contrasting with that sibling or noting the async/long-running nature.

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

Usage Guidelines2/5

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

No guidance on when to run a scrub versus checking get_scrub_status first, whether a scrub can be run while one is already active, or what pool state is required. The only usage-relevant fact (that dry_run defaults to true, so nothing happens unless it is set false) lives in the schema, not the description.

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