TrueNAS MCP

Create Snapshot

create_snapshot

Create a ZFS snapshot for a specified dataset, with an optional name and dry-run preview before committing changes.

Instructions

Create a ZFS snapshot.

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": {
      "dataset": "<dataset>"
    },
    "name": "create_snapshot"
  }
}

Input Schema

Name	Required	Description
`name`	No	Optional snapshot name (defaults to auto timestamp).
`dataset`	Yes	Dataset to snapshot, e.g. "tank/data".
`dry_run`	No	Preview only (default True); set False to create.

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?

No annotations are provided, so the description carries the full behavioral burden. It says 'Create' but does not disclose that dry_run defaults to true (preview only), nor does it explain side effects, permissions, or what happens if the snapshot name already exists.

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

Conciseness4/5

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

The description is a single front-loaded sentence with zero waste. It is concise, though its brevity leaves important behavioral context unstated.

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

Completeness3/5

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

The input schema fully documents the parameters and an output schema exists, so the description does not need to repeat parameter details. However, for a mutating operation with no annotations, it omits important context such as the dry_run default and the preview-versus-create distinction.

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 schema already documents all three parameters, including the dry_run default and optional name behavior. The description adds no parameter semantics beyond the schema, which is the expected baseline when the schema is fully described.

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 description states a specific verb and resource: 'Create a ZFS snapshot.' It is clear what the tool does, but it does not distinguish itself from siblings such as delete_snapshot or list_snapshots.

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?

The description gives no guidance on when to use this tool versus alternatives, nor does it mention prerequisites, such as whether the dataset must already exist or how it relates to delete_snapshot/list_snapshots.

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