TrueNAS MCP

Start App

start_app

Starts an installed TrueNAS app by name so you can run it after installation or a stop; startup can take several seconds.

Instructions

Start an installed app. Long-running (may take seconds).

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": {
      "app_name": "<app_name>"
    },
    "name": "start_app"
  }
}

Input Schema

Name	Required	Description	Default
`app_name`	Yes

Output Schema

Name	Required	Description	Default
`result`	Yes

Schema Changelog

Changes observed during successful MCP inspections.

First observedv1.0.0Oct 23, 2026

TDQS

B3.1/5.0

Behavior3/5

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

No annotations exist, so the description carries the full load; it does disclose that the operation is long-running and may take seconds, which is genuinely useful for timeout/retry decisions. It says nothing about idempotency, behavior when the app is already running, permission requirements, or failure modes.

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?

Two short sentences, zero filler, with the core action front-loaded and the latency caveat immediately after. Every sentence earns its place.

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?

An output schema exists, so return values need not be explained, and the latency warning covers the main operational surprise. Still missing for a mutation-style lifecycle tool with no annotations: idempotency, already-running behavior, and how to resolve app_name.

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

Parameters2/5

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

Schema description coverage is 0% for the single parameter app_name, so the schema provides only a bare string type. The description's phrase "installed app" weakly implies the value must be the name of an already-installed app, but it gives no format, matching rules, or discovery path to compensate for the coverage gap.

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?

"Start an installed app" names a specific verb and resource, and the qualifier "installed" separates it from install_app and search_app_catalog. An agent can tell it apart from stop_app/update_app without reading further, though the description does not explicitly call out those siblings.

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?

There is no explicit when-to-use guidance, no indication of how to obtain a valid app_name (e.g., via list_apps), and no note on when to prefer update_app/install_app instead. The word "installed" implies a precondition but the agent must infer it.

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