app_categories

List all app categories available in the catalog.

SERVERTruenas SOURCEspranab/truenas-mcp

Low RISK CLASS

Category Read

Parameters 00 required

Recommended Allowedsee the rule below

Registry record Grade F, identity unverified Pull the record →

This record as markdown: /tools/spranab-truenas-mcp/app-categories.md

WHAT IT DOES

What app_categories does on Truenas

AI agents call app_categories to retrieve information from Truenas without modifying anything. It is typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.

RISK

Why app_categories is rated Low

This tool retrieves and lists application categories from a catalog. It is a read-only query operation that does not modify, create, delete, or execute any code. The action is informational only, making it low severity with minimal blast radius if misused by an agent.

From the tool's definition Tool name 'app_categories' combined with description 'List all app categories available in the catalog' indicates a retrieval operation with no side effects.

Attacks that exploit this kind of access

RECOMMENDED RULE

The rule that runs app_categories safely

PolicyLayer is an MCP gateway: it sits between your AI agents and Truenas, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For app_categories, this is the rule to start with:

app_categories Allowed

app_categories is read-only, so it stays allowed. Everything else on the server is denied unless you say otherwise.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "app_categories": {}
  }
}

ALLOW ONLY THIS TOOL → Instant setup, no code required.

The button opens the PolicyLayer dashboard: create your workspace, connect Truenas, apply this rule, and every app_categories call is checked against it from then on.

FAQ

Questions about app_categories

What does the app_categories tool do? +

List all app categories available in the catalog. It is categorised as a Read tool in the Truenas MCP Server, which means it retrieves data without modifying state.

How do I enforce a policy on app_categories? +

Register the Truenas MCP server in PolicyLayer and add a rule for app_categories: allow, deny, rate-limit, or require approval. Point your MCP client at the PolicyLayer proxy URL and the rule is enforced on every call, before it reaches Truenas. Nothing to install.

What risk level is app_categories? +

app_categories is a Read tool with low risk. Read-only tools are generally safe to allow by default.

Can I rate-limit app_categories? +

Yes. Add a rate_limit block to the app_categories rule in your PolicyLayer policy. For example, setting max: 10 and window: 60 limits the tool to 10 calls per minute. Rate limits are tracked per agent session and reset automatically.

How do I block app_categories completely? +

Set action: deny in the PolicyLayer policy for app_categories. The AI agent will receive a policy violation error and cannot call the tool. You can also include a reason field to explain why the tool is blocked.

What MCP server provides app_categories? +

app_categories is provided by the Truenas MCP server (spranab/truenas-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

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