list_categories

List categories for a scope (e.g. 'automation') via WS config/category_registry/list.

SERVERHa Nexus Agent SOURCEfistacho/ha-nexus-agent

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/fistacho-ha-nexus-agent/list-categories.md

WHAT IT DOES

What list_categories does on Ha Nexus Agent

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

RISK

Why list_categories is rated Low

This tool retrieves or queries data about categories within a specified scope (e.g., automation) in Home Assistant. It has no side effects, does not execute commands, does not modify data, and does not delete anything. It is a straightforward data retrieval operation, making it a Read category tool with low severity.

From the tool's definition Tool description states 'List categories' which is a retrieval operation. The WS endpoint `config/category_registry/list` is a read-only query that fetches category metadata without modification or side effects.

Attacks that exploit this kind of access

RECOMMENDED RULE

The rule that runs list_categories safely

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

list_categories Allowed

list_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": {
    "list_categories": {}
  }
}

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

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

FAQ

Questions about list_categories

What does the list_categories tool do? +

List categories for a scope (e.g. 'automation') via WS config/category_registry/list. It is categorised as a Read tool in the Ha Nexus Agent MCP Server, which means it retrieves data without modifying state.

How do I enforce a policy on list_categories? +

Register the Ha Nexus Agent MCP server in PolicyLayer and add a rule for list_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 Ha Nexus Agent. Nothing to install.

What risk level is list_categories? +

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

Can I rate-limit list_categories? +

Yes. Add a rate_limit block to the list_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 list_categories completely? +

Set action: deny in the PolicyLayer policy for list_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 list_categories? +

list_categories is provided by the Ha Nexus Agent MCP server (fistacho/ha-nexus-agent). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

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