list_block_types

List every block type understood by Card Builder.

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-block-types.md

WHAT IT DOES

What list_block_types does on Ha Nexus Agent

AI agents call list_block_types 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_block_types is rated Low

This tool retrieves metadata about available block types in Home Assistant's Card Builder system. It performs information retrieval only, with no capability to modify, delete, execute operations, or affect system state. The blast radius of misuse is negligible—an agent could only query what block types exist, not modify the home automation system itself.

From the tool's definition Tool name 'list_block_types' with description 'List every block type understood by Card Builder' indicates a query/retrieval operation with no side effects.

Risk signalsBulk/mass operation — affects multiple targets

Attacks that exploit this kind of access

RECOMMENDED RULE

The rule that runs list_block_types 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_block_types, this is the rule to start with:

list_block_types Allowed

list_block_types 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_block_types": {}
  }
}

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_block_types call is checked against it from then on.

FAQ

Questions about list_block_types

What does the list_block_types tool do? +

List every block type understood by Card Builder. 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_block_types? +

Register the Ha Nexus Agent MCP server in PolicyLayer and add a rule for list_block_types: 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_block_types? +

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

Can I rate-limit list_block_types? +

Yes. Add a rate_limit block to the list_block_types 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_block_types completely? +

Set action: deny in the PolicyLayer policy for list_block_types. 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_block_types? +

list_block_types 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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