create_card

Create a new Card Builder card.

SERVERHa Nexus Agent SOURCEfistacho/ha-nexus-agent

Medium RISK CLASS

Category Write

Parameters 00 required

Recommended Rate-limitedsee the rule below

Registry record Grade F, identity unverified Pull the record →

This record as markdown: /tools/fistacho-ha-nexus-agent/create-card.md

WHAT IT DOES

What create_card does on Ha Nexus Agent

AI agents use create_card to create or update resources in Ha Nexus Agent, usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Ha Nexus Agent environment.

RISK

Why create_card is rated Medium

This tool creates a new card in Home Assistant's Card Builder, which is a reversible operation that modifies dashboard configuration. It falls under Write category as it creates data that can be modified or deleted. Severity is low because creating UI cards has minimal blast radius—worst case is visual clutter or need to delete unwanted cards.

From the tool's definition Tool name 'create_card' and description 'Create a new Card Builder card' indicate creation of a UI/dashboard element.

Attacks that exploit this kind of access

RECOMMENDED RULE

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

create_card Rate-limited

create_card stays usable, but capped: an agent stuck in a loop can't make hundreds of changes a minute. Everything else on the server is denied unless you say otherwise.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "create_card": {
      "limits": [
        {
          "counter": "create_card_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

LIMIT 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 create_card call is checked against it from then on.

FAQ

Questions about create_card

What does the create_card tool do? +

Create a new Card Builder card. It is categorised as a Write tool in the Ha Nexus Agent MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on create_card? +

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

create_card is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.

Can I rate-limit create_card? +

Yes. Add a rate_limit block to the create_card 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 create_card completely? +

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

create_card 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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