update_card

Update an existing card. Only the provided fields are changed.

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/update-card.md

WHAT IT DOES

What update_card does on Ha Nexus Agent

AI agents use update_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 update_card is rated Medium

This tool modifies dashboard/card configuration in a Home Assistant system. It is reversible (the update can be undone by updating again with different values), so it falls into the Write category rather than Destructive.

From the tool's definition Tool description states 'Update an existing card. Only the provided fields are changed.' The verb 'update' indicates modification of existing data.

Attacks that exploit this kind of access

RECOMMENDED RULE

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

update_card Rate-limited

update_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": {
    "update_card": {
      "limits": [
        {
          "counter": "update_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 update_card call is checked against it from then on.

FAQ

Questions about update_card

What does the update_card tool do? +

Update an existing card. Only the provided fields are changed. 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 update_card? +

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

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

Can I rate-limit update_card? +

Yes. Add a rate_limit block to the update_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 update_card completely? +

Set action: deny in the PolicyLayer policy for update_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 update_card? +

update_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.

KEEP EXPLORING

More on Ha Nexus Agent, and thousands of servers like it.

This server

All 276 Ha Nexus Agent tools →

Across the catalogue

aroflo_create_or_update_record on AroFlo MCP →team_manager_update_budget on Team Manager MCP → The MCP Attack Database →

Guides

Govern customer-ops agents →Argument validation →Scoped token →