start_addon

Start an installed add-on.

SERVERHa Nexus Agent SOURCEfistacho/ha-nexus-agent

High RISK CLASS

Category Execute

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/start-addon.md

WHAT IT DOES

What start_addon does on Ha Nexus Agent

AI agents invoke start_addon to trigger actions in Ha Nexus Agent. What it does depends on the arguments the agent supplies, and its effects often reach beyond the immediate call: builds kicked off, notifications sent, workflows started.

RISK

Why start_addon is rated High

This tool executes code by starting a third-party add-on service. While the add-on itself is pre-installed (not user-provided code), the tool triggers autonomous execution of that add-on. The blast radius is high: a malicious add-on or misconfigured legitimate add-on could compromise the smart home, access sensitive data, or cause system instability.

From the tool's definition Tool name 'start_addon' and description 'Start an installed add-on' indicate execution of external operations.

Attacks that exploit this kind of access

RECOMMENDED RULE

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

start_addon Rate-limited

start_addon stays usable, but rate-capped: a runaway agent can't fire it dozens of times a minute. Everything else on the server is denied unless you say otherwise.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "start_addon": {
      "limits": [
        {
          "counter": "start_addon_rate",
          "window": "minute",
          "max": 10,
          "scope": "grant"
        }
      ]
    }
  }
}

RATE-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 start_addon call is checked against it from then on.

FAQ

Questions about start_addon

What does the start_addon tool do? +

Start an installed add-on. It is categorised as a Execute tool in the Ha Nexus Agent MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on start_addon? +

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

start_addon is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.

Can I rate-limit start_addon? +

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

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

start_addon 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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