AI agents use switch_fan to create or update resources in Jenius MCP Smart Device — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Jenius MCP Smart Device environment.
This tool writes a state change (on/off) to a smart home device (electric fan) via Home Assistant. It is reversible (can be turned back on/off), so it falls under Write rather than Destructive. Misuse could cause discomfort or safety issues (e.g., turning off a fan in a hot environment), warranting medium severity.
From the tool's definition 控制电扇开关的流程 (Control the fan switch process) — toggles a smart fan on or off
Documented attack patterns abuse exactly the kind of access switch_fan gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Jenius MCP Smart Device, and nothing reaches the server without passing your rules. This is the rule we recommend for switch_fan:
{
"version": "1",
"default": "deny",
"tools": {
"switch_fan": {
"limits": [
{
"counter": "switch_fan_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}switch_fan 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.
Free to start. No card required.
控制电扇开关的流程。请根据用户的需求抽取参数，控制设备。. It is categorised as a Write tool in the Jenius MCP Smart Device MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Jenius MCP Smart Device MCP server in PolicyLayer and add a rule for switch_fan: 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 Jenius MCP Smart Device. Nothing to install.
switch_fan is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.
Yes. Add a rate_limit block to the switch_fan 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.
Set action: deny in the PolicyLayer policy for switch_fan. 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.
switch_fan is provided by the Jenius MCP Smart Device MCP server (jenius-group/jenius-mcp-smart-device). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Jenius MCP Smart Device, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
Free to start. No card required.
12 Jenius MCP Smart Device tools catalogued and risk-classified — across an index of 43,000+ MCP servers.