AI agents invoke turn_on_group to trigger actions in Philips Hue MCP Server. 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.
This tool executes an external operation affecting physical devices (Philips Hue lights). It's not a simple data write; it triggers real-world state changes in smart home hardware. Severity is low because the blast radius of turning on lights is minimal and easily reversible.
From the tool's definition "Turn on all lights in a specific group" — triggers an external operation (controlling physical smart lighting hardware)
Documented attack patterns abuse exactly the kind of access turn_on_group gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Philips Hue MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for turn_on_group:
{
"version": "1",
"default": "deny",
"tools": {
"turn_on_group": {
"limits": [
{
"counter": "turn_on_group_rate",
"window": "minute",
"max": 10,
"scope": "grant"
}
]
}
}
}turn_on_group 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.
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Turn on all lights in a specific group. It is categorised as a Execute tool in the Philips Hue MCP Server MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.
Register the Philips Hue MCP Server MCP server in PolicyLayer and add a rule for turn_on_group: 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 Philips Hue MCP Server. Nothing to install.
turn_on_group is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.
Yes. Add a rate_limit block to the turn_on_group 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 turn_on_group. 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.
turn_on_group is provided by the Philips Hue MCP Server MCP server (thomasrohde/hue-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Philips Hue MCP Server, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
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23 Philips Hue MCP Server tools catalogued and risk-classified — across an index of 43,000+ MCP servers.