AI agents invoke nanokvm_scroll to trigger actions in NanoKVM 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 emulates mouse wheel input on a remote machine at the BIOS/OS level. While scrolling alone has limited blast radius, it is an active hardware emulation action (not a passive read) that triggers external operations on a remote system. In the context of BIOS-level KVM control, even a scroll action could navigate menus or change settings.
From the tool's definition Scroll the mouse wheel — triggers a physical mouse wheel scroll action on a remotely controlled machine via KVM hardware emulation
Documented attack patterns abuse exactly the kind of access nanokvm_scroll gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and NanoKVM MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for nanokvm_scroll:
{
"version": "1",
"default": "deny",
"tools": {
"nanokvm_scroll": {
"limits": [
{
"counter": "nanokvm_scroll_rate",
"window": "minute",
"max": 10,
"scope": "grant"
}
]
}
}
}nanokvm_scroll 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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Scroll the mouse wheel. It is categorised as a Execute tool in the NanoKVM MCP Server MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.
Register the NanoKVM MCP Server MCP server in PolicyLayer and add a rule for nanokvm_scroll: 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 NanoKVM MCP Server. Nothing to install.
nanokvm_scroll 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 nanokvm_scroll 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 nanokvm_scroll. 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.
nanokvm_scroll is provided by the NanoKVM MCP Server MCP server (scgreenhalgh/nanokvm-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from NanoKVM 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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19 NanoKVM MCP Server tools catalogued and risk-classified — across an index of 43,000+ MCP servers.