Moves the mouse from (start_x, start_y) to (end_x, end_y) while holding a number of keys.
AI agents invoke move_mouse_with_keys_held to trigger actions in Vnc. 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 performs a coordinated mouse movement with simultaneous key-holding on a remote VNC desktop, enabling drag-and-drop operations, text selection, or other complex UI interactions. It is an active desktop control action that triggers external operations whose effects depend on arguments. It falls under Execute as it drives real UI automation with potentially wide-ranging side effects depending on context (e.g.
From the tool's definition Moves the mouse from (start_x, start_y) to (end_x, end_y) while holding a number of keys
Documented attack patterns abuse exactly the kind of access move_mouse_with_keys_held gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Vnc, and nothing reaches the server without passing your rules. This is the rule we recommend for move_mouse_with_keys_held:
{
"version": "1",
"default": "deny",
"tools": {
"move_mouse_with_keys_held": {
"limits": [
{
"counter": "move_mouse_with_keys_held_rate",
"window": "minute",
"max": 10,
"scope": "grant"
}
]
}
}
}move_mouse_with_keys_held 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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Moves the mouse from (start_x, start_y) to (end_x, end_y) while holding a number of keys. It is categorised as a Execute tool in the Vnc MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.
Register the Vnc MCP server in PolicyLayer and add a rule for move_mouse_with_keys_held: 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 Vnc. Nothing to install.
move_mouse_with_keys_held 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 move_mouse_with_keys_held 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 move_mouse_with_keys_held. 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.
move_mouse_with_keys_held is provided by the Vnc MCP server (regulad/vnc-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Vnc, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
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20 Vnc tools catalogued and risk-classified — across an index of 43,000+ MCP servers.