AI agents call list_windows to retrieve information from Computer Control MCP without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
The tool queries and retrieves a list of open windows—purely informational with no side effects. This is a straightforward read operation. Severity is low because listing windows provides system metadata that does not expose sensitive user data at scale and does not grant further capabilities on its own.
From the tool's definition Tool name is 'list_windows' with description 'List all open windows on the system.' This retrieves information about system state without modifying or executing anything.
Documented attack patterns abuse exactly the kind of access list_windows gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Computer Control MCP, and nothing reaches the server without passing your rules. This is the rule we recommend for list_windows:
{
"version": "1",
"default": "deny",
"tools": {
"list_windows": {}
}
}list_windows is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
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List all open windows on the system. It is categorised as a Read tool in the Computer Control MCP MCP Server, which means it retrieves data without modifying state.
Register the Computer Control MCP server in PolicyLayer and add a rule for list_windows: 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 Computer Control MCP. Nothing to install.
list_windows is a Read tool with low risk. Read-only tools are generally safe to allow by default.
Yes. Add a rate_limit block to the list_windows 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 list_windows. 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.
list_windows is provided by the Computer Control MCP server (ab498/computer-control-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 15 Computer Control MCP tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
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15 Computer Control MCP tools catalogued and risk-classified — across an index of 42,500+ MCP servers.