AI agents call scan_menu_bar to retrieve information from ScreenHand without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool retrieves or queries information about an application's menu bar structure without executing commands, modifying data, or triggering side effects. It is a read-only inspection capability similar to 'ax_tree' (another sibling tool that reads UI structure).
From the tool's definition Tool name 'scan_menu_bar' and description 'Scan an app' indicate retrieval of menu bar information or application state without modification.
Documented attack patterns abuse exactly the kind of access scan_menu_bar gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and ScreenHand, and nothing reaches the server without passing your rules. This is the rule we recommend for scan_menu_bar:
{
"version": "1",
"default": "deny",
"tools": {
"scan_menu_bar": {}
}
}scan_menu_bar is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
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Scan an app. It is categorised as a Read tool in the ScreenHand MCP Server, which means it retrieves data without modifying state.
Register the ScreenHand MCP server in PolicyLayer and add a rule for scan_menu_bar: 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 ScreenHand. Nothing to install.
scan_menu_bar 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 scan_menu_bar 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 scan_menu_bar. 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.
scan_menu_bar is provided by the ScreenHand MCP server (manushi4/screenhand). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from ScreenHand, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
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89 ScreenHand tools catalogued and risk-classified — across an index of 43,000+ MCP servers.