AI agents call get_ui_element_value to retrieve information from Mac without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool only reads/queries the current state of macOS UI elements (text content, checkbox state, etc.). It has no side effects, makes no modifications, executes no commands, and cannot delete or move money. It is a pure read operation with minimal blast radius if misused—at worst, an agent could learn UI element values to inform other actions, but the tool itself is passive observation.
From the tool's definition Tool name 'get_ui_element_value' and description 'Gets the value of a UI element (text field content, checkbox state, etc.)' indicate retrieval of UI state without modification or execution of code.
Attacks that exploit this kind of access
Gets the value of a UI element (text field content, checkbox state, etc.). It is categorised as a Read tool in the Mac MCP Server, which means it retrieves data without modifying state.
Register the Mac MCP server in PolicyLayer and add a rule for get_ui_element_value: 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 Mac. Nothing to install.
get_ui_element_value 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 get_ui_element_value 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 get_ui_element_value. 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.
get_ui_element_value is provided by the Mac MCP server (laststance/mac-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Every MCP server has a record like this.
Type a name, get the same breakdown: verified identity, auth posture, risk grade, capabilities, recommended policy.
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