AI agents invoke select_option to trigger actions in Macos Control. 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 UI control action (selecting a dropdown option) on macOS, which constitutes an Execute-level operation as it triggers external UI interactions whose effects depend on arguments. While it's a relatively contained action, it could change application settings or trigger further operations depending on which dropdown and option are selected.
From the tool's definition Select a dropdown option by the dropdown — triggers a UI interaction (selecting from a dropdown) on the macOS environment, which is a browser/UI action that can affect application state
Documented attack patterns abuse exactly the kind of access select_option gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Macos Control, and nothing reaches the server without passing your rules. This is the rule we recommend for select_option:
{
"version": "1",
"default": "deny",
"tools": {
"select_option": {
"limits": [
{
"counter": "select_option_rate",
"window": "minute",
"max": 10,
"scope": "grant"
}
]
}
}
}select_option 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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Select a dropdown option by the dropdown. It is categorised as a Execute tool in the Macos Control MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.
Register the Macos Control MCP server in PolicyLayer and add a rule for select_option: 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 Macos Control. Nothing to install.
select_option 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 select_option 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 select_option. 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.
select_option is provided by the Macos Control MCP server (peterhdd/macos-control-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Macos Control, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
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22 Macos Control tools catalogued and risk-classified — across an index of 43,000+ MCP servers.