AI agents call list-mailboxes to retrieve information from Apple Mail 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 mailbox data without modifying state, aligning with the Read category. While the tool description is empty, the name and server context strongly indicate a query/list operation. Severity is low because listing mailboxes poses minimal risk — it exposes organizational metadata but does not compromise email content, alter system state, or execute arbitrary commands.
From the tool's definition Tool name 'list-mailboxes' indicates retrieval of mailbox information. Server description states the MCP allows 'read, send, search, and manage emails' — listing mailboxes is a read operation with no side effects.
Documented attack patterns abuse exactly the kind of access list-mailboxes gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Apple Mail, and nothing reaches the server without passing your rules. This is the rule we recommend for list-mailboxes:
{
"version": "1",
"default": "deny",
"tools": {
"list-mailboxes": {}
}
}list-mailboxes is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
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list-mailboxes. It is categorised as a Read tool in the Apple Mail MCP Server, which means it retrieves data without modifying state.
Register the Apple Mail MCP server in PolicyLayer and add a rule for list-mailboxes: 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 Apple Mail. Nothing to install.
list-mailboxes 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-mailboxes 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-mailboxes. 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-mailboxes is provided by the Apple Mail MCP server (sweetrb/apple-mail-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 40 Apple Mail tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
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40 Apple Mail tools catalogued and risk-classified — across an index of 42,500+ MCP servers.