AI agents use create-mailbox to create or update resources in Apple Mail — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Apple Mail environment.
Creating a mailbox is a reversible write operation that modifies the mail account structure by adding a new folder. It has no destructive or financial impact. While the description is empty, the name and context from sibling tools clearly indicate this creates persistent state in the mail system.
From the tool's definition Tool name is 'create-mailbox' which creates a new mailbox/folder in Apple Mail. Sibling tools include 'delete-mailbox' (destructive), and many write/read operations like 'create-draft', 'batch-move-messages', indicating this server handles mail management…
Documented attack patterns abuse exactly the kind of access create-mailbox 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 create-mailbox:
{
"version": "1",
"default": "deny",
"tools": {
"create-mailbox": {
"limits": [
{
"counter": "create-mailbox_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}create-mailbox stays usable, but capped — an agent stuck in a loop can't make hundreds of changes a minute. Everything else on the server is denied unless you say otherwise.
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create-mailbox. It is categorised as a Write tool in the Apple Mail MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Apple Mail MCP server in PolicyLayer and add a rule for create-mailbox: 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.
create-mailbox is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.
Yes. Add a rate_limit block to the create-mailbox 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 create-mailbox. 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.
create-mailbox 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.