AI agents use save-attachment 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.
Saving attachments creates new files on the user's filesystem, which is a reversible Write operation. While not destructive, it modifies local state and could be exploited to write malicious files if an agent mishandles untrusted email attachments. Confidence is slightly reduced because the description is empty, leaving attachment handling details unspecified.
From the tool's definition Tool name 'save-attachment' indicates file creation/writing to disk. Server context confirms interaction with Apple Mail on macOS via AppleScript, enabling local file system modifications.
Documented attack patterns abuse exactly the kind of access save-attachment 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 save-attachment:
{
"version": "1",
"default": "deny",
"tools": {
"save-attachment": {
"limits": [
{
"counter": "save-attachment_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}save-attachment 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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save-attachment. 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 save-attachment: 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.
save-attachment 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 save-attachment 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 save-attachment. 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.
save-attachment 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.