Save an email attachment to disk. Use mail.read_message first to see available attachments and their indices. Returns the saved file path. Requires Mail.app to be running.
AI agents use mail.save_attachment to create or update resources in Orchard — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Orchard environment.
The tool irreversibly writes data to the user's filesystem. While not destructive (files can be deleted), and not a read-only operation, it modifies the local file system by saving email attachments.
From the tool's definition Tool explicitly performs file creation/modification on disk: "Save an email attachment to disk" and "Returns the saved file path." This is a write operation that creates new files in the filesystem.
Documented attack patterns abuse exactly the kind of access mail.save_attachment gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Orchard, and nothing reaches the server without passing your rules. This is the rule we recommend for mail.save_attachment:
{
"version": "1",
"default": "deny",
"tools": {
"mail.save_attachment": {
"limits": [
{
"counter": "mail.save_attachment_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}mail.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 an email attachment to disk. Use mail.read_message first to see available attachments and their indices. Returns the saved file path. Requires Mail.app to be running. It is categorised as a Write tool in the Orchard MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Orchard MCP server in PolicyLayer and add a rule for mail.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 Orchard. Nothing to install.
mail.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 mail.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 mail.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.
mail.save_attachment is provided by the Orchard MCP server (l22-io/orchard-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Orchard, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
Free to start. No card required.
65 Orchard tools catalogued and risk-classified — across an index of 43,000+ MCP servers.