AI agents call listFolders to retrieve information from Mail MCP Tool without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool appears to list email folders (inbox, sent, archive, etc.) - a standard read operation that retrieves metadata about folder structure. It has no capability to modify, delete, or execute operations. The blast radius of misuse is minimal, as listing folders only exposes organizational structure of the mailbox without accessing content or modifying anything.
From the tool's definition Tool name 'listFolders' and context within an email management MCP server indicate this retrieves folder/directory information.
Documented attack patterns abuse exactly the kind of access listFolders gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Mail MCP Tool, and nothing reaches the server without passing your rules. This is the rule we recommend for listFolders:
{
"version": "1",
"default": "deny",
"tools": {
"listFolders": {}
}
}listFolders is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
Free to start. No card required.
listFolders. It is categorised as a Read tool in the Mail MCP Tool MCP Server, which means it retrieves data without modifying state.
Register the Mail MCP Tool MCP server in PolicyLayer and add a rule for listFolders: 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 Mail MCP Tool. Nothing to install.
listFolders 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 listFolders 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 listFolders. 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.
listFolders is provided by the Mail MCP Tool MCP server (shuakami/mcp-mail). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 17 Mail MCP Tool tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
Free to start. No card required.
17 Mail MCP Tool tools catalogued and risk-classified — across an index of 42,500+ MCP servers.