List all mailbox folders (INBOX, Sent, Drafts, Trash, etc.) with message counts and unread counts
AI agents call proton_list_folders to retrieve information from Proton MCP Server without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool performs a query-like operation to list and retrieve information about email folders. It has no side effects—it does not create, modify, delete, or execute actions. The data returned is read-only metadata about the mailbox structure. Even in a misuse scenario, an AI agent cannot cause harm by repeatedly listing folders.
From the tool's definition Tool name 'proton_list_folders' and description 'List all mailbox folders' indicate a retrieval operation that enumerates folder metadata (message counts, unread counts) without modifying or deleting data.
Attacks that exploit this kind of access
List all mailbox folders (INBOX, Sent, Drafts, Trash, etc.) with message counts and unread counts. It is categorised as a Read tool in the Proton MCP Server MCP Server, which means it retrieves data without modifying state.
Register the Proton MCP Server MCP server in PolicyLayer and add a rule for proton_list_folders: 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 Proton MCP Server. Nothing to install.
proton_list_folders 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 proton_list_folders 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 proton_list_folders. 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.
proton_list_folders is provided by the Proton MCP Server MCP server (sugar-crash-studios/proton-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Every MCP server has a record like this.
Type a name, get the same breakdown: verified identity, auth posture, risk grade, capabilities, recommended policy.
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