Open a specific mailbox (folder) and optionally retrieve sent mailbox info. Due to IMAP protocol limitations, only one mailbox stays open. Auto-connects if not already connected.
AI agents call open_mailbox to retrieve information from Mcp Mail Server without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool opens/selects a mailbox folder for reading and retrieves mailbox metadata. It does not send, delete, or modify any messages. The 'open' operation is a read-only IMAP SELECT or EXAMINE command that prepares the mailbox for subsequent read operations. Auto-connect side effect is minor infrastructure setup, not data modification.
From the tool's definition Open a specific mailbox (folder) and optionally retrieve sent mailbox info
Attacks that exploit this kind of access
Open a specific mailbox (folder) and optionally retrieve sent mailbox info. Due to IMAP protocol limitations, only one mailbox stays open. Auto-connects if not already connected. It is categorised as a Read tool in the Mcp Mail Server MCP Server, which means it retrieves data without modifying state.
Register the Mcp Mail Server MCP server in PolicyLayer and add a rule for open_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 Mcp Mail Server. Nothing to install.
open_mailbox 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 open_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 open_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.
open_mailbox is provided by the Mcp Mail Server MCP server (mcp-mail-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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