Cross-account, cross-folder search. Pass at least one of query/from/subject/date_from/date_to/unread_only. For Gmail accounts the search uses X-GM-RAW (same engine as the web UI). For QQ/163/126/sina/outlook (broken IMAP SEARCH), automatically falls back to client-side envelope filtering. Bounded...
AI agents call email_search to retrieve information from MCP Email Service without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
email_search performs data retrieval and querying operations only. It searches across email accounts and folders to find messages matching specified criteria, returning partial or complete results based on timeout behavior. No data is created, modified, deleted, or destroyed.
From the tool's definition Tool description explicitly states "Cross-account, cross-folder search" with parameters for querying (query/from/subject/date_from/date_to/unread_only).
Documented attack patterns abuse exactly the kind of access email_search gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and MCP Email Service, and nothing reaches the server without passing your rules. This is the rule we recommend for email_search:
{
"version": "1",
"default": "deny",
"tools": {
"email_search": {}
}
}email_search is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
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Cross-account, cross-folder search. Pass at least one of query/from/subject/date_from/date_to/unread_only. For Gmail accounts the search uses X-GM-RAW (same engine as the web UI). For QQ/163/126/sina/outlook (broken IMAP SEARCH), automatically falls back to client-side envelope filtering. Bounded by timeout_ms (default 60s) — past it returns partial results with timed_out=true; narrow with account_id/folder for speed. It is categorised as a Read tool in the MCP Email Service MCP Server, which means it retrieves data without modifying state.
Register the MCP Email Service MCP server in PolicyLayer and add a rule for email_search: 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 Email Service. Nothing to install.
email_search 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 email_search 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 email_search. 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.
email_search is provided by the MCP Email Service MCP server (leeguooooo/mailbox). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from MCP Email Service, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
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16 MCP Email Service tools catalogued and risk-classified — across an index of 43,000+ MCP servers.