Create a new mail filter for a mailbox. Filters automatically process incoming email based on conditions (sender, subject, body, size) and perform actions (move to folder, forward, flag, discard, reject). Pro and Agency plans only.
AI agents use create_mail_rule to create or update resources in TrekMail MCP Server — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your TrekMail MCP Server environment.
This tool creates email filters that modify how messages are processed, which constitutes a Write operation (creation of new mail handling rules). The severity is high because misconfigured filters could cause legitimate emails to be lost, forwarded to wrong parties, or discarded—affecting email delivery and user communications.
From the tool's definition Tool creates a new mail filter that automatically processes incoming email and performs actions like move to folder, forward, flag, discard, or reject. These are reversible modifications to email handling behavior.
Attacks that exploit this kind of access
Create a new mail filter for a mailbox. Filters automatically process incoming email based on conditions (sender, subject, body, size) and perform actions (move to folder, forward, flag, discard, reject). Pro and Agency plans only. It is categorised as a Write tool in the TrekMail MCP Server MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the TrekMail MCP Server MCP server in PolicyLayer and add a rule for create_mail_rule: 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 TrekMail MCP Server. Nothing to install.
create_mail_rule 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 create_mail_rule 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 create_mail_rule. 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.
create_mail_rule is provided by the TrekMail MCP Server MCP server (trekmail/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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