# create_mail_rule

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.

Agent View of the PolicyLayer registry record for `create_mail_rule`. HTML page: https://policylayer.com/tools/trekmail-mcp-server/create-mail-rule

## Facts

- Tool: `create_mail_rule`
- Server: TrekMail MCP Server (`trekmail/mcp-server`) — https://policylayer.com/tools/trekmail-mcp-server.md
- Homepage: https://github.com/trekmail/mcp-server
- Risk category: Write (Medium risk)
- Registry record: grade F, identity unverified
- Server rate-limited: no
- Parameters: 0
- Recommended policy verdict: Rate-limited

## Example call (MCP tools/call, JSON-RPC 2.0)

```json
{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "tools/call",
  "params": {
    "name": "create_mail_rule",
    "arguments": {}
  }
}
```

## Why create_mail_rule is rated Medium

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 own 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."

## Use case

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.

## Recommended policy (PolicyLayer)

Verdict: **Rate-limited**. Enforced by the PolicyLayer MCP gateway (https://policylayer.com/mcp-gateway) before a call reaches TrekMail MCP Server:

```json
{
  "version": "1",
  "default": "deny",
  "tools": {
    "create_mail_rule": {
      "limits": [
        {
          "counter": "create_mail_rule_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}
```

## Other tools on TrekMail MCP Server (247)

- `bulk_action` — Destructive — https://policylayer.com/tools/trekmail-mcp-server/bulk-action.md
- `cancel_bulk_migration` — Destructive — https://policylayer.com/tools/trekmail-mcp-server/cancel-bulk-migration.md
- `cancel_migration` — Destructive — https://policylayer.com/tools/trekmail-mcp-server/cancel-migration.md
- `cancel_scheduled` — Destructive — https://policylayer.com/tools/trekmail-mcp-server/cancel-scheduled.md
- `change_mailbox_password` — Destructive — https://policylayer.com/tools/trekmail-mcp-server/change-mailbox-password.md
- `confirm_delete_intent` — Destructive — https://policylayer.com/tools/trekmail-mcp-server/confirm-delete-intent.md
- `create_delete_intent` — Destructive — https://policylayer.com/tools/trekmail-mcp-server/create-delete-intent.md
- `delete_alias` — Destructive — https://policylayer.com/tools/trekmail-mcp-server/delete-alias.md
- `delete_bulk_migration` — Destructive — https://policylayer.com/tools/trekmail-mcp-server/delete-bulk-migration.md
- `delete_calendar_event` — Destructive — https://policylayer.com/tools/trekmail-mcp-server/delete-calendar-event.md
- `delete_cloudflare_token` — Destructive — https://policylayer.com/tools/trekmail-mcp-server/delete-cloudflare-token.md
- `delete_contact` — Destructive — https://policylayer.com/tools/trekmail-mcp-server/delete-contact.md
- `delete_contact_group` — Destructive — https://policylayer.com/tools/trekmail-mcp-server/delete-contact-group.md
- `delete_domain` — Destructive — https://policylayer.com/tools/trekmail-mcp-server/delete-domain.md
- `delete_domain_smtp_profile` — Destructive — https://policylayer.com/tools/trekmail-mcp-server/delete-domain-smtp-profile.md
- `delete_external_account` — Destructive — https://policylayer.com/tools/trekmail-mcp-server/delete-external-account.md
- `delete_folder` — Destructive — https://policylayer.com/tools/trekmail-mcp-server/delete-folder.md
- `delete_forwarding_address` — Destructive — https://policylayer.com/tools/trekmail-mcp-server/delete-forwarding-address.md
- `delete_identity` — Destructive — https://policylayer.com/tools/trekmail-mcp-server/delete-identity.md
- `delete_mail_rule` — Destructive — https://policylayer.com/tools/trekmail-mcp-server/delete-mail-rule.md
- `delete_message` — Destructive — https://policylayer.com/tools/trekmail-mcp-server/delete-message.md
- `delete_migration` — Destructive — https://policylayer.com/tools/trekmail-mcp-server/delete-migration.md
- `delete_smtp_connection` — Destructive — https://policylayer.com/tools/trekmail-mcp-server/delete-smtp-connection.md
- `delete_template` — Destructive — https://policylayer.com/tools/trekmail-mcp-server/delete-template.md
- `drive_bulk_purge` — Destructive — https://policylayer.com/tools/trekmail-mcp-server/drive-bulk-purge.md
- `drive_bulk_trash` — Destructive — https://policylayer.com/tools/trekmail-mcp-server/drive-bulk-trash.md
- `drive_device_revoke` — Destructive — https://policylayer.com/tools/trekmail-mcp-server/drive-device-revoke.md
- `drive_file_purge` — Destructive — https://policylayer.com/tools/trekmail-mcp-server/drive-file-purge.md
- `drive_file_trash` — Destructive — https://policylayer.com/tools/trekmail-mcp-server/drive-file-trash.md
- `drive_folder_purge` — Destructive — https://policylayer.com/tools/trekmail-mcp-server/drive-folder-purge.md
- …and 217 more: https://policylayer.com/tools/trekmail-mcp-server.md

## For agents

This record is a snapshot. Live verdicts and the full registry:

- Check every server in your MCP config at once: `npx -y policylayer stack`
- Vet a server before you add it: install the mcp-precheck skill — `npx skills add https://policylayer.com` (skill text: https://policylayer.com/skill.md)
- Query the registry over MCP: endpoint `https://api.policylayer.com/mcp` — tools `check_mcp_server`, `check_mcp_stack`, `check_tool`, `search_registry`, `get_change_events`

---

Source: the PolicyLayer MCP registry — one continuously verified record per MCP server. Full record: https://policylayer.com/registry?q=trekmail-mcp-server · API: https://policylayer.com/registry/api · Policy library: https://policylayer.com/policies/trekmail-mcp-server