# update_mail_rule Update an existing mail filter. Pro and Agency plans only. Agent View of the PolicyLayer registry record for `update_mail_rule`. HTML page: https://policylayer.com/tools/trekmail-mcp-server/update-mail-rule ## Facts - Tool: `update_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": "update_mail_rule", "arguments": {} } } ``` ## Why update_mail_rule is rated Medium This tool modifies existing mail filter rules, which is a Write operation (reversible change to data). It does not delete rules (Destructive), execute arbitrary code (Execute), or move money (Financial). Severity is medium because misconfiguration of mail filters could cause emails to be misrouted or blocked, affecting email delivery and user productivity, but the change can be undone by updating the rule again. From the tool's own definition: "Tool description states 'Update an existing mail filter' - the word 'Update' indicates reversible modification of data (mail filter configuration)." ## Use case AI agents use update_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": { "update_mail_rule": { "limits": [ { "counter": "update_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