# upload_sieve_script

Upload and activate a custom Sieve script for a mailbox. This replaces any visual filters. The server validates syntax before activating. Agency plan only. Dangerous extensions (vnd.dovecot.pipe, vnd.dovecot.execute, vnd.dovecot.filter) are blocked.

Agent View of the PolicyLayer registry record for `upload_sieve_script`. HTML page: https://policylayer.com/tools/trekmail-mcp-server/upload-sieve-script

## Facts

- Tool: `upload_sieve_script`
- Server: TrekMail MCP Server (`trekmail/mcp-server`) — https://policylayer.com/tools/trekmail-mcp-server.md
- Homepage: https://github.com/trekmail/mcp-server
- Risk category: Execute (High 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": "upload_sieve_script",
    "arguments": {}
  }
}
```

## Why upload_sieve_script is rated High

Sieve scripts are executable programs that run server-side to filter, redirect, or manipulate email. Uploading and activating one constitutes running code on the mail server. It also irreversibly replaces existing visual filters, though the script itself can be overwritten again.

From the tool's own definition: "'Upload and activate a custom Sieve script for a mailbox. This replaces any visual filters.' — uploads and activates executable mail-filtering logic; 'The server validates syntax before activating' confirms code execution path."

## Use case

AI agents invoke upload_sieve_script to trigger actions in TrekMail MCP Server. What it does depends on the arguments the agent supplies, and its effects often reach beyond the immediate call: builds kicked off, notifications sent, workflows started.

## 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": {
    "upload_sieve_script": {
      "limits": [
        {
          "counter": "upload_sieve_script_rate",
          "window": "minute",
          "max": 10,
          "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