# update_domain_signature

Set the per-domain email signature. mode=off disables; mode=default seeds newly-created mailbox identities; mode=enforced overrides per-mailbox signatures on the webmail compose path. signature_html accepts safe HTML (up to 10000 chars); unsafe tags are stripped.

Agent View of the PolicyLayer registry record for `update_domain_signature`. HTML page: https://policylayer.com/tools/trekmail-mcp-server/update-domain-signature

## Facts

- Tool: `update_domain_signature`
- 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_domain_signature",
    "arguments": {}
  }
}
```

## Why update_domain_signature is rated Medium

This tool modifies domain-level email signature settings, which affects email presentation but does not delete data (Destructive), execute arbitrary code (Execute), create financial obligations (Financial), or retrieve data without side effects (Read). It is a reversible configuration change (can be toggled off or changed), making it Write.

From the tool's own definition: "Tool description states it 'Set[s] the per-domain email signature' with modes including 'off', 'default', and 'enforced', and accepts HTML input. The verbs 'set' and 'enforced' indicate modification of configuration data."

## Use case

AI agents use update_domain_signature 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_domain_signature": {
      "limits": [
        {
          "counter": "update_domain_signature_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