# sms_lookup_number

A read tool on the Twilio SMS MCP Server MCP server.

Agent View of the PolicyLayer registry record for `sms_lookup_number`. HTML page: https://policylayer.com/tools/0x-professor-twilio-mcp-server/sms-lookup-number

## Facts

- Tool: `sms_lookup_number`
- Server: Twilio SMS MCP Server (`0x-professor/twilio-mcp-server`) — https://policylayer.com/tools/0x-professor-twilio-mcp-server.md
- Homepage: https://github.com/0x-Professor/Twilio-mcp-server
- Risk category: Read (Low risk)
- Registry record: grade F, identity unverified
- Server rate-limited: no
- Parameters: 0
- Recommended policy verdict: Allowed

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

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

## Why sms_lookup_number is rated Low

Based on naming convention and server context, this tool likely performs a phone number lookup or validation—a read-only query with no data modification or execution side effects. The empty description reduces confidence slightly, but the consistent pattern of read tools on this Twilio SMS server and the lookup verb (not send, delete, execute, or modify) strongly suggest a Read category.

From the tool's own definition: "Tool name 'sms_lookup_number' suggests querying phone number information. No description provided, but the sibling tools on this server (sms_get_message, sms_list_inbox, sms_list_sent, sms_get_conversation) are all read operations, establishing a pattern of…"

## Use case

AI agents call sms_lookup_number to retrieve information from Twilio SMS MCP Server without modifying anything. It is typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.

## Recommended policy (PolicyLayer)

Verdict: **Allowed**. Enforced by the PolicyLayer MCP gateway (https://policylayer.com/mcp-gateway) before a call reaches Twilio SMS MCP Server:

```json
{
  "version": "1",
  "default": "deny",
  "tools": {
    "sms_lookup_number": {}
  }
}
```

## Other tools on Twilio SMS MCP Server (15)

- `sms_cancel_scheduled` — Destructive — https://policylayer.com/tools/0x-professor-twilio-mcp-server/sms-cancel-scheduled.md
- `sms_delete_message` — Destructive — https://policylayer.com/tools/0x-professor-twilio-mcp-server/sms-delete-message.md
- `sms_account_info` — Read — https://policylayer.com/tools/0x-professor-twilio-mcp-server/sms-account-info.md
- `sms_format_number` — Read — https://policylayer.com/tools/0x-professor-twilio-mcp-server/sms-format-number.md
- `sms_get_conversation` — Read — https://policylayer.com/tools/0x-professor-twilio-mcp-server/sms-get-conversation.md
- `sms_get_message` — Read — https://policylayer.com/tools/0x-professor-twilio-mcp-server/sms-get-message.md
- `sms_list_inbox` — Read — https://policylayer.com/tools/0x-professor-twilio-mcp-server/sms-list-inbox.md
- `sms_list_numbers` — Read — https://policylayer.com/tools/0x-professor-twilio-mcp-server/sms-list-numbers.md
- `sms_list_sent` — Read — https://policylayer.com/tools/0x-professor-twilio-mcp-server/sms-list-sent.md
- `sms_redact_message` — Read — https://policylayer.com/tools/0x-professor-twilio-mcp-server/sms-redact-message.md
- `sms_usage_stats` — Read — https://policylayer.com/tools/0x-professor-twilio-mcp-server/sms-usage-stats.md
- `sms_mark_read` — Write — https://policylayer.com/tools/0x-professor-twilio-mcp-server/sms-mark-read.md
- `sms_schedule` — Write — https://policylayer.com/tools/0x-professor-twilio-mcp-server/sms-schedule.md
- `sms_send` — Write — https://policylayer.com/tools/0x-professor-twilio-mcp-server/sms-send.md
- `sms_send_bulk` — Write — https://policylayer.com/tools/0x-professor-twilio-mcp-server/sms-send-bulk.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=0x-professor-twilio-mcp-server · API: https://policylayer.com/registry/api · Policy library: https://policylayer.com/policies/0x-professor-twilio-mcp-server