apibase

Phone Number Lookup (Twilio)

phone.twilio.lookup

Read-onlyIdempotent

Validate and look up phone number info — format validation, country, national format. Optional: carrier name, line type (mobile/landline/VoIP), caller name CNAM (Twilio)

Input Schema

TableJSON Schema

Name	Required	Description
`phone_number`	Yes	Phone number in E.164 format (e.g. "+14157012311", "+442071234567")
`include_carrier`	No	Include carrier/line type info (costs extra credit). Returns carrier name, line type (mobile/landline/voip).
`include_caller_name`	No	Include caller name CNAM lookup (costs extra credit). US numbers only.

Output Schema

TableJSON Schema

Name	Required	Description	Default
`error`	No	Present only when the call failed. Includes error code, message, request_id, and any provider-specific extras.
`result`	No	Tool response payload. Shape varies per tool — consult the tool description and inputSchema. May be an object, array, string, or number depending on the upstream provider response.

Schema Changelog

Changes observed during successful MCP inspections.

First observedSep 22, 2026

TDQS

A4/5.0

Behavior4/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Adds context beyond annotations: optional parameters cost extra credit, caller name is US-only. Annotations already cover safety/idempotency. Good disclosure of costs and restrictions.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Single sentence, well-structured with main purpose first, then optional details. No wasted words.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness5/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Covers validation and optional lookups. Output schema exists, so return values need no explanation. Complete for a lookup tool.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters4/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Description adds value beyond schema by noting costs and US-only restriction for caller name. Schema coverage is 100%, but description enhances understanding.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose4/5

Does the description clearly state what the tool does and how it differs from similar tools?

Description clearly states the tool does phone number validation and lookup, listing returned fields. It doesn't explicitly distinguish from sibling phone tools but is clear enough.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines3/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

No explicit guidance on when to use vs. alternatives, but the description implies simple lookup use. Annotations indicate safety, but no when-not-to-use.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

All apibase tools Inspect

Try in Browser

One endpoint for every MCP toolRayrun runs every MCP server behind one URL and holds the credentials. Each call is decided per client, tool, and argument, then recorded.ray.runAd

Glama MCP Gateway

Add one secure layer between your agents and this server.