sinch-number-lookup-api

sinch-number-lookup-api is a skill for Claude Code, Codex from sinch/skills. It costs 54 tokens per session (2,920 once invoked), scanned A, original, Apache-2.0.

A workflow for looking up details about a phone number through Sinch’s Number Lookup API. It can identify the carrier, line type, porting history, SIM-swap status, VoIP use, and whether the number may have been reassigned.

In plain words
What is it for?
Use it to check phone numbers one at a time for carrier and network details, porting, SIM swaps, VoIP detection, or reassignment.
Why use it?
It provides information that can help detect fraud, choose a routing path, or keep contact data accurate.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Good fit Use it to check phone numbers one at a time for carrier and network details, porting, SIM swaps, VoIP detection, or reassignment.

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Install with agentmods
npx agentmods add skills/sinch/skills/sinch-number-lookup-api
Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Any agent
npx skills add sinch/skills --skill sinch-number-lookup-api
Clone the repo
git clone --depth 1 https://github.com/sinch/skills

Made for: Claude Code, Codex.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for sinch-number-lookup-api

README.md
[![agentmods](https://agentmods.dev/badge/skills/sinch/skills/sinch-number-lookup-api/github.svg)](https://agentmods.dev/skills/sinch/skills/sinch-number-lookup-api)
Your own site
<a href="https://agentmods.dev/skills/sinch/skills/sinch-number-lookup-api"><img src="https://agentmods.dev/badge/skills/sinch/skills/sinch-number-lookup-api/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for sinch-number-lookup-api

Your own site · 80×15
<a href="https://agentmods.dev/skills/sinch/skills/sinch-number-lookup-api"><img src="https://agentmods.dev/badge/skills/sinch/skills/sinch-number-lookup-api.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 54 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,920 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 1 finding. A grade says what 26 rules found in the file — not that it is safe. Third-party audits
  • NVIDIA SkillSpector warn 7 Sept 2026
SkillSpector: 1 finding, up to medium

These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →

  • medium Data Exfiltration · line 85
    Data is being sent to an external URL. This could be legitimate telemetry or data exfiltration. Manual review is recommended.
    Fix: Verify the destination URL is trusted and necessary. Remove or replace with documented APIs. Ensure no secrets, tokens, or PII are transmitted.
How audits are shown
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00054 $0.02920
Opus 5 $0.00027 $0.01460
Sonnet 5 $0.00011 $0.00584
Haiku 4.5 $0.00005 $0.00292

Measured 10d ago against content hash 251fde709ad8, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-10, from the pricing page.

Security

Grade A, and why

sinch-number-lookup-api scanned grade A with 1 finding against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 10d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Makes network callslowCapability

Not a fault in itself. Listed so you know the mod talks to something, and to what.

1. **Approach** — SDK or direct API calls (curl/fetch/requests)?
Origin

Copies of this mod

1 near-identical copy found in the catalogue:

skills/sinch-number-lookup-api/SKILL.md · 218 lines

How it starts

The opening of the file, as written. The whole thing — 218 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Sinch Number Lookup API

Overview

Queries phone numbers for carrier, line type, porting, SIM swap, VoIP detection, and reassigned number detection. Used for fraud prevention, routing, and data enrichment. One number per request — no batch endpoint.

Agent Instructions

Before generating code, gather from the user (skip any item already specified in the prompt or context):

  1. Approach — SDK or direct API calls (curl/fetch/requests)?
  2. Language — for SDK: Node.js or Python (partial). For direct API: any language, or curl. Java and .NET must use direct HTTP — there is no SDK wrapper.

When the user chooses SDK, refer to the sinch-sdks skill for installation and client initialization, then to the API Reference linked in Links.

When the user chooses direct API calls, refer to the API Reference linked in Links for request/response schemas.

Security: See the Security section below for url fetching policy and credential handling.

Source of Truth — what to load, and what is authoritative

This skill has two kinds of content with UNEQUAL reliability. Follow this precedence:

  1. Canonical docs at developers.sinch.com (AUTHORITATIVE). The .md doc links in this skill are the single source of truth for exact request/response schemas, field names and nesting, enum values, signature/auth schemes, and limits. Before writing code that constructs a payload, verifies a signature, or parses a callback/response, fetch the specific linked doc and confirm the exact shape there. Fetching first-party developers.sinch.com URLs is permitted by the Security/URL policy. Never invent, guess, or pattern-extrapolate a documentation URL — only fetch doc URLs written verbatim in this skill or reached by following a link on a page you already fetched; a trusted domain does not make a guessed path real.
  2. This SKILL.md's own tables, field lists, and snippets (SUMMARIES — not authoritative). They orient you and point at the right canonical doc; they may lag, omit fields, or simplify nesting. Use them to decide what to build and which doc to open. Do NOT transcribe a field name, nesting, encoding, or enum from this file into shipped code without confirming it in the tier-1 doc. If a detail appears only in a summary, treat it as unverified and say so.

Read the full file on GitHub · 218 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 10d ago First seen · 218 lines · 54 tokens per session scan A 251fde709ad8

Subscribe to this mod's changes

sinch-number-lookup-api is a skill published in the GitHub repository sinch/skills (10 stars, last pushed yesterday), licensed Apache-2.0. It adds 54 tokens to every session and 2,920 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it A with 1 finding (makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.