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io.github.qinisolabs/localecheck

Official registry Finance and payments

Verified locale data for AI agents: dates, phone, currency, tax, holidays, addresses (UK/US)

Source code Documentation

Install

Add this to your client's MCP configuration (Claude Desktop: claude_desktop_config.json; Cursor: .cursor/mcp.json; VS Code and others use the same "mcpServers" shape).

NPM package localecheck
Claude Code 
claude mcp add localecheck -- npx -y localecheck@0.1.1
JSON configuration (Claude Desktop, Cursor, VS Code) 
{
    "mcpServers": {
        "localecheck": {
            "command": "npx",
            "args": [
                "-y",
                "localecheck@0.1.1"
            ]
        }
    }
}

Documentation

From the project's README on GitHub, refreshed weekly. Links open on GitHub.

Contents
  1. localecheck
  2. Packages
  3. What it does
  4. Quick start (in an AI app)
  5. Repo map
  6. Status & caveats

localecheck

Locale-correctness tools for AI agents. Agents are systematically wrong about everyday non-US data — they read 03/04 as March 4 in the UK, apply today's VAT rate to a historical invoice, format €1,234.50 for a German reader, and miss bank holidays in delivery dates. localecheck gives them verified answers and flags impossible inputs instead of guessing.

Coverage: UK + USA (v1), expanding. Free, no API key.

Packages

PackageInstallUse
TypeScript (primary)packages/localecheck-tsnpx -y localecheck (live on npm)MCP server and importable library
Pythonpackages/localecheck-pythonfrom source (PyPI release coming soon)MCP server, importable library, REST API

Both wrap the same authoritative libraries (libphonenumber, CLDR/Intl, date-holidays) and share the same hand-curated tax data.

What it does

parse_date · validate_phone · format_currency · tax_rate (VAT/sales-tax by date) · is_holiday / next_holiday · parse_address

Quick start (in an AI app)

{ "mcpServers": { "localecheck": { "command": "npx", "args": ["-y", "localecheck"] } } }

Then ask naturally — the agent picks the tool: "A UK invoice dated 1 June 2009 — what VAT rate?" → 15%.

Repo map

  • packages/localecheck-ts — primary TypeScript package (MCP + library)
  • packages/localecheck-python — Python package + FastAPI REST API
  • eval/ — benchmark harness: how often raw LLMs get this wrong
  • benchmark.html — shareable results page · BUSINESS_MODEL.md — strategy · PUBLISH.md — release steps · LOCAL_TEST.md — test before publishing

Status & caveats

UK VAT history is reliable for the modern era (standard rate). US state sales-tax values are 2025 state base rates (local taxes add on top) — verify against an authoritative feed before live invoicing. Addresses parse + extract a valid postcode/ZIP but don't verify deliverability.

Code: Apache-2.0. Curated tax data: see BUSINESS_MODEL.md.

Frequently asked questions

What is io.github.qinisolabs/localecheck?

Verified locale data for AI agents: dates, phone, currency, tax, holidays, addresses (UK/US)

How do I install io.github.qinisolabs/localecheck?

It runs on your machine. In Claude Code: claude mcp add localecheck -- npx -y localecheck@0.1.1. For other clients, paste the JSON configuration from this page into their MCP settings.

Does io.github.qinisolabs/localecheck need an API key?

Its registry entry lists no required key or secret. Some features may still need an account with the service it connects to.

Is io.github.qinisolabs/localecheck open source?

Yes. Its code is on GitHub under the Apache-2.0 license.

Who maintains io.github.qinisolabs/localecheck?

It is published by qinisolabs. AI.tn lists it but does not maintain or endorse it.

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