Localecheck

io.github.qinisolabsPublished by GitHub account qinisolabsv0.1.1Updated Oct 24, 2026

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

VerifiedSTDIODesktop onlyFinanceData & Analytics

Overview

AI-generated overview

A local MCP server giving assistants verified UK and US locale data: date parsing, phone validation, currency formatting, tax rates, holidays and addresses.

What you can do
Parse dates with UK/US day-month conventions and flag impossible inputs instead of guessing the format. Validate phone numbers and parse addresses, extracting a valid UK postcode or US ZIP. Format currency amounts for the reader's locale. Look up VAT or US state sales-tax rates by date, and check whether a date is a holiday or find the next one.
When to use it
Useful when an assistant handles UK or US invoices, delivery dates, contact details or prices and tends to misread day-month dates, apply current tax rates to old documents, or miss bank holidays.
Requirements
Runs locally over stdio, typically launched with npx from the npm package localecheck, so Node.js is needed. No API key and no environment variables are declared. Coverage is limited to the UK and USA in this version.
Before you install
US state sales-tax values are 2025 state base rates only, with local taxes excluded, and the README advises verifying against an authoritative feed before live invoicing. Address parsing extracts a postcode or ZIP but does not verify deliverability. Tax data has its own licensing terms separate from the Apache-2.0 code.

Installation

In SourceWeft

  1. Open Localecheck in the dashboard and add it to a workspace.
  2. Enable the server for the chats that should use its tools.

Desktop only via STDIO. STDIO servers start a local process, so they need the SourceWeft desktop host.

Other MCP clients

Follow the launch instructions in the repository.

README

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)

json
{ "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.

Source: README.md at commit e36fdbc

Tools

0
SourceWeft has not started this package in its sandbox yet, so its tools are not known.

Version history

1
  1. v0.1.1LatestSep 16, 2026

Score

50% of the applicable checks met

How complete this listing is, computed from the registry entry, the endpoint and public sources. Not a rating of the server and not a statement that it is safe or working today: reachability is a dated check, and no installs or reviews go into the score.

  • Reached in the last 30 days25 pts

    Keep the endpoint answering the MCP handshake; SourceWeft probes it every 30 days.

  • Auth declared10 pts

    Declare the credential headers in the registry entry, or keep the endpoint answering the probe so its auth can be classified.

  • Tools listed15 pts

    Answer tools/list without a credential, or ship a package that starts in a sandbox without one.

  • DescriptionRequired15 pts
  • Logo10 pts
  • Documentation15 pts
  • License10 pts