# 0006. Country rules are data

- Status: Accepted
- Date: 2026-10-27

## Context

Tax rates, rounding rules and receipt requirements differ by country and change over time. Hard-coding Malaysian rules would make every other country a fork.

## Decision

Country-specific rules (tax codes and rates, cash rounding, required receipt fields) live as data in a country pack, validated by a JSON schema. Malaysia (`packages/country-my`) is the first pack. `packages/core` implements the generic calculations and reads rates and codes from the pack.

## Consequences

- No Malaysian rate or code is hard-coded outside `packages/country-my`.
- Each pack ships test vectors (`fixtures/vectors.json`) that any implementation can check itself against.
- Supporting another country is a contribution of a new pack, not a fork.