upstageai/korean-tax-calc-mcp is a tax adjustment MCP server released by Upstage, based on Korean tax law. Feed it ledger-style entries and it carries out item determination, adjustment under tax law, and tax adjustment (income disposition), returning the results annotated with the governing legal provisions and the calculation formulas. It is written in Python and licensed under MIT. The most recent release is v0.10.0, and the source record does not state what changed in this release.
MCP is a protocol through which agents call external tools in a defined way and receive results. This server deals only with Korean domestic tax rules: it applies tax rates, thresholds and deduction rates in code and returns VAT, income tax and corporate tax amounts along with the tax adjustment, the intermediate calculations and the governing legal provisions. Since the amounts come out of the code rather than out of a generative model's estimate, an agent can trace the calculation basis instead of only receiving a result. Yearly tax rates and thresholds are pulled from a year table inside the code, and the criteria for judging individual items are separated out into glossary data that carries the applicable period and the governing legal provision. Excluding the three PDF tools, 59 calculation and judgment tools run locally.
That said, the procedure itself is only the known order of tax law transferred into code, and it does not present a new calculation methodology. For a year that has no entry in the year table, it does not estimate but stops the calculation, and it does not calculate when an input is missing or a value is unknown. The repository has 3 stars, and the materials contain no real application cases. It can be seen as a tool worth referring to when checking Korean tax calculation results inside an agent.