taxlaw-nts-mcp

An STDIO server that uses MCP tools to search data from the National Tax Law Information System (https://taxlaw.nts.go.kr).

It provides supplementary searches for National Tax Service (NTS) tax law interpretations, Q&A, tax appeal documents, basic rulings, tables/forms, publications, and Hometax consultation cases that are difficult to find directly through the Ministry of Government Legislation.

To allow access to menus that do not yet have dedicated high-level tools, it also provides tools for listing confirmed site menus/actions, raw action.do calls, and retrieving HTML text from the site.

English

How to use with korean-law-mcp

For tax law inquiries, we recommend a workflow where you first check the Ministry of Government Legislation/statute DB for laws, enforcement decrees, precedents, and tax tribunal decisions using korean-law-mcp, and then use this server for supplementary searches when you cannot find NTS interpretations, basic rulings, Hometax consultation cases, or publications in the Ministry of Government Legislation search.

When both MCPs find the same precedent, decision, or interpretation, consolidate them based on the document number/claim number/case number (with spaces and hyphens removed), production date/decision date, and title. Do not list identical items redundantly; include source IDs from both sides, and use the results from this server to supplement original text snippets, Hometax consultations, basic rulings, and publications that are only available in the National Tax Law Information System.

This server only displays items present in the National Tax Law Information System responses. If a search fails or an external site error occurs, it returns markers such as [NOT_FOUND], [EXTERNAL_API_ERROR], or [INVALID_PARAMETER] along with a warning against making guesses.

Related MCP server: LexLink-ko-mcp

Provided Tools

Accessing the Full Menu

First, use list_taxlaw_site_menus to check menu keys, URLs, confirmed actionId, and default paramData. For menus with dedicated tools, use the corresponding high-level tool; for menus without one, pass actionId, defaultParamData, and refererPath to call_taxlaw_action to retrieve the raw response. For materials provided as static HTML, such as summary information by tax item or tax law revision proposals, pass paths like /html/U_0101.html or /cm/USECMJ001M.do to get_taxlaw_page_text. Tax schedules can be retrieved by passing year and month to the ASECMC001MR01 action identified in list_taxlaw_site_menus(query="세무일정").

Quick Start

npm install
npm run build
npm start

To run from a local source path in an MCP client:

{
  "mcpServers": {
    "taxlaw-nts": {
      "command": "node",
      "args": ["/absolute/path/to/taxlaw-nts-mcp/build/index.js"]
    }
  }
}

After publishing to npm, you can register it more concisely after a global installation.

npm install -g taxlaw-nts-mcp

{
  "mcpServers": {
    "taxlaw-nts": {
      "command": "taxlaw-nts-mcp"
    }
  }
}

Environment Variables

No API key is required. You can change the User-Agent used for National Tax Law Information System calls when necessary.

TAXLAW_USER_AGENT="Mozilla/5.0 ..."

Error Response Policy

If there are no search or detail results, it returns [NOT_FOUND] and isError: true. External site errors are returned as [EXTERNAL_API_ERROR], and invalid inputs as [INVALID_PARAMETER]. The result body includes both the source URL and the actual ID retrieved.

Development

npm run build
npm run watch
npm pack --dry-run

License

MIT