Nsa MCP Server

mcp-nsa

Installation (one command)

Published on npm + the MCP Registry (io.github.matematicsolutions/mcp-nsa). Run without cloning:

npx -y @matematicsolutions/mcp-nsa

MCP client configuration (stdio):

{ "mcpServers": { "mcp-nsa": { "command": "npx", "args": ["-y", "@matematicsolutions/mcp-nsa"] } } }

(Building from source - below.)

MCP server for the case law of the Polish administrative courts - Naczelny Sad Administracyjny / NSA (Supreme Administrative Court) + 16 Wojewodzkie Sady Administracyjne / WSA (regional administrative courts) - via CBOSA (Centralna Baza Orzeczen Sadow Administracyjnych - the administrative courts' central case-law database) (orzeczenia.nsa.gov.pl).

Why

SAOS (the common-courts case-law analysis system) does not index the administrative courts. Yet that is exactly where the substantive case law lives:

• GDPR / data protection - decisions of the President of UODO appealed to the WSA, cassation appeals to the NSA
• Taxes - individual tax rulings, decisions of tax authorities
• Customs and excise
• Administrative permits, concessions
• Review of public-administration activity

mcp-nsa closes this gap. Coverage: 2,390,000+ rulings (verified live 2026-07-08 across the full date range), from 1981 to today.

Tools

• search(query, caseNumber?, court?, dateFrom?, dateTo?, pageNumber?)
  • search by keyword, case number, court, date. Fetches the top 5 full rulings (case number, court, date, panel, keywords, legal basis, excerpt).
• get_judgment(doc_id) - full ruling by 10-character hex doc_id (from the CBOSA URL, e.g. 7E50984BB7).
• search_by_case(caseNumber) - shortcut: search by case number (e.g. III OSK 1377/23, I SA/Gl 659/22).

Every response contains structuredContent.citations with the fields: title, url (CBOSA), case_number, court, judgment_date, decision_type, snippet, doc_id. Patron reads this field automatically and surfaces it in the UI panel as the section "Rulings from CBOSA (NSA / WSA - administrative courts)".

Stack

• Node 18+
• @modelcontextprotocol/sdk
• Stdio transport
• https + regex HTML parser (zero external deps beyond the SDK)
• 500 ms throttle between requests (2 req/s)
• SSL: rejectUnauthorized: false - the CBOSA chain is sometimes incomplete on some machines; public rulings, no PII, MITM risk negligible against the benefit. See: LDH issue #167.

Build + run

npm install
npm run build
node dist/index.js   # starts the server on stdio

Wiring into Patron

In patron/backend/mcp-servers.json (alongside mcp-saos and mcp-eu-sparql):

{
  "name": "nsa",
  "transport": "stdio",
  "command": "node",
  "args": ["C:/Users/<YOUR-USERNAME>/mcp-nsa/dist/index.js"],
  "enabled": true
}

Smoke test

echo '{"jsonrpc":"2.0","id":1,"method":"initialize","params":{"protocolVersion":"2024-11-05","capabilities":{},"clientInfo":{"name":"s","version":"0"}}}
{"jsonrpc":"2.0","method":"notifications/initialized"}
{"jsonrpc":"2.0","id":2,"method":"tools/call","params":{"name":"search","arguments":{"query":"RODO art 6"}}}' \
  | node dist/index.js

Should return ~1500 hits + the top 5 with Polish NSA/WSA case numbers + CBOSA URLs

• structuredContent.citations.

Lineage

Implementation rewritten in TypeScript on the basis of the HTTP/HTML contract from legal-data-hunter/sources/PL/NSA (Python + BeautifulSoup, MIT). It does not import the source code - it reproduces the query pattern and HTML parsing.

License

MIT.

Part of the MateMatic legal stack

This server is one of five MCP connectors covering Polish jurisdiction + EU law, used by Patron (AGPL-3.0) and any other MCP-aware legal AI agent.

• mcp-nsa (this repo) - NSA + 16 WSA administrative courts (CBOSA)
• mcp-saos - common courts, SN, TK, KIO
• mcp-isap - Polish legislation (Dz.U. + M.P.)
• mcp-krs - Polish company registry (KRS)
• mcp-eu-sparql - EU law + CJEU (EUR-Lex)

All five MCP servers share the same structuredContent.citations contract: each tool returns an array of {title, url, snippet?, ...metadata} that legal agents can render directly in their citation panel.

See matematicsolutions/.github for the full org profile.