Isap MCP Server

mcp-isap

Installation (one command)

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

npx -y @matematicsolutions/mcp-isap

MCP client configuration (stdio):

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

(Building from source - below.)

MCP server for Polish legislation - Dziennik Ustaw (Journal of Laws, DU) + Monitor Polski (MP) via the official Sejm ELI API (api.sejm.gov.pl/eli).

Why

mcp-saos (general courts) + mcp-nsa (administrative) + mcp-eu-sparql (EU) cover the case-law side. mcp-isap adds legislation - statutes, regulations, official announcements, international agreements. This closes the triad:

STATUTE + CASE LAW + EU LAW
   ↓         ↓          ↓
  ISAP    SAOS+NSA   EUR-Lex
   ↓         ↓          ↓
        law firm asks about GDPR
        → 4 connectors in parallel
        → 4 citation sections in the panel

Coverage: 96,000+ acts from 1918 to today. Full ELI support (European Legislation Identifier).

Tools

• search_acts(title?, year?, publisher?, type?, in_force?, limit?) - search by title fragment / year / publisher / act type / in-force status. publisher: DU (Dziennik Ustaw) or MP (Monitor Polski).
• get_act(eli) - act details by ELI (DU/2018/1000). Returns title, type, status, entry into force, keywords, links to HTML/PDF text and the ISAP page.
• get_act_text(eli, page?, search_text?) - the act's plain text (no HTML tags), paginated at 5000 characters per page. Iterate page while structuredContent.pagination.has_more is true, or pass search_text (e.g. "Art. 118.") to get the fragment around the first hit in one call. structuredContent.text_version says whether this is a consolidated text or the wording as promulgated - Sejm ELI serves the original wording for base acts, so for the law in force fetch the newest consolidated-text announcement listed in consolidated_text_eli. Acts published only as PDF return the text_unavailable_use_pdf error with links, never prose standing in for the provision.

Every response includes structuredContent.citations with fields: title, url (ISAP UI), eli, display_address (Dz.U. 2018 poz. 1000), publisher, year, document_type, status, in_force, promulgation.

Patron reads this field automatically and renders it in the UI panel as the section "Polish legal acts (Dz.U. / M.P. - Sejm ELI)".

Stack

• Node 18+ (built-in fetch)
• @modelcontextprotocol/sdk
• Stdio transport
• 500 ms throttle between requests (2 req/s)
• No scraping - pure REST JSON API

Build + run

npm install
npm run build
node dist/index.js

Wiring into Patron

In patron/backend/mcp-servers.json:

{
  "name": "isap",
  "transport": "stdio",
  "command": "node",
  "args": ["C:/Users/<YOUR-USER>/mcp-isap/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":"get_act","arguments":{"eli":"DU/2018/1000"}}}' \
  | node dist/index.js

Should return the Personal Data Protection Act of 10 May 2018, status IN_FORCE, a link to ISAP and a structured citation.

Lineage

API contract derived from legal-data-hunter/sources/PL/DziennikUrzedowy (Python + REST, MIT). TS implementation from scratch - no source code imported.

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-isap (this repo) - Polish legislation (Dz.U. + M.P. via Sejm ELI)
• mcp-saos - common courts, SN, TK, KIO
• mcp-nsa - NSA + 16 WSA administrative courts
• 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.