Nccn MCP Server

nccn-mcp-server

An MCP (Model Context Protocol) server that provides access to NCCN (National Comprehensive Cancer Network) clinical cancer treatment guidelines. Ported from the Python NCCN_guidelines_MCP project.

Built on somamcp (MCP framework) and functype (FP patterns). Uses a non-RAG approach — reads guidelines directly from PDFs for accuracy and traceability.

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⚠️ Licensing Notice — Read Before Use

NCCN content is copyrighted and its End-User License Agreement explicitly prohibits AI use without a separate written agreement with NCCN.

The relevant EULA clause states:

"Except as otherwise separately and specifically agreed in writing by NCCN, users shall not use NCCN Content in connection with any development, testing, training, exploitation or support of any artificial intelligence (AI) software or other model, algorithm or technology."

This project is provided for personal research and evaluation only. Do not deploy it in any commercial, clinical, or client-facing context without first obtaining an NCCN license. Contact [[email protected]](mailto:[email protected]) for licensing inquiries.

Regulatory context

• NCCN is recognized by CMS (not FDA) as an authoritative compendium under Social Security Act §1861(t)(2)(B) for Medicare coverage determinations of off-label anti-cancer drug indications.
• FDA has no rule that overrides NCCN's copyright or licensing terms. The EULA restriction on AI use is a private contract term, not a regulatory question.
• For production AI integrations that need NCCN content, consider either (a) a direct NCCN license (the path OpenEvidence took in Nov 2025) or (b) integrating via a licensed aggregator like OpenEvidence's API.

No warranty

This software is provided "as is" without warranty of any kind. It does not constitute medical advice, is not a clinical decision support tool, and must not be used as the sole basis for any treatment decision.

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Features

• Live index — scrapes the NCCN site to discover all available guidelines across 4 categories (Treatment by Cancer Type, Detection/Prevention, Supportive Care, Specific Populations), ~90 guidelines total. Each entry carries the current Version X.YYYY string from NCCN.
• Version-aware PDF caching — per-file .meta.json sidecar tracks NCCN's live version string; re-downloads only when NCCN actually publishes a new version, with a 6h throttle on version checks and a 30-day hard refresh ceiling.
• Authenticated PDF download — detects NCCN's login redirect, authenticates with credentials, and retries with auth cookies.
• Per-page text extraction — pulls text from specific pages or ranges, supports negative indexing for last page.
• File-based caching — 7-day default TTL for both the YAML index and downloaded PDFs, with stale-cache fallback if scraping fails.
• Functional error handling — all I/O operations return Either<Error, T> via functype.

MCP Tools

Tool	Purpose	Key Parameters
get_index	List all available guidelines organized by category (includes live version + detailUrl)	(none)
download_pdf	Download a guideline PDF with version-aware caching (auto-login, 6h throttle, 30d hard refresh)	url, optional username/password, optional force_refresh
extract_content	Extract text from specific pages of a downloaded PDF	pdf_path, optional pages

Resources

Resource URI	Purpose
nccn://guidelines-index	Full YAML index of all guidelines and categories

Page specification syntax (for extract_content)

• Single: "3"
• Multiple: "1,3,5"
• Range: "1-5"
• Combined: "1,3,5-7"
• Last page: "-1"
• Omit entirely to extract all pages

Typical Agent Workflow

1. Call get_index — find a guideline URL by cancer type
2. Call download_pdf(url) — returns a local PDF path under ./downloads/
3. Call extract_content(pdf_path, "3") — read the Table of Contents (page 3 is standard for NCCN guidelines)
4. Call extract_content(pdf_path, "10-15") — read specific clinical pages
5. Provide evidence-based answer with page citations

Installation

pnpm install
pnpm build

Configuration

Environment variables

Variable	Purpose	Required
NCCN_USERNAME	NCCN account email for PDF login	Yes for downloads (or passed as tool arg)
NCCN_PASSWORD	NCCN account password	Yes for downloads (or passed as tool arg)
MCP_TRANSPORT	stdio (default) or httpStream	No
MCP_PORT	Port for httpStream transport (default 8000)	No

Claude Code integration (.mcp.json)

{
  "mcpServers": {
    "nccn-guidelines": {
      "command": "node",
      "args": ["dist/index.js"],
      "env": {
        "NCCN_USERNAME": "${NCCN_USERNAME}",
        "NCCN_PASSWORD": "${NCCN_PASSWORD}"
      }
    }
  }
}

Place this at the repo root and Claude Code will prompt to approve the project-scoped server on next restart.

Usage

As an MCP server (stdio — default)

pnpm start

HTTP stream transport

MCP_TRANSPORT=httpStream MCP_PORT=8000 pnpm start

Architecture

Entry point (src/index.ts)

Creates the MCP server via somamcp.createServer() and registers 3 tools + 1 resource. On startup, kicks off an async index refresh (non-blocking), then starts the configured transport.

Modules

Module	Responsibility
src/scraper/index-scraper.ts	Scrapes NCCN (4 category pages + each guideline detail page) using cheerio. Returns Either<Error, GuidelineIndex>. Cached 7 days.
src/downloader/pdf-downloader.ts	Downloads PDFs with NCCN login flow. Detects login redirects, authenticates with NCCN_USERNAME/NCCN_PASSWORD, retries with auth cookies.
src/reader/pdf-reader.ts	Extracts per-page text via pdf-parse's pagerender callback. Supports page specs and negative indexing.
src/cache/cache.ts	File-based caching for the YAML index and PDF files. Uses functype's Option/Either.
src/types.ts	Shared types and constants (cache durations, URLs, User-Agent).

Cache behavior

• Index: ./nccn_guidelines_index.yaml (7-day TTL). Stale cache is returned as a fallback when scraping fails.
• PDFs: ./downloads/*.pdf with per-file metadata sidecar *.meta.json tracking the live NCCN version string and last-checked timestamp.
• Version-aware refresh policy on download_pdf:
  1. force_refresh=true → always re-download.
  2. Cached file older than 30 days → re-download (catches silent revisions NCCN may ship without bumping the version string).
  3. Within 6 hours of last check → trust cache, no network call.
  4. Otherwise → fetch the detail page, compare Version X.YYYY, re-download only if changed.

Development

pnpm validate                                    # format + lint + typecheck + test + build
pnpm test                                        # run tests once
pnpm vitest run test/reader/pdf-reader.spec.ts   # run a single test file
pnpm build                                       # production build
pnpm dev                                         # watch mode
pnpm typecheck                                   # type checking only
pnpm start                                       # run the built server (stdio transport)

Project Structure

src/
├── cache/              # YAML + PDF caching
├── downloader/         # PDF download with NCCN auth flow
├── reader/             # Per-page PDF text extraction
├── scraper/            # NCCN website scraper
├── types.ts            # Shared types and constants
└── index.ts            # MCP server entry point
test/                   # Vitest specs mirroring src/ layout
dist/                   # Built output (ES module + types)
downloads/              # Downloaded PDFs (gitignored)
nccn_guidelines_index.yaml  # Cached index (gitignored)

Dependencies

• somamcp — MCP framework
• functype — Option/Either/Try
• cheerio — HTML parsing (replaces Python BeautifulSoup)
• pdf-parse — PDF text extraction (replaces Python pypdf)
• js-yaml — YAML read/write
• zod — Tool parameter schemas
• dotenv — .env file loading

License

MIT (for this codebase). See the Licensing Notice above for NCCN content usage restrictions — the MIT license on this code does not grant any rights to NCCN content.