NASA SciX MCP Server

A Model Context Protocol (MCP) server for the NASA Astrophysics Data System (SciX) API. This server enables LLMs to search astronomical literature, retrieve paper metadata, analyze citation metrics, and export bibliographic data.

Quick Start (MCP clients)

Get an API Key

1. Create an account at SciX
2. Generate an API token at https://scixplorer.org/user/settings/token
3. Set the environment variable:

export SCIX_API_TOKEN=your_api_key_here

Or create a .env file:

cp .env.example .env
# Edit .env and add your key

Configure your MCP client (Claude, Codex, etc.)

Add to your MCP client configuration:

{
  "mcpServers": {
    "ads": {
      "command": "npx",
      "args": ["scix-mcp"],
      "env": {
        "SCIX_API_TOKEN": "your_api_key_here"
      }
    }
  }
}

Common locations: Claude Desktop (~/Library/Application Support/Claude/claude_desktop_config.json on macOS or %AppData%\\Claude\\claude_desktop_config.json on Windows) and Codex CLI (~/.config/codex/config.json). Restart your client after editing.

Local MCP clients that read .mcp/server.json can also pick up the packaged config in .mcp/server.json; just drop in your SCIX_API_TOKEN.

Example Prompts

- Find refereed JWST exoplanet papers from 2022-2024 sorted by citation_count, return the top 5 in markdown with bibcodes, titles, first author, and citation counts.
- Build a query for gravitational wave kilonova follow-ups since 2017 (fielded abstract search), add the first 50 results to library <library_id>, and then give me metrics (h-index, total cites) for those bibcodes in JSON.
- Fetch paper 2020ApJ...905....3A, list its first 10 references with titles, and also list the first 10 forward citations with publication years.
- Create a public library named “Cosmic Web Reviews”, seeded with bibcodes [...], then share the public URL and export the contents in BibTeX.
- For bibcodes [...], return citation metrics plus a ranked list of which papers cite the most recent one (rows=25) in markdown.
- Get all my libraries, pick the one with the most documents, and return its metadata plus the first 5 document titles in JSON.

Features

• Literature Search: Full-text search with advanced Solr query syntax
• Paper Details: Retrieve comprehensive metadata for any publication
• Citation Metrics: Calculate h-index, citation counts, and usage statistics
• Citation Network: Explore forward and backward citations
• Export: Generate citations in BibTeX, AASTeX, EndNote, and MEDLARS formats
• Documentation Search: Query SciX help/docs content via the search_docs tool
• Dual Format: Support for both human-readable Markdown and machine-readable JSON

Available Tools

Search & Metadata

• search: Solr-powered search across SciX. Params: query (required), rows (1-100, default 10), start (offset, default 0), sort (score desc | citation_count desc | date desc | date asc | read_count desc, default score desc), response_format (markdown | json, default markdown).
  • Example queries: author:"Einstein, A." title:relativity, black holes year:2020-2023, author:^Smith, dark energy AND galaxy clusters.
• get_paper: Fetch a paper by bibcode with optional response_format.
• get_metrics: Metrics for bibcodes (1-2000) with optional response_format; returns h-index, g-index, citation counts, usage stats.

Citation Network

• get_citations: Forward citations for bibcode; optional rows (1-100, default 20) and response_format.
• get_references: Backward references for bibcode; optional rows (1-100, default 20) and response_format.

Export

• export: Export bibcodes (1-2000) in format (bibtex | aastex | endnote | medlars). Returns plain text in the chosen format.

Documentation

• search_docs: Search SciX help documentation. Params: query (required, natural language), limit (1-20, default 5). Returns a ranked list with title, section/subsection, source URL, relevance score, and a focused snippet.

Libraries

• get_libraries: List libraries; optional type (all | owner | collaborator, default all) and response_format.
• get_library: Metadata + documents for library_id; optional response_format.
• create_library: Create with name (required), optional description, public (default false), bibcodes, and response_format.
• delete_library: Permanently delete by library_id; optional response_format.
• edit_library: Update name, description, or public for library_id; optional response_format.
• manage_documents: Add/remove documents with library_id, bibcodes (1-2000), action (add | remove), and optional response_format.
• add_documents_by_query: Add search results to a library with library_id, query, optional rows (1-2000, default 25), and response_format.
• library_operation: Run set ops on a library with library_id, operation (union | intersection | difference | copy | empty), optional source_library_ids, name/description (for copy), and response_format.

Permissions & Sharing

• get_permissions: View owners/collaborators for library_id; optional response_format.
• update_permissions: Grant/change a user's access with library_id, email, permission (owner | admin | write | read), and optional response_format.
• transfer_library: Transfer ownership with library_id, email, and optional response_format.

Annotations

• get_annotation: Fetch note content for library_id + bibcode; optional response_format.
• manage_annotation: Add/update note with library_id, bibcode, content, and optional response_format.
• delete_annotation: Remove note for library_id + bibcode; optional response_format.

Rate Limits

• 5000 requests per day per API key
• Rate limit info is returned in response headers
• Contact adshelp@cfa.harvard.edu for higher limits

SciX Search Syntax

The SciX search supports powerful query syntax:

Syntax	Description	Example
author:"Last, F."	Exact author	author:"Huchra, John"
author:^Last	First author	author:^Smith
title:keyword	Title search	title:exoplanet
abstract:keyword	Abstract search	abstract:"dark matter"
year:YYYY-YYYY	Year range	year:2020-2023
property:refereed	Refereed only	property:refereed
citations(bibcode:X)	Papers citing X	citations(bibcode:2019ApJ...)
references(bibcode:X)	Papers cited by X	references(bibcode:2019ApJ...)
AND, OR, NOT	Boolean operators	black holes AND galaxy

Development

Install & Build

npm install
npm run build

Local commands

# Watch mode
npm run dev

# Test with MCP Inspector
npx @modelcontextprotocol/inspector node build/index.js

Testing

The project includes a comprehensive test suite using Vitest.

Running Tests

# Run all tests
pnpm test

# Run tests in watch mode
pnpm test:watch

# Run tests with coverage
pnpm test:coverage

Test Structure

Tests are organized in the test/ directory:

test/
├── helpers/
│   └── mockFetch.ts        # Fetch mocking utilities
├── client.test.ts          # HTTP client tests
├── search-docs.test.ts     # Documentation search tests
└── tools/
    ├── search.test.ts      # Search tool tests
    ├── paper.test.ts       # Paper details tests
    ├── metrics.test.ts     # Metrics tests
    ├── citations.test.ts   # Citations/references tests
    ├── export.test.ts      # Export tests
    └── library.test.ts     # Library management tests

Test Coverage

The test suite covers:

• HTTP Client: GET/POST/PUT/DELETE methods, error handling (401/404/429), timeouts, request formatting
• Search Tools: Query parameter encoding, pagination, result limiting, response formatting
• Paper Tools: Bibcode validation, field selection, error handling for missing papers
• Metrics Tools: Batch bibcode processing, MAX_BIBCODES limits, metric type selection
• Citation Tools: Forward/backward citations, sorting, row limits
• Export Tools: Multiple export formats (BibTeX, AASTeX, EndNote, etc.), batch processing
• Library Tools: All CRUD operations, permissions, annotations, library operations

API Token for Tests

Tests use mock fetch and don't require a real API token. The test suite sets ADS_DEV_KEY=test-api-key automatically.

Live Integration Tests (Optional)

To run tests against the real ADS API (skipped by default):

1. Set your real API key:

   export SCIX_API_TOKEN=your_real_api_key
   

2. Run integration tests (not implemented yet):

   pnpm test:integration
   

Note: Integration tests count against your daily rate limit (5000 requests/day).

Project Structure

src/
├── index.ts          # Main server entry point
├── client.ts         # SciX API client wrapper
├── types.ts          # TypeScript/Zod type definitions
├── formatters.ts     # Response formatting utilities
├── config.ts         # Configuration constants
└── tools/
    ├── search.ts     # Search tool
    ├── paper.ts      # Paper details tool
    ├── metrics.ts    # Metrics tool
    ├── citations.ts  # Citation network tools
    └── export.ts     # Export tool

Library tools

• get_libraries / get_library: List and inspect libraries
• create_library / delete_library / edit_library: Manage library metadata
• manage_documents: Add/remove bibcodes to a library
• add_documents_by_query: Add results from a search query to a library
• library_operation: Union/intersection/difference/copy/empty on libraries
• get_permissions / update_permissions / transfer_library: Manage sharing
• get_annotation / manage_annotation / delete_annotation: Handle notes on documents

Example Usage

Search for papers

Use search with query "supernova 2023" to find recent supernova papers

Get paper details

Use get_paper with bibcode "2023ApJ...950..123S"

Calculate metrics

Use get_metrics with bibcodes ["2023ApJ...950..123S", "2022MNRAS.517.1234T"]

Export citations

Use export with bibcodes ["2023ApJ...950..123S"] and format "bibtex"

Error Handling

The server provides clear error messages:

• 401: Invalid API key - check SCIX_API_TOKEN
• 404: Resource not found - check bibcode format
• 429: Rate limit exceeded - wait until reset
• Timeout: Request took > 30 seconds

Resources

• SciX Homepage
• SciX API Documentation
• SciX Search Syntax
• MCP Documentation

License

MIT

Support

For API issues: adshelp@cfa.harvard.edu For server issues: Open an issue on GitHub