# mcp-scholaris

An MCP server for retrieving academic papers from open access sources. Provides search across arXiv, Semantic Scholar, and PubMed, with full text retrieval via arXiv PDFs, PubMed Central (BioC API), and Unpaywall. No paywalls, no grey area — legitimate open access only.

## Installation

``````bash
pip install mcp-scholaris
``````

## Tools

### ``search_papers``

Search for academic papers by topic, author, or keyword.

**Parameters:**
- ``query`` (required) — search terms
- ``sources`` (optional) — list of sources to search: ``arxiv``, ``semantic_scholar``, ``pubmed``. Defaults to all three.
- ``max_results`` (optional) — maximum results per source. Defaults to 5.

### ``fetch_paper``

Fetch the full text of a paper. Tries open access sources in order: arXiv → PubMed Central → Unpaywall. Provide at least one identifier.

**Parameters:**
- ``arxiv_id`` — e.g. ``2301.00001`` or ``arxiv:2301.00001``
- ``pubmed_id`` — PubMed ID (PMID), e.g. ``36383508``
- ``doi`` — e.g. ``10.1371/journal.pone.0276755``

## Configuration

Semantic Scholar works without an API key but is rate-limited. For higher limits, create a ``.env`` file in your working directory:

``````
SEMANTIC_SCHOLAR_API_KEY=your_key_here
``````

API keys are free at [semanticscholar.org](https://www.semanticscholar.org/product/api).

## Usage with an MCP client

Add to your MCP client configuration:

``````json
{
  "mcpServers": {
    "scholaris": {
      "command": "scholaris"
    }
  }
}
``````

Or run directly:

``````bash
scholaris
``````

The server communicates over stdio using the MCP protocol (JSON-RPC 2.0).

## Sources

| Source | Search | Full Text |
|---|---|---|
| arXiv | ✓ | ✓ PDF |
| Semantic Scholar | ✓ | ✓ when OA PDF available |
| PubMed | ✓ | ✓ via BioC API (PMC articles) |
| Unpaywall | — | ✓ for any DOI with OA version |

## License

MIT