Paper Download MCP Server

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MCP server for downloading academic papers by DOI, arXiv ID, or URL.

What You Get

• paper_download: Download one or more papers (1-50 per call)

• paper_get_metadata: Get paper metadata without downloading

• Optional PDF-to-Markdown conversion via to_markdown

Quick Start (MCP Clients)

Before configuration, make sure uvx is available:

uvx --version

Claude Code

Add as a project-scoped MCP server:

claude mcp add --transport stdio --scope project --env PAPER_DOWNLOAD_EMAIL=your-email@university.edu paper-download -- uvx paper-download-mcp

This writes .mcp.json in the current project. Equivalent config:

{
  "mcpServers": {
    "paper-download": {
      "command": "uvx",
      "args": ["paper-download-mcp"],
      "env": {
        "PAPER_DOWNLOAD_EMAIL": "your-email@university.edu"
      }
    }
  }
}

Codex

Add with CLI:

codex mcp add paper-download --env PAPER_DOWNLOAD_EMAIL=your-email@university.edu -- uvx paper-download-mcp

Equivalent ~/.codex/config.toml snippet:

[mcp_servers.paper-download]
command = "uvx"
args = ["paper-download-mcp"]

[mcp_servers.paper-download.env]
PAPER_DOWNLOAD_EMAIL = "your-email@university.edu"

Claude Desktop

Edit Claude Desktop MCP config:

• macOS: ~/Library/Application Support/Claude/claude_desktop_config.json

• Windows: %APPDATA%\\Claude\\claude_desktop_config.json

{
  "mcpServers": {
    "paper-download": {
      "command": "uvx",
      "args": ["paper-download-mcp"],
      "env": {
        "PAPER_DOWNLOAD_EMAIL": "your-email@university.edu"
      }
    }
  }
}

Restart Claude Desktop after editing the file.

Configuration

Required

• PAPER_DOWNLOAD_EMAIL: Required for Unpaywall API usage.

Optional (Advanced)

• PAPER_DOWNLOAD_OUTPUT_DIR: Global fallback output directory.

In most cases, you do not need PAPER_DOWNLOAD_OUTPUT_DIR. Prefer passing output_dir in the paper_download tool call when you want a specific location.

Legacy env vars are still supported for compatibility:

• SCIHUB_CLI_EMAIL

• SCIHUB_OUTPUT_DIR

Tools

paper_download

Download papers with configurable concurrency (default parallel=10). If parallel=1, papers are processed sequentially with a 2-second delay between items. OA-first routing uses OpenAlex and Unpaywall first; CORE is disabled by default in MCP runtime.

Parameters:

• identifiers (required): list[str], 1-50 items

• output_dir (optional): target directory (default uses runtime fallback: PAPER_DOWNLOAD_OUTPUT_DIR or ./downloads)

• parallel (optional): concurrent workers, 1-50 (default 10)

• to_markdown (optional): convert PDF to Markdown (false by default)

• md_output_dir (optional): Markdown directory (default <output_dir>/md)

Examples:

paper_download(["10.1038/nature12373"])
paper_download(["10.1038/nature12373", "2301.00001"], output_dir="/path/to/papers")
paper_download(["10.1038/nature12373", "10.1126/science.169.3946.635"], parallel=10)
paper_download(["10.1038/nature12373"], to_markdown=true)

paper_get_metadata

Get metadata quickly (no PDF download).

Parameters:

• identifier (required): DOI, arXiv ID, or URL

Example:

paper_get_metadata("10.1038/nature12373")

Troubleshooting

PAPER_DOWNLOAD_EMAIL environment variable is required

Set PAPER_DOWNLOAD_EMAIL in your MCP server config.

uvx: command not found

Install uv, then re-run the MCP configuration.

Download path errors

Pass a writable directory with output_dir, for example:

paper_download(["10.1038/nature12373"], output_dir="/absolute/path")

Legal Notice

This tool can access papers from multiple sources, including Unpaywall and Sci-Hub. You are responsible for complying with copyright and local laws in your jurisdiction.

License

MIT. See LICENSE.