Unpaywall

Polski

Unpaywall Open Access scholarly API MCP server. Looks up free-to-read versions of papers by DOI and searches article titles for OA matches.

Table of contents

• Tools
• Environment variables
• Wiring it up
• Local run

Tools

Tool	Parameters	Description
get_doi	doi: str	OA status + bibliographic metadata for a single DOI
search_articles	query: str, is_oa: Optional[bool] = None, page: int = 1	Search article titles; returns up to 50 DOI objects per page

search_articles query modifiers: "quoted phrase" (contiguous), OR (either term), -term (exclude). is_oa tri-state: None no filter, True OA only, False non-OA only.

Environment variables

Variable	Required	Description
UNPAYWALL_MCP_EMAIL	yes	Contact email Unpaywall requires on every request

Unpaywall rate limit: 100,000 calls/day per email.

Wiring it up

Only requirement: uv (https://docs.astral.sh/uv/). Nothing else to install.

Claude Code

claude mcp add unpaywall-mcp -e UNPAYWALL_MCP_EMAIL=<your-email> -- uvx --from git+https://github.com/dam2452/unpaywall-mcp.git unpaywall-mcp

Claude Desktop / other MCP client

{
  "mcpServers": {
    "unpaywall-mcp": {
      "command": "uvx",
      "args": ["--from", "git+https://github.com/dam2452/unpaywall-mcp.git", "unpaywall-mcp"],
      "env": { "UNPAYWALL_MCP_EMAIL": "<your-email>" }
    }
  }
}

After pushing a new version: uv cache clean and restart the client.

Local run

uv run --directory . unpaywall-mcp

Tests (manual):

uv run --directory . --with pytest pytest test/