apaper-mcp

An MCP (Model Context Protocol) server that gives AI assistants direct access to academic paper databases. It exposes a unified set of tools for searching and downloading papers across arXiv, IACR ePrint, DBLP, Google Scholar, and CNKI (中国知网), so an MCP-compatible client (Claude Code, Claude Desktop, or any other) can run literature searches, pull BibTeX entries, and fetch PDFs without leaving the chat.

Tools

arXiv tools scrape the public arxiv.org/search/ HTML page, which works on
networks where the export.arxiv.org Atom API is blocked or rate-limited. If
you need to route through a mirror, set ARXIV_SEARCH_URL,
ARXIV_ADVANCED_URL, and/or ARXIV_PDF_BASE.

The arXiv tools throttle themselves and retry HTTP 429 / 5xx with exponential
backoff, honouring Retry-After; on a persistent block the error names the
throttled IP and wait time. Tune with ARXIV_MIN_INTERVAL_MS (3000),
ARXIV_MAX_RETRIES (3), ARXIV_BACKOFF_BASE_MS (3000),
ARXIV_BACKOFF_MAX_MS (60000), ARXIV_BACKOFF_JITTER_MS (500), and
ARXIV_IP_ECHO_URL ("" to disable the IP lookup).

CNKI tools require institutional access. On IP-based networks the session
cookie is obtained automatically on first use — no manual login needed.

IACR ePrint sits behind Cloudflare, which intermittently serves a JS bot
challenge, most often on PDF downloads. The download tool uses Scrapling's
stealth browser and built-in Cloudflare solver, and only publishes a file after
the response bytes validate as a PDF.

Proxy

Set SPIDER_PROXY to route outbound requests — arXiv, IACR, DBLP, Google
Scholar, and their PDF downloads — through a proxy. CNKI is excluded on purpose:
it authenticates by institutional IP and always uses this host's real address.
Both a standard URL and the colon-delimited form some mobile-proxy providers
hand out are accepted:

SPIDER_PROXY="socks5://user:pass@host:1086"   # standard
SPIDER_PROXY="socks5://host:1086:user:pass"   # host:port:user:pass (e.g. Kookeey)
SPIDER_PROXY="http://user:pass@host:8080"     # HTTP CONNECT proxy

socks5, socks4, http, and https schemes are supported (the scheme
defaults to http when omitted) by the Python runtime. The scheme must match
the proxy's port — a SOCKS port won't accept http:// and vice versa. If
SPIDER_PROXY is set but invalid or can't be initialised, requests are blocked
rather than sent direct, so a misconfigured proxy never leaks this host's real
IP.

Flaky residential/mobile proxies routinely drop or refuse connections;
idempotent (GET) requests through the proxy are retried automatically on such
transient failures. IACR fires the most requests per search (a detail fetch per
result), so its per-request timeouts default high for slow proxies — tune with
IACR_TIMEOUT_MS (30000) and IACR_DOWNLOAD_TIMEOUT_MS (600000). IACR
downloads retry fresh browser sessions three times by default; tune the count
with IACR_CAPTCHA_ATTEMPTS.

Install from PyPI

The maintained runtime requires Python 3.12+. The IACR downloader automatically
uses a chromium executable from PATH. On Arch Linux, install it from the
official repository, then run the published package directly with uvx:

sudo pacman -S chromium
uvx apaper-mcp

On systems without a packaged Chromium, install Scrapling's browser runtime
once with uvx --from 'scrapling[fetchers]' scrapling install. Set
IACR_BROWSER_EXECUTABLE to use a browser at a nonstandard path.

To install the command for repeated use:

uv tool install apaper-mcp
apaper-mcp

For an MCP client, use the published package as the local stdio command:

{
  "mcp": {
    "apaper-mcp": {
      "type": "local",
      "command": ["uvx", "apaper-mcp"],
      "timeout": 900000,
      "enabled": true
    }
  },
  "experimental": {
    "mcp_timeout": 900000
  }
}

The 15-minute timeout is needed for browser-assisted IACR downloads. Some
OpenCode versions ignore the per-server value for tool calls, so the global
experimental.mcp_timeout fallback is included as well. Quit and restart
OpenCode after changing MCP configuration.

Development

Clone the repository and install its development dependencies with uv:

uv sync
uv run apaper-mcp

Install Chromium through your OS package manager. If no system Chromium is
available, run uv run scrapling install instead.

Run tests with uv run pytest.

The Python source uses a standard src package layout. Platform-specific
clients live under src/apaper_mcp/platforms/, while shared server, proxy,
formatter, and model code stays in src/apaper_mcp/.

Local MCP testing

Start the MCP Inspector against the Python stdio server:

npx @modelcontextprotocol/inspector uv run --directory . apaper-mcp

The equivalent module command is:

npx @modelcontextprotocol/inspector \
  uv run --directory . python -m apaper_mcp

To pass the proxy to the inspected server:

npx @modelcontextprotocol/inspector \
  -e SPIDER_PROXY="$SPIDER_PROXY" \
  uv run --directory . apaper-mcp

The Inspector opens a local web UI for listing tools, inspecting schemas, and
calling tools.

Tool schemas

• search_arxiv_papers
  • input: { "query": string, "max_results"?: number, "date_from"?: string, "date_to"?: string, "categories"?: string[], "sort_by"?: "relevance" | "date" }
• download_arxiv_paper
  • input: { "paper_id": string, "save_path"?: string } (paper_id like 2103.12345 or 2103.12345v2)
• search_iacr_papers
  • input: { "query": string, "max_results"?: number, "fetch_details"?: boolean, "year_min"?: number | string, "year_max"?: number | string }
• download_iacr_paper
  • input: { "paper_id": string, "save_path"?: string }
• search_dblp_papers
  • input: { "query": string, "max_results"?: number, "year_from"?: number | string, "year_to"?: number | string, "venue_filter"?: string, "include_bibtex"?: boolean }
• search_google_scholar_papers
  • input: { "query": string, "max_results"?: number, "year_low"?: number | string, "year_high"?: number | string }
• search_cnki_papers
  • input: { "query": string, "page_num"?: number, "page_size"?: number }
• download_cnki_paper
  • input: { "href": string, "save_path"?: string } (use an href from search_cnki_papers)