Scholar Sidekick

MCP server for Scholar Sidekick — resolve any scholarly identifier (DOI, PMID, PMCID, ISBN, arXiv, ISSN, NASA ADS bibcode, WHO IRIS URL) into 10,000+ CSL styles or nine export formats, plus retraction, open-access, and citation-fabrication-detection checks, from any AI assistant.

Highlights

• Eight identifier types out of the box — DOIs, PMIDs, PMCIDs, ISBNs, arXiv IDs, ISSNs, NASA ADS bibcodes, and WHO IRIS URLs (rare in citation tooling).
• Batch-friendly resolve / format / export — each accepts a single identifier or a comma- or newline-separated list; the server normalises the list and resolves them in one round trip.
• 10,000+ citation styles — five hand-tuned builtins (Vancouver, AMA, APA, IEEE, CSE) plus any CSL style ID, with alias and dependent-style resolution.
• Nine export formats — BibTeX, RIS, CSL JSON, EndNote (XML/Refer), RefWorks, MEDLINE, Zotero RDF, CSV, plain text.
• Retraction & open-access checks — checkRetraction surfaces retractions, corrections, and expressions of concern (Crossref / Retraction Watch); checkOpenAccess returns OA status and the best legal landing or PDF URL (Unpaywall). Both accept any identifier type and resolve it to a DOI under the hood.
• Citation-fabrication detection — verifyCitation cross-checks a claimed citation against the resolved record at its identifier, detecting the dominant AI-driven fabrication pattern documented by Topaz et al. (Lancet 2026) — real DOI + invented title — that simple identifier resolution cannot catch. Long-form explainer at scholar-sidekick.com/citation-integrity.
• Composable workflow — chain resolveIdentifier → formatCitation → exportCitation in one prompt for an end-to-end "raw IDs → exportable bibliography" pipeline.
• Provenance metadata on every response — formatted output is followed by a metadata block (requestId, formatter, styleUsed, warnings) so the assistant can show users which engine produced each citation.
• No key required — works anonymously against the public Scholar Sidekick API (rate-limited free tier); add a free first-party ssk_ key for higher limits, or a RapidAPI key for paid/managed tiers.
• Hosted HTTP endpoint (no install) — prefer not to run a local stdio server? Connect any HTTP-capable MCP client straight to https://scholar-sidekick.com/api/mcp (Streamable HTTP, same 6 tools). See Hosted HTTP endpoint.
• REST API twin — the same endpoints are available as the Scholar Sidekick REST API for non-MCP integrations.

Tools

Tool	Description
resolveIdentifier	Resolve DOIs, PMIDs, PMCIDs, ISBNs, arXiv IDs, ISSNs, ADS bibcodes, and WHO IRIS URLs to structured bibliographic metadata (CSL JSON). Accepts a single identifier or a comma/newline-separated batch.
formatCitation	Format one or many identifiers into Vancouver, AMA, APA, IEEE, CSE, or any of 10,000+ CSL styles. Output as text, HTML, or JSON. Returns formatted citations plus a provenance metadata block.
exportCitation	Export one or many identifiers to BibTeX, RIS, CSL JSON, EndNote (XML/Refer), RefWorks, MEDLINE, Zotero RDF, CSV, or plain text — ready to write to disk or hand to a reference manager.
checkRetraction	Check whether a single work has been retracted, corrected, or had an expression of concern raised. Sourced from Crossref updated-by (Retraction Watch). Resolves DOI/PMID/PMCID/arXiv/ADS inputs to a DOI before lookup. One identifier per call.
checkOpenAccess	Check whether a single work is openly accessible and where to find the best legal version. Sourced from Unpaywall. Returns OA status (gold/green/hybrid/bronze/closed), best landing/PDF URL, license, and version. Resolves DOI/PMID/PMCID/arXiv/ISBN/ADS inputs to a DOI before lookup. One identifier per call.
verifyCitation	Verify a claimed citation against the resolved record at its identifier. Detects the Topaz et al. (Lancet 2026) fabrication pattern — real DOI + invented title — that resolveIdentifier alone cannot catch. Returns one of four verdicts (matched / mismatch / ambiguous / not_found) plus per-field similarity scores and the resolved record so the user can see where the cited title and the actual paper diverged. Optional Stage 3 LLM screen rescues informal-abbreviation false positives (paid plans / first-party authentication only). One citation per call.

Setup

No key required. The server works anonymously against the public Scholar Sidekick API (https://scholar-sidekick.com) at a rate-limited free tier — just install and go. To raise your limits, create a free first-party ssk_ key at scholar-sidekick.com/account and set SCHOLAR_API_KEY. For paid/managed tiers, subscribe on RapidAPI and set RAPIDAPI_KEY (which routes calls through the RapidAPI gateway).

Prefer zero install? There's also a hosted HTTP endpoint at https://scholar-sidekick.com/api/mcp (Streamable HTTP) — connect any HTTP-capable MCP client directly, no npx needed. See Hosted HTTP endpoint below. The stdio package documented here is the local-install alternative (and the path for RapidAPI-keyed users).

Claude Desktop

Add to ~/Library/Application Support/Claude/claude_desktop_config.json (macOS) or %APPDATA%\Claude\claude_desktop_config.json (Windows). The env block is optional — omit it to run anonymously:

{
  "mcpServers": {
    "scholar-sidekick": {
      "command": "npx",
      "args": ["-y", "scholar-sidekick-mcp@latest"],
      "env": {
        "SCHOLAR_API_KEY": "ssk_your-first-party-key"
      }
    }
  }
}

Claude Code

# Anonymous (no key):
claude mcp add scholar-sidekick -- npx -y scholar-sidekick-mcp@latest

# With a free first-party key for higher limits:
claude mcp add scholar-sidekick \
  -e SCHOLAR_API_KEY=ssk_your-first-party-key \
  -- npx -y scholar-sidekick-mcp@latest

Cursor / VS Code / Windsurf

Add to .cursor/mcp.json or .vscode/mcp.json (the env block is optional):

{
  "mcpServers": {
    "scholar-sidekick": {
      "command": "npx",
      "args": ["-y", "scholar-sidekick-mcp@latest"],
      "env": {
        "SCHOLAR_API_KEY": "ssk_your-first-party-key"
      }
    }
  }
}

Agent skill (optional)

Install a companion Agent Skill that teaches Claude Code, Cline, and other agents when and how to use these tools — it complements the server config above:

npx skills add mlava/scholar-sidekick-mcp

Hosted HTTP endpoint (no install)

Don't want to run a local stdio server? Scholar Sidekick is also a hosted Streamable HTTP MCP at https://scholar-sidekick.com/api/mcp — the same six tools, no npx, no local process. It works anonymously (rate-limited free tier); add an Authorization: Bearer ssk_… header (a free key from scholar-sidekick.com/account) for higher limits.

Point any HTTP-capable MCP client at it:

{
  "mcpServers": {
    "scholar-sidekick": {
      "type": "http",
      "url": "https://scholar-sidekick.com/api/mcp"
    }
  }
}

In Claude Desktop, use Settings → Connectors → Add custom connector (or "Add HTTP server") and paste the URL. Add the bearer token in the client's header/auth field if you have one.

Discovery: /.well-known/mcp.json (SEP-1649 server card) lists this endpoint plus the no-auth ChatGPT Apps endpoint at /api/apps/mcp. The stdio package above remains the local-install alternative and the path for RapidAPI-keyed users.

Environment Variables

Variable	Required	Description
SCHOLAR_API_KEY	No	Free first-party ssk_ key from scholar-sidekick.com/account; raises rate limits and enables the verifier's LLM screen. Sent as Authorization: Bearer.
RAPIDAPI_KEY	No	RapidAPI subscription key for paid/managed tiers; when set, calls route through the RapidAPI gateway.
RAPIDAPI_HOST	No	RapidAPI host (defaults to scholar-sidekick.p.rapidapi.com)
SCHOLAR_SIDEKICK_URL	No	Override the API base URL (defaults to https://scholar-sidekick.com, or the RapidAPI gateway when RAPIDAPI_KEY is set).
SCHOLAR_SIDEKICK_TIMEOUT_MS	No	Request timeout in milliseconds (default: 30000)

No key at all → anonymous, rate-limited free tier. With both SCHOLAR_API_KEY and RAPIDAPI_KEY set, RapidAPI takes precedence.

Supported Citation Styles

Scholar Sidekick supports 10,000+ CSL styles, including all major formats used in academic publishing:

Style	Keyword
Vancouver	vancouver
APA (7th ed.)	apa
AMA	ama
IEEE	ieee
CSE	cse
Chicago (author-date)	chicago-author-date
Harvard	harvard-cite-them-right
MLA	modern-language-association
Turabian	turabian-fullnote-bibliography
Nature	nature
BMJ	bmj
Lancet	the-lancet

Any CSL style ID can be passed as the style parameter.

Example Usage

Once connected, ask your AI assistant:

Single identifier

• "Format 10.1056/NEJMoa2033700 in Vancouver style"
• "Resolve PMID:30049270 and export as BibTeX"
• "Give me a Chicago citation for arXiv:2301.08745"

Batch input (comma- or newline-separated — every tool handles it)

• "Format these as APA: 10.1056/NEJMoa2033700, PMID:30049270, ISBN:9780192854087"
• "Resolve all of these and tell me which are journal articles vs books: 10.1056/NEJMoa2033700, ISBN:9780192854087, PMC7793608"

End-to-end workflow (the assistant chains resolveIdentifier → formatCitation → exportCitation in one prompt)

• "Resolve these three identifiers, format each in AMA, and export the set as BibTeX: 10.1056/NEJMoa2033700, PMID:30049270, ISBN:9780192854087"
• "Build me a Nature-style bibliography from this list and give me a .bib file at the end: PMID:30049270, arXiv:2301.08745, 10.1038/s41586-021-03819-2"

Retraction & open-access checks (one identifier per call)

• "Has 10.1016/S0140-6736(20)31180-6 been retracted?" → returns isRetracted: true with the retraction notice and date
• "Is the NumPy paper (10.1038/s41586-020-2649-2) open access? Where can I read it for free?" → returns OA status plus the best legal PDF URL with license and version
• "Check whether arXiv:2301.08745 has any corrections or expressions of concern." → resolves arXiv → DOI, then queries Retraction Watch

Supported Identifiers

• DOIs (e.g. 10.1056/NEJMoa2033700)
• PubMed IDs (e.g. PMID:30049270)
• PubMed Central IDs (e.g. PMC7793608)
• ISBNs (e.g. ISBN:9780192854087)
• arXiv IDs (e.g. 2301.08745)
• ISSNs and eISSNs
• NASA ADS bibcodes
• WHO IRIS URLs

Provenance & Determinism

Every formatCitation and exportCitation response is followed by a metadata block so the assistant — and the user — can see exactly which engine produced each citation:

• formatter — builtin (one of Vancouver, AMA, APA, IEEE, CSE — hand-tuned in TypeScript) or csl (citeproc-js with a CSL stylesheet).
• styleUsed — the canonical style ID after alias and dependent-style resolution (e.g. asking for harvard resolves to harvard-cite-them-right).
• requestId — for support, reproducibility, and log correlation.
• warnings — populated when a fallback was used or the requested style was a dependent of another.

Identifier resolution is deterministic given the same inputs and pinned upstream metadata. Repeated identical requests are cache-hit on the underlying REST API and surface that via the x-scholar-cache header.

REST API

For programmatic access outside of MCP clients, the same capabilities are available as a REST API at scholar-sidekick.com — anonymously, with a free first-party ssk_ key (Authorization: Bearer), or via RapidAPI for paid tiers. Whichever credential you use here works there too.

Development

npm install
npm run build    # Bundle to dist/mcp-server.mjs
npm test         # Run tests
npm run typecheck

License

MIT

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