Model Context Protocol

Cite anything, from your AI agent.

Citation API is an MCP server. Connect it to Claude, Cursor, or any MCP client and your agent can generate accurate citations and full bibliographies on demand — using the same API key you already have.

Get Free API Key Setup in 30 seconds

Four tools

Everything an agent needs to cite sources and build a bibliography.

cite_url

Turn any URL — article, journal, book, video, repo — into a citation with CSL-JSON and formatted strings.

cite_identifier

Cite directly from a DOI, ISBN, PMID, or PMC ID. Fast, high-accuracy resolution from authoritative sources.

cite_batch

Cite up to 50 URLs in a single call — ideal for an agent assembling an entire bibliography.

format_citation

Render an existing CSL-JSON item into APA, MLA, Chicago, or BibTeX. No extraction, no network.

Set up in seconds

Point your MCP client at the endpoint and authenticate with your API key as a bearer token. No new credentials, no OAuth dance.

Claude Code (CLI)

bash

claude mcp add --transport http citation \
  https://api.citationapi.com/mcp \
  --header "Authorization: Bearer YOUR_API_KEY"

Generic MCP client (JSON)

json

{
  "mcpServers": {
    "citation": {
      "type": "http",
      "url": "https://api.citationapi.com/mcp",
      "headers": {
        "Authorization": "Bearer YOUR_API_KEY"
      }
    }
  }
}

Then just ask

text

You: Cite https://www.nature.com/articles/d41586-024-00001-2 in APA.

Agent → cite_url({ url: "...", styles: ["apa"] })
     → "Author, A. (2024). Title. Nature. https://doi.org/..."

Your existing key

Authenticate with the same API key as the REST API. Per-key rate limits and plan quotas apply.

Same engine

Backed by the same 4-layer pipeline — Crossref, PubMed, OpenLibrary, and more — and 9,000+ styles.

Built for agents

Batch citations, structured CSL-JSON output, and cached results keep agent workflows fast.

Give your agent citations

Grab a free API key, add the MCP server, and start citing. No credit card required.

Get Free API Key