format_citation

Instructions

Implementation Reference

• src/tools/format-citation.ts:21-49 (handler)

  The registerTool function that registers and implements the 'format_citation' tool. It takes a DOI and optional style/locale, normalizes the DOI, builds an appropriate Accept header, fetches the citation from doi.org, and returns the formatted citation as JSON.

  export function registerTool(server: McpServer): void {
    server.tool(
      "format_citation",
      "Format a DOI as a citation string. Supports APA, MLA, Chicago, Harvard, IEEE, Vancouver, BibTeX, and CSL JSON styles.",
      FormatCitationSchema.shape,
      async (params) => {
        const input = FormatCitationSchema.parse(params);
        const doi = normalizeDoi(input.doi);
        const accept = getAcceptHeader(input.style, input.locale);
        const url = `https://doi.org/${doi}`;
  
        try {
          const citation = await dataciteClient.getText(url, accept);
  
          return {
            content: [
              {
                type: "text" as const,
                text: JSON.stringify({ citation: citation.trim(), style: input.style, doi }, null, 2),
              },
            ],
          };
        } catch (err) {
          const msg = err instanceof Error ? err.message : String(err);
          throw apiError(msg);
        }
      }
    );
  }

• src/tools/format-citation.ts:7-13 (schema)

  Zod schema defining the input for format_citation: doi (required string), style (enum with default 'apa'), and locale (string, default 'en-US').

  const FormatCitationSchema = z.object({
    doi: z.string().min(1),
    style: z
      .enum(["apa", "mla", "chicago", "harvard", "ieee", "vancouver", "bibtex", "citeproc-json"])
      .default("apa"),
    locale: z.string().default("en-US"),
  });

• src/tools/index.ts:4-15 (registration)

  Import and registration of format_citation in the central tool registration index.

  import { registerTool as registerFormatCitation } from "./format-citation.js";
  import { registerTool as registerGetDoiMetrics } from "./get-doi-metrics.js";
  import { registerTool as registerGetRelatedWorks } from "./get-related-works.js";
  import { registerTool as registerSearchByPerson } from "./search-by-person.js";
  import { registerTool as registerListRepositories } from "./list-repositories.js";
  import { registerTool as registerGetRepository } from "./get-repository.js";
  import { registerTool as registerGetDoiSchemaXml } from "./get-doi-schema-xml.js";
  
  export function registerAllTools(server: McpServer): void {
    registerSearchDois(server);
    registerGetDoi(server);
    registerFormatCitation(server);

• src/tools/format-citation.ts:15-19 (helper)

  Helper function getAcceptHeader that maps style names to HTTP Accept headers (e.g., bibtex -> application/x-bibtex, citeproc-json -> application/vnd.citationstyles.csl+json, or text/x-bibliography with style/locale parameters).

  function getAcceptHeader(style: string, locale: string): string {
    if (style === "bibtex") return "application/x-bibtex";
    if (style === "citeproc-json") return "application/vnd.citationstyles.csl+json";
    return `text/x-bibliography; style=${style}; locale=${locale}`;
  }

• src/datacite/doi-normalizer.ts:11-34 (helper)

  Helper function normalizeDoi that strips URL/DOI prefixes and lowercases the prefix portion.

  export function normalizeDoi(input: string): string {
    let doi = input.trim();
  
    // Strip URL prefixes
    if (doi.toLowerCase().startsWith("https://doi.org/")) {
      doi = doi.slice("https://doi.org/".length);
    } else if (doi.toLowerCase().startsWith("http://doi.org/")) {
      doi = doi.slice("http://doi.org/".length);
    } else if (doi.toLowerCase().startsWith("doi:")) {
      doi = doi.slice("doi:".length);
    }
  
    // Lowercase only the prefix (registrant prefix, e.g. "10.5061")
    const slashIndex = doi.indexOf("/");
    if (slashIndex !== -1) {
      const prefix = doi.slice(0, slashIndex).toLowerCase();
      const suffix = doi.slice(slashIndex + 1);
      doi = `${prefix}/${suffix}`;
    } else {
      doi = doi.toLowerCase();
    }
  
    return doi;
  }