Paper Citation & Reference Lookup (by DOI, arXiv ID, or PMID)

{
  "type": "object",
  "anyOf": [
    {
      "required": [
        "id"
      ]
    },
    {
      "required": [
        "doi"
      ]
    }
  ],
  "properties": {
    "id": {
      "type": "string",
      "description": "arXiv id, DOI, OpenAlex id, or PMID"
    },
    "doi": {
      "type": "string",
      "description": "alias for id (DOI form)"
    },
    "ref_limit": {
      "type": "string",
      "default": "25",
      "description": "max references (0-100)"
    },
    "cite_limit": {
      "type": "string",
      "default": "25",
      "description": "max citing works (0-100)"
    }
  },
  "additionalProperties": false
}

{
  "type": "object",
  "properties": {
    "code": {
      "type": "string",
      "description": "Present instead of `count`/`items` when the id/DOI does not resolve to a known paper. Observed as the literal string 'HTTP_400' on the one such fixture captured."
    },
    "count": {
      "type": "number",
      "description": "Number of entries in `items`; 1 on the successful fixture observed."
    },
    "items": {
      "type": "array",
      "items": {
        "type": "object",
        "properties": {
          "doi": {
            "type": [
              "string",
              "null"
            ],
            "description": "The paper's own DOI. Observed null on the one real fixture captured (an arXiv preprint with no assigned DOI) -- not every paper has one."
          },
          "tldr": {
            "type": "string",
            "description": "A short, auto-generated one-sentence summary."
          },
          "type": {
            "type": "string",
            "description": "Observed as the literal string 'paper_details'."
          },
          "year": {
            "type": "number"
          },
          "title": {
            "type": "string"
          },
          "venue": {
            "type": "string"
          },
          "source": {
            "type": "string",
            "description": "Which citation-graph source resolved this record, e.g. 'arxiv'."
          },
          "authors": {
            "type": "array",
            "items": {
              "type": "string"
            },
            "description": "Author names as published on the paper."
          },
          "citedBy": {
            "type": "array",
            "items": {
              "type": "object",
              "properties": {
                "doi": {
                  "type": [
                    "string",
                    "null"
                  ],
                  "description": "Every real entry observed carries a DOI, but the field is declared nullable to match `references[].doi`'s confirmed behavior rather than assume this list is always fully populated."
                },
                "year": {
                  "type": "number"
                },
                "title": {
                  "type": "string"
                },
                "citedByCount": {
                  "type": "number"
                }
              },
              "additionalProperties": true
            },
            "description": "Recent works that cite this paper, capped by the `cite_limit` input."
          },
          "abstract": {
            "type": "string"
          },
          "published": {
            "type": "string",
            "description": "Publication date-time string, e.g. '2017-06-12T17:57:34Z'."
          },
          "openAlexId": {
            "type": [
              "string",
              "null"
            ],
            "description": "Observed null on the one real fixture captured."
          },
          "references": {
            "type": "array",
            "items": {
              "type": "object",
              "properties": {
                "doi": {
                  "type": [
                    "string",
                    "null"
                  ],
                  "description": "Null for several real entries observed -- not every cited work has a DOI on file."
                },
                "year": {
                  "type": "number"
                },
                "title": {
                  "type": "string"
                },
                "citedByCount": {
                  "type": "number"
                }
              },
              "additionalProperties": true
            },
            "description": "The works this paper cites, capped by the `ref_limit` input."
          },
          "citedByCount": {
            "type": [
              "number",
              "null"
            ],
            "description": "Observed null on the one real fixture captured."
          },
          "citationCount": {
            "type": [
              "number",
              "null"
            ],
            "description": "Observed null on the one real fixture captured; unconfirmed whether this ever differs from `citedByCount` when populated."
          },
          "fieldsOfStudy": {
            "type": "array",
            "items": {
              "type": "string"
            }
          },
          "referenceCount": {
            "type": "number"
          },
          "citationGraphSource": {
            "type": "string",
            "description": "Which upstream citation graph supplied citation counts, e.g. 'semanticscholar'."
          },
          "influentialCitationCount": {
            "type": "number"
          }
        },
        "additionalProperties": true
      }
    },
    "message": {
      "type": "string",
      "description": "Human-readable error text accompanying `code`."
    }
  },
  "description": "The paper lookup result, as returned at routing.responseResultPath ($.output). A successful lookup returns `count`/`items`; an id or DOI that does not resolve returns `code`/`message` instead (see examples/unknown-id-empty.json) -- no field below is guaranteed present on every call.",
  "additionalProperties": true
}