OpenCitations Index SPARQL Query

opencitationsindexsparql/sparql-query

Runs a read-only SPARQL SELECT against the OpenCitations Index, the open graph of citation links between scholarly works (cito:Citation entities with cito:hasCitingEntity and cito:hasCitedEntity pointing at OpenCitations Meta work identifiers). The query must end in a LIMIT of at most three digits; an unbounded scan of the whole index times out. Returns one flat object per row. Open citation data published by OpenCitations under CC0; served by Eden Engine and not an official OpenCitations product.

activeper callv1

Price

$0.0026 per call

You pay the price shown. If a call turns out to cost more than its quote, you pay the actual price, capped at twice the quote. No monthly minimum. Top-ups start at $0.50.

Data source

OpenCitations (opencitations.net)

Data from the OpenCitations Index (opencitations.net), published as CC0 open data. No credit is required; credit offered as a courtesy: OpenCitations. Provided as published, with no warranty of accuracy. Served by Eden Engine; not an official OpenCitations product.

Use it

Five steps: search, inspect, learn, run, settle. No per-tool setup; your agent reaches this tool through the meta-tools it already has.

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agent

// 1. search: find the tool
omnial_search({ query: "what you need" })

// 2. inspect: price and input schema
omnial_inspect({ tool: "opencitationsindexsparql/sparql-query" })

// 3. learn: read the usage guide at runtime
omnial_learn({ tool: "opencitationsindexsparql/sparql-query" })

// 4. run: price the exact call first, then run it
omnial_execute({ tool: "opencitationsindexsparql/sparql-query", input: { /* see input_schema */ }, dry_run: true })
omnial_execute({ tool: "opencitationsindexsparql/sparql-query", input: { /* ... */ } })

// 5. settle: the call is charged when it finishes, nothing to do

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Pricing

Every charge this tool can incur.

Charge	Price
Per call	$0.0026

Updated: Oct 21, 2026

Input and output schemas

Input schema

input_schema.json

{
  "type": "object",
  "required": [
    "query"
  ],
  "properties": {
    "query": {
      "type": "string",
      "pattern": "^(?=[\\s\\S]*\\b[Ss][Ee][Ll][Ee][Cc][Tt]\\b)(?:[^#<]|<(?![^<>\"{}|^\\x60\\\\\\s]*>)|<[^<>\"{}|^\\x60\\\\\\s]*>)*\\b[Ll][Ii][Mm][Ii][Tt]\\s+[1-9][0-9]{0,2}\\s*$",
      "maxLength": 2000,
      "minLength": 20,
      "description": "A SPARQL SELECT ending in LIMIT n (1 to 999) with no # comment outside a <...> IRI, for example PREFIX cito: <http://purl.org/spar/cito/> SELECT ?ci WHERE { ?ci cito:hasCitedEntity <https://w3id.org/oc/meta/br/061203747253> } LIMIT 10. Prefer a bound subject or object: a pattern with no constant scans the whole index."
    }
  },
  "additionalProperties": false
}

Output schema

output_schema.json

{
  "type": "object",
  "required": [
    "results"
  ],
  "properties": {
    "results": {
      "type": "array",
      "items": {
        "type": "object",
        "description": "One result row: each selected variable as a string. A variable the query left unbound is absent.",
        "additionalProperties": true
      },
      "description": "One entry per row; empty when nothing matches."
    }
  },
  "description": "The rows of the result set, in the endpoint's order.",
  "additionalProperties": false
}