# Semantic Scholar Citation Graph Lookup

> Semantic Scholar Citation Graph Lookup is a paid API for AI agents from payai.agentstools.dev, paid per call via x402, $0.02/call, status unknown (last checked 2026-09-15).

Returns the full citation graph for a paper — both outgoing references and incoming citations — with normalized records and influential-citation counts, given any common paper identifier or title.

## Facts

- Endpoint: GET https://payai.agentstools.dev/scholar/citations
- Price: $0.02/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/semantic-scholar-citation-graph-lookup-f6e3a7b2
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_z4IfmNykzCgx2vInmwvk4

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability semantic-scholar-citation-graph-lookup-f6e3a7b2
```

Example prompt: Can you pull the full citation graph for the paper '2401.01234' on arXiv — I want to see both what it cites and what papers have cited it, plus the Semantic Scholar influential-citation count?

## When to prefer this

Use this endpoint when you need to explore the citation network around a specific known paper — either to find its sources (references) or downstream impact (who cited it). Prefer this over a general literature search when you already have an identifier (DOI, arXiv ID, PMID, etc.) or a precise title and need structured, bidirectional citation data including Semantic Scholar's influential-citation signal.

## Known failure modes

- Paper not found for the given identifier — returns empty results or a not-found error
- Ambiguous title match — may resolve to wrong paper if title is non-unique
- Rate limiting or payment failure — endpoint returns 402 if USDC payment not accepted
- arXiv/DOI format error — returns validation error if identifier is malformed
- Limit parameter out of range (must be 1–50) — returns schema validation error

## How this service works

Citation graph of a paper: the works it references (outgoing) and the works that cite it (incoming), each as normalized records, plus the Semantic Scholar influential-citation count. Give a doi, arxiv, pmid, openalex_id or title. Ideal for literature review and prior-art mapping.

## Output

Returns a citation graph object with two lists: outgoing references (works the paper cites) and incoming citations (works that cite the paper), each as normalized records with metadata such as title, authors, year, and identifiers, plus the Semantic Scholar influential-citation count for the paper.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET",
      "HEAD",
      "DELETE"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "required": [],
     "properties": {
      "id": {
       "type": "string",
       "description": "Any single identifier; its type is auto-detected"
      },
      "doi": {
       "type": "string",
       "description": "DOI, with or without a doi.org prefix"
      },
      "pmid": {
       "type": "string",
       "description": "PubMed id (digits)"
      },
      "arxiv": {
       "type": "string",
       "description": "arXiv id such as 2401.01234"
      },
      "limit": {
       "type": "integer",
       "maximum": 50,
       "minimum": 1,
       "description": "Max items to return, default 10"
      },
      "pmcid": {
       "type": "string",
       "description": "PubMed Central id such as PMC1234567"
      },
      "title": {
       "type": "string",
       "description": "Paper title to resolve by search"
      },
      "openalex_id": {
       "type": "string",
       "description": "OpenAlex work id such as W2741809807"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/semantic-scholar-citation-graph-lookup-f6e3a7b2/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from payai.agentstools.dev](https://www.zero.xyz/host/payai.agentstools.dev/llms.txt)