# RealCite Case Citation Verifier

> RealCite Case Citation Verifier is a paid API for AI agents from goodsong.dev, paid per call via x402, $0.01/call, status unknown (last checked 2026-09-15).

Verifies whether a legal case citation exists in CourtListener and whether the provided case name matches the canonical record, catching fabricated citations.

## Facts

- Endpoint: POST https://goodsong.dev/verify/case
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/realcite-case-citation-verifier-70e3d981
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_aWWIopNA97V_kHY3Clw8k

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 realcite-case-citation-verifier-70e3d981 -d '<json body>'
```

Example prompt: Can you check whether the case citation '576 U.S. 644' actually exists and whether it matches the case name 'Obergefell v. Hodges'? I want to make sure this isn't a hallucinated citation before I use it.

## When to prefer this

Use this endpoint when an AI agent or human has produced a legal case citation and you need to verify it isn't fabricated — especially when the citation number looks plausible but the case name may be invented. Best for checking U.S. court cases indexed by CourtListener. Not suitable for checking whether a case is still valid precedent (Shepardizing).

## Known failure modes

- Citation not found in CourtListener (case may be real but not indexed)
- Case name provided does not match canonical record for an existing citation
- Citation format is malformed or unparseable
- CourtListener API unavailable or rate-limited
- Does not indicate whether a case has been overruled or is still good law

## How this service works

Verify a legal case citation: does it exist, and does the given case name match the canonical record? Catches a fabricated case citation, including a real-looking citation number paired with an invented case name. Checked against CourtListener. Does not check whether a case is still good law -- no free authoritative source publishes that.

## Output

Returns whether the given case citation exists in CourtListener's database, and if a case name was provided, whether it matches the canonical record for that citation. Flags fabricated or mismatched citations but does not assess whether the case is still good law.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "citation": {
   "type": "string",
   "description": "The case citation, e.g. '576 U.S. 644'."
  },
  "case_name": {
   "type": "string",
   "description": "Optional case name to cross-check against the citation."
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/realcite-case-citation-verifier-70e3d981/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from goodsong.dev](https://www.zero.xyz/host/goodsong.dev/llms.txt)