> For the complete documentation index, see [llms.txt](https://docs.layerlens.ai/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.layerlens.ai/4.2-industry-use-cases/pattern-2.md).

# Pattern: AI research citation verification

Legal — AI research citation verification pattern. Citation-existence scorer, holding-accuracy judge, per-session block on unverified output.

An AI legal research assistant answers case-law and statutory questions, drafts memo passages, and supports brief writing. The output cites cases, statutes, and regulations. A single fabricated citation in a filing is a sanctionable event — see *Mata v. Avianca, Inc.*, No. 22-cv-1461 (S.D.N.Y. June 22, 2023).

This pattern shows how to evaluate every research-tool output so a fabricated citation can never reach a court filing.

## What's at stake

| Risk dimension                                        | Magnitude                                    | Framework                               |
| ----------------------------------------------------- | -------------------------------------------- | --------------------------------------- |
| Court sanctions per *Mata*-style filing               | Cited sanctions $5K + reputational loss      | Public court orders                     |
| Bar discipline                                        | Public reprimand to suspension; case-by-case | State bar rules of professional conduct |
| Malpractice exposure for filed hallucinated citations | Multi-million-dollar settlements             | Public legal-malpractice filings        |
| Firm reputation in client and ABA Journal coverage    | Long-tail damage cycle                       | Industry trade press                    |

## The evaluation pattern

A two-stage evaluation runs on every research-tool output:

1. **Custom code grader (citation existence)** — every cited case, statute, or regulation is looked up against an authoritative legal database. Any citation that doesn't resolve = fabricated. Hallucination rate must be **0%** for the evaluation to pass.
2. **Holding-accuracy judge** (GEPA-tuned against ≥50 attorney-labeled examples — scored output) — for cases that exist, does the cited case actually stand for the proposition the AI claims? Does the quoted passage match the source verbatim?

> Don't have labels yet? See [Bootstrap a judge before GEPA](https://github.com/LayerLens/gitbook-full/blob/main/08-evaluate/guides/bootstrap-judges.md) for the week-1 setup.

3. **Continuous trace evaluation** — every production research session is scored. Sessions with any unverified citation are flagged in-app for attorney review **before any output can be acted on**. The flag is a hard gate; attorneys can override only after explicit acknowledgment.
4. **Compare-models** — when prompt or model changes are proposed, run the existing regression set across both; pick the variant with the lower hallucination rate at equal or better holding-accuracy.

The same pattern works for statutes, regulations, and internal precedent citations.

## Configuration in code

```python
# Python (SDK)
from layerlens import Stratix
client = Stratix()

citation_scorer = client.scorers.create_code(
 name="citation-existence",
 code="""
unresolved = [c for c in extract_citations(output) if not legal_db.lookup(c)]
result = {'passed': len(unresolved) == 0, 'fabricated': unresolved}
""",
)

holding_judge = client.judges.create(
 name="holding-accuracy",
 evaluation_goal="For each cited case, does the case actually stand for the proposition the OUTPUT claims? Quoted passages must match the source verbatim.",
)

trace_eval = client.trace_evaluations.create(
 trace_set={"tags": {"feature": "legal-research"}},
 scorers=[citation_scorer.id],
 judges=[holding_judge.id],
 schedule="per-session",
)
```

```typescript
// TypeScript (REST) — same trace eval from a Node service
const r = await fetch("https://stratix.layerlens.ai/api/v1/trace-evaluations", {
 method: "POST",
 headers: {
 "X-API-Key": process.env.LAYERLENS_STRATIX_API_KEY!,
 "Content-Type": "application/json",
 },
 body: JSON.stringify({
 trace_set: { tags: { feature: "legal-research" } },
 scorers: [citationScorerId],
 judges: [holdingJudgeId],
 schedule: "per-session",
 }),
});
```

## What you get

* Hallucination rate held at 0% on filed-output paths — the gate is a hard block, not a warning.
* Holding-accuracy judge agreement with senior associates above 90% after GEPA optimization.
* Documented evaluation evidence — the evaluation IDs and per-citation verification artifacts — to show partners, clients, and (if needed) the court that AI-assisted research operates under verification controls.
* Attorneys treat the AI as a research-acceleration tool, not a citation source. Which is what the AI should be.

## Stratix capabilities used

* [Custom code grader](https://github.com/LayerLens/gitbook-full/blob/main/08-evaluate/cookbook/custom-code-scorer.md) — citation-existence verification against legal databases
* [Judges with GEPA optimization](/8.-evaluate-score-the-outputs/judges-1.md) — holding accuracy and quote accuracy
* [Trace evaluations](/8.-evaluate-score-the-outputs/trace-evaluations.md) — every production session
* [Notifications](https://github.com/LayerLens/gitbook-full/blob/main/13-reference/sdk-python/notifications.md) — flag unverified citations for attorney review

## Replicate this

* [Industry → Legal](https://github.com/LayerLens/gitbook-full/blob/main/04-use-cases/industry/legal/README.md)
* [Cookbook: catch hallucinations](https://github.com/LayerLens/gitbook-full/blob/main/08-evaluate/cookbook/catch-hallucinations.md)
* [Cookbook: legal contract-review faithfulness](https://github.com/LayerLens/gitbook-full/blob/main/04-use-cases/industry/legal/cookbook/industry-legal-contract.md) (analogous pattern for transactional work)
* [Use case: RAG evaluation](/4.1-general-use-cases/rag-evaluation.md)