# LexRails U.S. Code Citation Validator

> LexRails U.S. Code Citation Validator is a paid API for AI agents from lex.chainverdict.xyz, paid per call via x402, $0.009/call, status unknown (last checked 2026-09-15).

Validates whether a given U.S. Code citation (title and optional section) is real and properly formed, returning a boolean result with an attestation object.

## Facts

- Endpoint: GET https://lex.chainverdict.xyz/v1/uscode/validate
- Price: $0.009/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/lexrails-u-s-code-citation-validator-99b57d7a
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_JDnYjFO-PepJd8DaHAQPT

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 lexrails-u-s-code-citation-validator-99b57d7a
```

Example prompt: Can you check whether U.S. Code Title 42, Section 1983 is a real, valid citation — I need to make sure it actually exists before I include it in this legal brief.

## When to prefer this

Choose this endpoint when you need a fast, deterministic, per-call check on whether a specific U.S. Code citation actually exists — especially in agentic legal workflows where LLM hallucination of statutory references is a risk. It is particularly valuable when you need an attestation object for audit trails. Prefer it over general-purpose LLM self-checks, which are probabilistic, or full legal database subscriptions when you only need existence validation rather than full text retrieval.

## Known failure modes

- Missing required 'title' parameter returns validation error
- Malformed title or section strings may return valid:false without further detail
- Payment failure via x402 (insufficient USDC balance) blocks the call entirely
- Network or upstream lookup failure may return a 5xx error
- Ambiguous or partial section strings may yield inconclusive results

## How this service works

Validate a U.S. Code citation structurally (title exists, not reserved, section well-formed).

## Output

Returns a JSON object with a 'valid' boolean indicating whether the cited U.S. Code title/section exists and is properly formed, plus an '_attestation' object providing a cryptographic or structured proof of the check result for auditability.

## 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"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "required": [
      "title"
     ],
     "properties": {
      "title": {
       "type": "string",
       "description": "U.S. Code title number (1-54)"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object",
     "additionalProperties": true
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/lexrails-u-s-code-citation-validator-99b57d7a/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from lex.chainverdict.xyz](https://www.zero.xyz/host/lex.chainverdict.xyz/llms.txt)