# US Federal Register Search

> US Federal Register Search is a paid API for AI agents from twin.unykorn.org, paid per call via x402, $0.003/call, status unknown (last checked 2026-10-03).

Search the US Federal Register for rules, proposed rules, notices, and presidential documents (executive orders) by keyword, agency, and document type

## Facts

- Endpoint: POST https://twin.unykorn.org/records/federal-register?utm_source=zero.xyz
- Price: $0.003/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-03
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/us-federal-register-search-61e94976
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_5JzVo2DdhGkxH3WJ51_Hm

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 us-federal-register-search-61e94976 -d '<json body>'
```

Example prompt: Search the Federal Register for any recent proposed rules or notices from the EPA about clean water standards — give me up to 20 results.

## When to prefer this

Choose this endpoint when you need to search official US government regulatory documents — rules, proposed rules, notices, or executive orders — by keyword and optionally by agency or document type. Prefer this over general web search when you need structured, authoritative regulatory data directly from the Federal Register, especially for compliance research, regulatory monitoring, or legal research tasks.

## Known failure modes

- No results found for obscure or misspelled query terms
- Invalid agency slug returns an error or empty results
- doc_type enum value mismatch causes rejection
- Limit exceeding maximum of 50 is rejected
- Federal Register API upstream downtime causes service unavailability
- Overly broad queries may return irrelevant documents

## How this service works

US Federal Register search: rules, proposed rules, notices, executive orders — Genesis402 / UnyKorn Operator Network

## Output

Returns a list of Federal Register documents matching the query, including document titles, document types (RULE, PRORULE, NOTICE, PRESDOCU), issuing agency, publication dates, and relevant metadata such as document numbers and abstracts, up to the specified limit.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "params": {
   "type": "object",
   "properties": {
    "q": {
     "type": "string",
     "description": "required"
    },
    "limit": {
     "type": "integer",
     "maximum": 50,
     "minimum": 1,
     "description": "optional: max rows (default 10, max 50)"
    },
    "agency": {
     "type": "string",
     "description": "optional agency slug, e.g. securities-and-exchange-commission"
    },
    "doc_type": {
     "enum": [
      "RULE",
      "PRORULE",
      "NOTICE",
      "PRESDOCU"
     ],
     "type": "string",
     "description": "optional: RULE | PRORULE | NOTICE | PRESDOCU"
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "ok": true,
  "type": "federal-register-search",
  "receipt": {
   "tx_hash": "0x<64hex>",
   "amount_usd": 0.003,
   "receipt_id": "g402-<16hex>"
  },
  "sources": [
   {
    "ok": true,
    "name": "<source>"
   }
  ],
  "limitations": "<text>",
  "generated_at": "<iso time>",
  "evidence_hash": "sha256:<64hex>"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/us-federal-register-search-61e94976/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from twin.unykorn.org](https://www.zero.xyz/host/twin.unykorn.org/llms.txt)