law.usc-section

Fetch the authoritative current text of any United States Code section by title and section number — for example title 17, section 107 returns the fair-use statute. Returns the canonical citation, heading, hierarchy context (title/chapter), full statutory plain text, the Statutes-at-Large source credit, and a link to the official OLRC page; set includeNotes=true to also get editorial notes (amendment history, effective dates). Hyphenated and lettered sections like 1395w-4 or 78j work. Data from the Office of the Law Revision Counsel current ("prelim") edition, public domain — verify statutory citations against the authoritative source instead of relying on model memory. For federal regulations see /api/law/cfr-section; for case law see /api/law/case-verify.

price

$0.0018 USDC per call

method

GET/api/law/usc-section

payment

x402 v2 · USDC on Base (EIP-3009) or Solana (SPL transfer)

auth

None. Sign the payment, retry with PAYMENT-SIGNATURE.

tier

Tier 0 — no paid upstream

Parameters

Name	Type	Description
`title`required	integer	USC title number, 1-54 (e.g. 17 for Copyrights, 26 for Internal Revenue Code, 42 for Public Health and Welfare). min 1 · max 54
`section`required	string	Section number, e.g. "107", "78j", or "1395w-4". match ^[0-9]{1,5}[a-zA-Z]{0,3}(-[0-9a-zA-Z]{1,8})?$
`includeNotes`		Include editorial notes (amendment history, effective dates, cross-references). Default false — notes can be long.

Code samples

cURLbash

# 1. Probe with no auth → 402 envelope with PaymentRequirements
curl -sS 'https://2s.io/api/law/usc-section?title=1&section=12345678&includeNotes=false'

# 2. Sign + retry with PAYMENT-SIGNATURE:
curl -sS 'https://2s.io/api/law/usc-section?title=1&section=12345678&includeNotes=false' \
  -H 'PAYMENT-SIGNATURE: <base64-json-payload>'

# Or use the canonical runner (handles probe → sign → retry):
#   EVM_PRIVATE_KEY=0x... node --env-file=.env.local \
#     --experimental-strip-types scripts/x402-pay.ts \
#     'https://2s.io/api/law/usc-section?title=1&section=12345678&includeNotes=false'

TypeScript / Node — @2sio/sdktypescript

import { TwoS } from '@2sio/sdk'

const client = new TwoS({
  privateKey: process.env.EVM_PRIVATE_KEY as `0x${string}`,
})

const result = await client.law.uscSection({
  "title": 1,
  "section": "12345678",
  "includeNotes": false
})

console.log('endpoint:', result.endpoint)
console.log('cost:', result.costUsd, 'USDC')
console.log('tx:', result.settlement?.txHash)
console.log('data:', result.data)

Python — 2siopython

import os
from twosio import TwoS

client = TwoS(private_key=os.environ["EVM_PRIVATE_KEY"])

result = client.law.usc_section(title=1, section="12345678", includeNotes=False)

print("endpoint:", result.endpoint)
print("cost:", result.cost_usd, "USDC")
print("tx:", (result.settlement or {}).get("tx_hash"))
print("data:", result.data)

MCP — Claude Desktop / AgentKit / any MCP hostjson

// 1. Add @2sio/mcp to your MCP host config (Claude Desktop example below).
//    EVM_PRIVATE_KEY funds x402 payments per call.

// claude_desktop_config.json
{
  "mcpServers": {
    "2sio": {
      "command": "npx",
      "args": ["-y", "@2sio/mcp"],
      "env": { "EVM_PRIVATE_KEY": "0x..." }
    }
  }
}

// 2. Once the server is running, agents call this tool via standard MCP:

{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "tools/call",
  "params": {
    "name": "law.usc-section",
    "arguments": {
      "title": 1,
      "section": "12345678",
      "includeNotes": false
    }
  }
}

Response

Field	Type	Description
`citation`	string	Canonical citation, e.g. "17 U.S.C. § 107".
`title`	integer	USC title number.
`section`	string	Section number as requested.
`heading`	string	Official section heading.
`context`	string	Hierarchy breadcrumb (title › chapter › …).
`text`	string	Plain-text statutory body (no editorial notes).
`sourceCredit`	string	Statutes-at-Large credit (enactment + amendment cites).
`notes`	string	Editorial notes, only when includeNotes=true.
`truncated`	boolean	True if a block was cut at the response cap (rare).
`edition`	string	USC edition served ("prelim" = current law).
`url`	string	Official uscode.house.gov page for the section.
`source`	object

Example response datajson

{
  "citation": "example",
  "title": 1,
  "section": "example",
  "heading": "example",
  "context": "example",
  "text": "example",
  "sourceCredit": "example",
  "notes": "example",
  "truncated": false,
  "edition": "example",
  "url": "example",
  "source": {
    "provider": "example",
    "url": "example",
    "license": "example"
  }
}

Discovery

/api/directory — full catalog of every endpoint
/openapi.json — OpenAPI 3.1 spec (per-op x-payment-info, x402Payment security)
/.well-known/x402 — machine-readable service descriptor for x402-aware crawlers
/.well-known/mcp/server-card.json — MCP SEP-1649 server card
/llms.txt — plain-text manifest for LLM ingestion

2s.io is x402-native. Every call is paid per-request from a USDC-funded EVM wallet on Base — no signup, no API keys, no monthly fees. Source code: github.com/2s-io/sdk.