scp-light

name	scp-light
description	Lightweight single-command SCP flow to pay HTTP 402-protected URLs through hub routing. Handles offer discovery, smart offer selection, channel funding, and payment automatically. Use when user says "auto-pay", "pay URL", "quick pay", "scp light", or wants one-step 402 payment without manual channel management.
compatibility	Requires Node.js 18+, npm, EVM RPC access, and AGENT_PRIVATE_KEY.
metadata	{"author":"x402s","version":"2.0"}

SCP Light

Overview

Automate 402 URL payment using a single script that handles offer discovery, AI-aware offer selection, channel checks, funding, and payment submission.

Runbook

Run from the x402s/ project root:

node skill/scp-light/scripts/auto_402_hub_pay.js <url>

Common options:

node skill/scp-light/scripts/auto_402_hub_pay.js <url> \
  --topup-payments 100 \
  --method GET \
  --route hub \
  --network base \
  --rpc-urls https://mainnet.base.org,https://base-rpc.publicnode.com

POST with JSON body:

node skill/scp-light/scripts/auto_402_hub_pay.js https://pogchamp.tv/chat/chat \
  --method POST \
  --json '{"message":"hello"}' \
  --network base

Dry-run:

node skill/scp-light/scripts/auto_402_hub_pay.js <url> --network base --dry-run

What The Script Does

1. Load .env from x402s/ if present.
2. Discover offers from the target URL and choose the best route (hub by default).
   • If multiple hub offers and no channel: checks wallet balance viability per offer.
3. For hub offers, check whether a hub:<endpoint> channel exists in agent state.
4. If missing or underfunded, calculate target funding, check wallet balance, open/fund channel.
5. If ERC-20 and allowance low, submit approve(MaxUint256).
6. Submit paid request using SCP signing flow.
7. Print summary: route, amount, ticket id, receipt/payment ids.

AI-Aware Offer Selection

The script scores offers by channel readiness (2=funded, 1=underfunded, 0=none), then by cost. When AI is selecting on behalf of the user:

• Funded channel always wins — don't open a new channel when one exists
• Cross-asset comparison — 0.01 USDC ≈ $0.01; 0.00001 ETH ≈ $0.025 at $2500/ETH
• Network gas matters for new channels — Base gas ~$0.001, mainnet ~$1-5
• Zero-fee hubs preferred — pay.eth charges 0 base + 0 bps

Inputs

Required:

• AGENT_PRIVATE_KEY (or enter interactively in TTY)

Optional:

• NETWORK or NETWORKS
• RPC_URL, CONTRACT_ADDRESS
• MAX_AMOUNT, MAX_FEE
• AGENT_STATE_DIR
• X402S_ROOT (defaults to workspace x402s)

Notes

• Alias networks (base, sepolia) or CAIP (eip155:*); script normalizes internally.
• --topup-payments controls channel buffer size (default: 100).
• In interactive TTY, the script asks how many payments top-up should cover (unless --topup-payments is set).
• If payee uses PAYMENT_MODE=pay_once, this script performs the first paid call; follow-up calls reuse the access grant.
• Read references/env-and-flags.md for full flag/env details and troubleshooting.