Sluice: Instructions file for Claude Code

SLUICE — Project Rules & Constants (read this fully every session)

First action of every session: read this entire file. Everything you build obeys it. Working tree is /root/Sluice (this is NOT Tessera/Xyndicate/Agora/Apogee/Archon/Auralis — never touch those projects). Repo: Franlinozz/Sluice. Vercel project: sluice (prj_P12m6QjGi3gFtPSCfXbDTiGJRbi9, team franlinozzs-projects).

What we're building

Sluice is a settlement layer for the agent-paid web. Any unit of value — a read, a second, a citation, a listen, an API call — is metered and settled on Arc in USDC. Creators get paid per use; agents pay per use and DECIDE for themselves. Hero use case: AI research agents pay creators PER CITATION (the open, creator-owned alternative to Cloudflare Pay-Per-Crawl / RSL, which declare terms but don't settle).

Non-negotiable rules

1. NEVER fake data, balances, figures, transactions, or "working" integrations. A clearly labeled "beta"/"coming soon"/"roadmap" state ALWAYS beats a fake. Every number shown to a user must trace to a real on-chain (Arc testnet) event or a real DB record.
2. NO DEAD CONTROLS. Every button/link/toggle either works or is visibly disabled with a stated reason (tooltip/label). The product owner is not a deep dev and cannot spot a silent no-op — so there must be none.
3. Network-agnostic settlement. All chain/settlement access goes through ONE interface (packages/chain). Arc Testnet is primary; swapping the RPC provider (or, last resort, another network) must be a config change, never a code rewrite. Do NOT scatter RPC URLs/chain IDs.
4. Meter decoupled from settlement backend. The accrual engine must not care whether the final settle is Gateway-batched or a direct x402 call. If Gateway-on-Arc misbehaves, we can fall back to direct x402 settlement without touching accrual logic.
5. USDC DECIMALS DISCIPLINE (critical):
   • ERC-20 USDC used for PAYMENTS = 6 decimals. All payment amounts, EIP-3009 values, and ledger math use 6-decimal integer base units. Use viem parseUnits(amount, 6).
   • Arc's NATIVE GAS token is USDC displayed with 18 decimals. Never mix gas display with payment amounts. Keep a single money helper (packages/money) and route all amounts through it.
6. EIP-3009 is signed against the GATEWAY WALLET CONTRACT, not the USDC token contract. The x402 scheme field is "exact"; the string "GatewayWalletBatched" is the EIP-712 DOMAIN NAME placed in extra.name, with extra.verifyingContract = the Gateway Wallet. (This is the #1 thing teams get wrong — see "x402 payment requirements shape" below.)
7. One-time deposit required: a wallet must deposit USDC into the Gateway Wallet contract BEFORE it can make nanopayments. Build and surface this step explicitly.
8. Settlement LAG is real: seller earnings appear only AFTER Circle Gateway settles the batch on-chain (can take minutes). UI must show honest states: authorized → batching → settled. Never show settled balance the instant a payment is authorized.
9. Money in code is always integer base units (bigint). Format for display only at the edge. JSON cannot carry bigint — serialize bigints as strings, parse back at boundaries.
10. Verify before assuming. When unsure of an API shape, address, or version, READ the canonical source (links below) or the arc-nanopayments repo — do not invent signatures.
11. Commit after every green Definition of Done, with a clear message. Keep PR-sized diffs.
12. Secrets: server-only keys live in env, never in client bundles. In Next.js, only NEXT_PUBLIC_* is exposed to the browser. Private keys/API keys must NEVER be NEXT_PUBLIC_.