# ethskills-x402

Current Ethereum knowledge for AI agents — 23 researched topics + live on-chain state at $0.02, 5 merged deployment briefings at $0.10, 18 live data endpoints from $0.002. x402 pay-per-call, USDC on Base.

Base URL: https://x402centre.roverbot.workers.dev

Paid (x402, USDC on Base; unpaid GET -> 402 challenge):
/live/state — $0.020000 — Live on-chain state: gas + transfer cost + ETH/USD + head block across L1/Base/Arbitrum/Optimism, sampled fresh per call and block-anchored.
/research/why-ethereum — $0.020000 — Research topic brief for agents: Why Ethereum — upgrades, honest tradeoffs, the AI agent angle.
/research/ship — $0.020000 — Research topic brief for agents: End-to-end: dApp idea to production (routes through all skills).
/research/crops — $0.020000 — Research topic brief for agents: CROPS architecture review: censorship, openness, privacy, security.
/research/protocol — $0.020000 — Research topic brief for agents: EIP lifecycle, fork process, what's actually planned.
/research/gas — $0.020000 — Research topic brief for agents: Real gas prices (<1 gwei) and what actions actually cost.
/research/wallets — $0.020000 — Research topic brief for agents: Creating wallets, safe signing, multisig, account abstraction.
/research/l2s — $0.020000 — Research topic brief for agents: Current L2 landscape, selection guide, bridging, deployment gotchas.
/research/standards — $0.020000 — Research topic brief for agents: ERC-20/721/1155, ERC-8004 agent identity, EIP-7702, EIP-3009, x402.
/research/tools — $0.020000 — Research topic brief for agents: Frameworks, RPCs, MCPs, Foundry — what actually works today.
/research/building-blocks — $0.020000 — Research topic brief for agents: DeFi legos: Uniswap, Aave, Curve — and how to compose them.
/research/orchestration — $0.020000 — Research topic brief for agents: Three-phase build system for complete Ethereum applications.
/research/addresses — $0.020000 — Research topic brief for agents: Verified contract addresses — stop hallucinating addresses.
/research/concepts — $0.020000 — Research topic brief for agents: Mental models: nothing is automatic, randomness, incentives.
/research/security — $0.020000 — Research topic brief for agents: Solidity vulnerabilities with defensive code, pre-deploy checklist.
/research/noir — $0.020000 — Research topic brief for agents: Noir ZK circuits: commitment-nullifier pattern, Solidity verifiers.
/research/testing — $0.020000 — Research topic brief for agents: Foundry unit/fuzz/fork/invariant testing — what to test, what not to.
/research/indexing — $0.020000 — Research topic brief for agents: Events as API, The Graph, Dune, reading current vs historical state.
/research/frontend-ux — $0.020000 — Research topic brief for agents: Onchain button loaders, four-state flow, USD values, error UX.
/research/frontend-playbook — $0.020000 — Research topic brief for agents: IPFS/Vercel/ENS deploy pipeline and pre-publish checklist.
/research/qa — $0.020000 — Research topic brief for agents: Pre-ship QA audit: wallet flows, branding, RPC config, deep linking.
/research/audit — $0.020000 — Research topic brief for agents: Smart contract security audit checklist, 19 domains.
/research/where-agents-earn-work — $0.020000 — Research topic brief for agents: Where AI agents get paid work on Base: bounty venues, per-call x402, and on-chain payment evidence.
/research/verify-an-x402-settlement — $0.020000 — Research topic brief for agents: I paid with x402: how a buyer verifies the settlement landed — 402 → EIP-3009 → PAYMENT-RESPONSE, what settled means on Base, and a hand-checkable worked example.
/briefs/ship-a-dapp — $0.100000 — Merged deployment briefing: Merged: plan -> architecture -> CROPS -> contracts -> test -> ship.
/briefs/pre-deploy — $0.100000 — Merged deployment briefing: Merged: security + testing + QA into one pre-flight package.
/briefs/l2-selection — $0.100000 — Merged deployment briefing: Merged: L2 comparison + real costs + when mainnet actually wins.
/briefs/agent-onchain — $0.100000 — Merged deployment briefing: Merged: agent wallet guardrails + ERC-8004 identity + x402 payments.
/briefs/defi-composable — $0.100000 — Merged deployment briefing: Merged: DeFi legos + verified addresses + build system + safety.
/data/pm/markets — $0.005000 — Polymarket public markets (?q=, ?active=true, ?closed=, ?order=volume24hr|liquidity|endDate, ?limit=1..50 default 20): rows with question, slug, event URL, per-outcome numeric prices, 24h volume, liquidity, endDate; sorted server-side. Market data only, not investment advice.
/data/hl/carry — $0.002000 — Hyperliquid carry per perp (?coin=HYPE): funding APR now/1d/7d/30d, positive-hour share, perp depth at 10/25/50 bps each side, USDC spot hedge and its depth, taker round-trip cost, breakeven days, thin-book flags.
/data/x402/preflight — $0.005000 — Is this x402 offer safe to sign? Pass ?url= the paid resource. Checks payTo, canonical USDC, EIP-712 domain vs chain, resource host, amount, window and /.well-known/x402 on 7 EVM chains, v1 and v2. SAFE / WARN / UNSAFE.
/data/x402/audit — $0.010000 — Passive seller audit of an x402 origin (?origin=): 402 + decodable PAYMENT-REQUIRED shape, payTo sanity, network and USDC canonicality, resource.url host match, well-known payTo cross-check, amount and window flags. SAFE / WARN / UNSAFE or not_an_x402_origin. Data only - never a trade instruction.
/data/sec/filing — $0.005000 — SEC filing triggers for a ticker or CIK (?ticker=COIN or ?cik=; ?windowDays=45): latest 10-Q plus recent 8-Ks with the EDGAR item codes (1.01-9.01) found per document, filing/report dates, accessions and per-document EDGAR URLs. Data only - never a trade instruction.
/data/base/usdc — $0.004000 — Base USDC transfer facts (?tx=0x.. or ?address=0x..&n=1..50): amount, from, to, block, gasUsed, status, the canonical-USDC Transfer rows, and whether an EIP-3009 transferWithAuthorization leg is present. Last-n USDC transfers for an address, newest-first. On-chain facts - not investment advice.
/data/xv/funding — $0.002000 — Cross-venue funding spread per coin (?coin=ETH): Hyperliquid's own funding vs Lighter's own (dark-venue) funding, APR at each hourly cadence, the spread in bps/yr with direction, the CEX basis mirrors, and book depth (USD within 25 bps, thin flags) on both books. Data, not a trade instruction.
/data/hl/carry-screen — $0.004000 — Hyperliquid carry screener (?n=1..25, default 10): spot-hedgeable perps capped at 50 by OI, ranked by 7d realized funding APR; per row: hedge pair, OI USD, current rate + direction, perp and hedge depth within 25 bps, thin-book gate verdict. Data, not a trade instruction.
/data/hl/basis — $0.002000 — Perp-vs-spot basis on one Hyperliquid perp (?coin=ETH): signed basis bps (premium/discount), taker round-trip cost and cover flag, OI USD, USDC spot hedge, depth within 25 bps per book, thin-book verdict, and a divergence flag. Per-coin twin of /data/hl/basis-screen. Data, not a trade instruction.
/data/hl/basis-screen — $0.004000 — Hyperliquid perp basis screener (?n=1..25, default 10): spot-mapped perps ranked by live perp-vs-spot basis in bps; divergence gate (legs at the same price level), OI USD, taker round-trip cost and cover flag, perp and hedge depth within 25 bps, thin-book verdict. Data, not a trade instruction.
/data/xv/funding-screen — $0.004000 — Cross-venue funding screener: perps on both Hyperliquid and Lighter ranked by the spread of the venues' own funding (APR + bps/yr, delta-neutral direction), top n (default 10) with both books' depth within 25 bps, thin-book flags, open interest in USD. Native rates, never CEX mirrors. Data only.
/data/hl/funding-pair — $0.002000 — Cross-coin Hyperliquid funding spread (?coinA=X&coinB=Y): 1d/7d/30d windows of both legs' hourly funding (mean/APR/cv/flips) and the GROSS spread A-B on jointly-printed hours; spreadSide, 4 flags, OI context, applied policy. Gross, no execution cost; data only, never a trade instruction.
/data/sec/changes — $0.005000 — SEC 8-K item watch (?ticker= or ?cik=, ?since= (default 30d)): every 8-K filed since the date with the EDGAR item codes found per document, filing and report dates, accessions, per-document EDGAR addresses, and a changes summary of which items on which dates. Data only - never a trade instruction.
/data/base/token-check — $0.010000 — Base ERC-20 safety facts (?address=0x..): name, symbol, decimals, totalSupply, bytecode size, owner/renounce state, EIP-1967 upgradeability, plus DexScreener price, deepest-pair liquidity, pair age, 24h volume. Rules-based LOW/MEDIUM/HIGH verdict, one reason per fired rule. Facts, not advice.
/data/px/fear-greed — $0.005000 — Crypto Fear and Greed index (alternative.me, keyless): current value 0..100 with its sentiment label, ?days=1..30 default 7 of daily history, avg, low, high and trend (rising|falling|flat). Sentiment data, not investment advice.
/data/x402/receipt — $0.005000 — Verify an x402 settlement on Base (?tx=0x..&payTo=0x.., ?amountUsd= optional): receipt status, block, from, plus whether a canonical-USDC Transfer to the expected payTo is in the receipt - settled, matchedLog {to, amountUsd}, payToMatch, amountMatch. Facts only.
/data/px/trending — $0.005000 — Coins agents are searching right now: CoinGecko trending (?n=1..25 default 10) with rank (current list position), USD price and 24h change, keyless. Market data only, not investment advice.
/data/px/rank — $0.005000 — A coin's market profile in one call: ?symbol=BTC|ETH|SOL (default BTC) -> rank, market cap, USD price, 24h/7d change, ATH and distance from ATH (fromAthPct), keyless CoinGecko. Market data only, not investment advice.

Free:
/catalog — Machine menu: every paid path with price and x402 terms, plus the free paths.
/receipts — Public settlement ledger: settled payments, gross USD, last settlement.
/stats — Free demand telemetry: aggregate call counts by path (no per-wallet data).
/healthz — Liveness probe: ok flag, network, payTo configured.
/.well-known/x402 — x402 discovery document: payment terms and all paid resources.
/ — Human landing page (HTML).