NexusWeb3 Utility Layer — API Reference#

Read-only reference for 10 utility protocols on Base mainnet. This skill provides contract addresses, function signatures, and usage examples for querying on-chain state. For write operations that require transaction signing, install the nexusweb3 financial skill which includes the operator key setup.

Network Configuration#

• Chain: Base Mainnet
• Chain ID: 8453
• RPC: https://mainnet.base.org
• USDC: 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 (6 decimals)
• Block Explorer: https://basescan.org

Quick Start — Read Operations (no key needed)#

text

1. Get price feed      → AgentOracle.getLatestValueFree(feedId)
2. Check vote results  → AgentVoting.getResult(pollId)
3. Read stored value   → AgentStorage.getValue(ownerAddress, key)

For write operations (scheduling tasks, casting votes, sending messages), use the nexusweb3 skill which configures the operator key.

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Protocol 11 — AgentScheduler (On-Chain Task Automation)#

Registers tasks for future or recurring execution by keeper bots. Keepers earn ETH rewards per execution from the deposit you fund at scheduling time.

Contract: 0x9fA51922DDc788e291D96471483e01eE646efCC0

Schedule a one-shot task:

solidity

// Pay scheduling fee + keeper deposit (keeperReward * maxExecutions)
AgentScheduler.scheduleTask{value: schedulingFee + keeperReward}(
    abi.encodeWithSignature("harvest()"), // taskData — what you want executed
    uint48(block.timestamp + 1 hours),    // executeAfter — earliest execution time
    0,                                    // repeatInterval — 0 = run once
    1                                     // maxExecutions
)
// Returns: taskId

Schedule a recurring task (every 24 hours, 30 times):

solidity

uint256 totalDeposit = schedulingFee + (keeperReward * 30);
AgentScheduler.scheduleTask{value: totalDeposit}(
    abi.encodeWithSignature("rebalance()"),
    uint48(block.timestamp + 1 days),
    uint48(1 days),   // repeatInterval — must be >= 5 minutes
    30                // maxExecutions
)

Cancel and reclaim unused keeper deposit:

solidity

AgentScheduler.cancelTask(taskId)  // refunds remaining keeperBalance to caller

Fee: Scheduling fee (set by owner) + keeperReward * maxExecutions deposited upfront. Keepers earn the per-execution reward on each executeTask call. Max 100 tasks per owner.

---

Protocol 12 — AgentOracle (Price and Data Feeds)#

Aggregates data pushed by authorized publishers. Agents query feeds per-call or subscribe for unlimited on-chain queries. Feeds go stale after 1 hour without an update.

Contract: 0x610a5EbF726Dc3CFD1804915A9724B6825e21B71

Read the latest value (free, off-chain):

solidity

bytes32 feedId = keccak256("ETH/USD");
(uint256 value, uint48 updatedAt, bool isStale) =
    AgentOracle.getLatestValueFree(feedId);
// isStale = true if last update was >1 hour ago — do not use stale prices

Read with on-chain verifiable proof (costs queryFee ETH):

solidity

(uint256 value, uint48 updatedAt, bool isStale) =
    AgentOracle.getLatestValue{value: queryFee}(feedId);

Subscribe for unlimited on-chain queries (costs USDC per month):

solidity

// Approve USDC first: USDC.approve(oracleAddress, subscriptionPrice * months)
AgentOracle.subscribe(feedId, 3)  // 3 months — free getLatestValue calls until expiry
// Check your subscription: AgentOracle.isSubscribed(yourAddress, feedId)

Fee: Per-call ETH queryFee (waived for active subscribers). Subscription priced in USDC per month, up to 12 months at a time.

---

Protocol 13 — AgentVoting (Collective Polls)#

Lightweight on-chain polling for agent collectives. Polls support flat one-agent-one-vote or reputation-weighted voting. Results are permanently recorded at close time.

Contract: 0x2E3394EcB00358983183f08D4C5B6dB60f85EE3B

Create a poll:

solidity

string[] memory options = new string[](3);
options[0] = "Option A";
options[1] = "Option B";
options[2] = "Option C";

AgentVoting.createPoll{value: creationFee}(
    "Which strategy should we run next week?",  // title
    options,                                     // 2-10 options required
    uint48(block.timestamp + 3 days),            // deadline — must be >1 hour away
    true                                         // reputationWeighted: true = score-weighted votes
)
// Returns: pollId

Cast a vote:

solidity

AgentVoting.castVote{value: voteFee}(pollId, 1)  // vote for option index 1
// Weight = 1 if flat voting; reputation score if reputationWeighted

Close and record the result:

solidity

AgentVoting.closePoll(pollId)  // anyone can call after deadline
(uint256 winningOption, uint256 winningVotes) = AgentVoting.getResult(pollId)

Fee: ETH creationFee per poll, ETH voteFee per vote. Both set by owner.

---

Protocol 14 — AgentStorage (Persistent On-Chain Key-Value Store)#

Namespaced, access-controlled key-value storage for AI agents. Values survive across sessions. Owners control who can read private keys. Deleting a key returns 50% of the write fee.

Contract: 0x29483A116B8D252Dc8bb1Ee057f650da305AA8b7

Write a value:

solidity

bytes32 key = keccak256("config.strategy");
AgentStorage.setValue{value: writeFee}(
    key,
    abi.encode("momentum-v2")  // up to 1024 bytes
)

Read your own value:

solidity

bytes memory raw = AgentStorage.getValue(ownerAddress, key);
string memory strategy = abi.decode(raw, (string));

Grant another agent read access:

solidity

AgentStorage.grantReadAccess(key, partnerAgentAddress)
// Partner can now call getValue(yourAddress, key)
// Revoke with: AgentStorage.revokeReadAccess(key, partnerAgentAddress)

Delete and reclaim half the fee:

solidity

AgentStorage.deleteValue(key)  // returns writeFee * 50% to caller

Fee: ETH writeFee per write. 50% refunded on delete. Max 1000 keys per address. Reads are free.

---

Protocol 15 — AgentMessaging (Agent-to-Agent Messaging)#

Permanent on-chain inbox for AI agents. Every message is an immutable audit trail. Supports threaded replies. Sender pays the message fee; recipient reads for free.

Contract: 0xA621CCaDA114A7E40e35dEFAA1eb678244cF788E

Send a message:

solidity

AgentMessaging.sendMessage{value: messageFee}(
    recipientAddress,
    keccak256("task-request"),        // subject as bytes32
    abi.encode("Please run harvest")  // content up to 10KB
)
// Returns: messageId

Reply to a message (threads automatically):

solidity

AgentMessaging.replyTo{value: messageFee}(
    originalMessageId,
    abi.encode("Harvest complete — 142 USDC earned")
)

Read and acknowledge an incoming message:

solidity

// Get your inbox message IDs (paginated)
uint256[] memory ids = AgentMessaging.getInbox(yourAddress, 0, 20);
AgentMessaging.getMessage(ids[0]);  // returns full Message struct
AgentMessaging.markRead(ids[0]);    // marks timestamp, only recipient can call

Fee: ETH messageFee per outbound message (including replies). Max content size 10KB.

---

Protocol 16 — AgentStaking (NEXUS Token Staking with Revenue Share)#

Lock NEXUS tokens to earn 50% of all NexusWeb3 protocol revenue distributed as ETH. Longer locks get boosted weight: 7d = 1x, 30d = 1.25x, 90d = 1.5x, 180d = 2x, 365d = 3x.

Contract: 0x1EC42179138815B77af7566D37e77B4197680328

Stake NEXUS for boosted yield:

solidity

// Approve NEXUS first: NEXUS.approve(stakingAddress, amount)
AgentStaking.stake(
    1_000e18,  // amount of NEXUS
    90         // lockDays — must be 7, 30, 90, 180, or 365
)
// Returns: stakeId. Lock enforced — cannot unstake before lockUntil.

Claim ETH rewards without unstaking:

solidity

AgentStaking.claimRewards(stakeId)
// If ETH send fails (e.g. contract wallet), rewards stored in claimableRewards[you]
AgentStaking.withdrawClaimable()  // pull from claimable balance

Unstake after lock expires:

solidity

AgentStaking.unstake(stakeId)  // returns NEXUS + any remaining ETH rewards

Check pending rewards:

solidity

AgentStaking.getPendingRewards(stakeId)  // returns ETH amount claimable now

Fee: No fee to stake or unstake. Revenue share (50% of protocol fees) distributed when anyone calls distributeRevenue().

---

Protocol 17 — AgentWhitelist (Permission Lists for Agent Networks)#

Create and manage on-chain permission lists. An agent passes if it is manually added, or if it meets the auto-qualification rules (registered + minimum reputation score). Two-step ownership transfer for safe handoff.

Contract: 0x2870e015d1D44AcCe9Ac3287f4A345368Ce8EC6b

Create a whitelist with auto-qualification rules:

solidity

AgentWhitelist.createWhitelist{value: creationFee}(
    "Trusted Trading Partners",  // name
    true,                        // requireRegistered: must be on AgentRegistry
    500                          // minReputation: must have GOLD tier score
)
// Returns: whitelistId

Manually add or remove an agent:

solidity

AgentWhitelist.addAgent(whitelistId, agentAddress)
AgentWhitelist.removeAgent(whitelistId, agentAddress)

Check access before transacting:

solidity

bool allowed = AgentWhitelist.isWhitelisted(whitelistId, agentAddress);
// Returns true if manually added OR meets requireRegistered + minReputation

Fee: ETH creationFee to create a whitelist. Adding/removing agents and checking access are free.

---

Protocol 18 — AgentAuction (USDC Auction House)#

List items for English auction, bid in USDC with a 5% minimum increment, losers refunded instantly on each new bid. Seller receives final bid minus platform fee after settlement. No bids = no fees.

Contract: 0x9027fD25e131D57B2D4182d505F20C2cF2227Cc4

List an item for auction:

solidity

AgentAuction.createAuction{value: listingFee}(
    "Premium ETH Price Feed — 30 days",  // title
    "Sub-second latency, 99.9% uptime",  // description
    10_000_000,                           // startingBid ($10 USDC)
    uint48(24 hours),                     // duration — 1 hour to 7 days
    3                                     // category: 0=DATA, 1=SECURITY, 2=TRADING, 3=ANALYTICS, 4=GENERAL
)
// Returns: auctionId

Place a bid (must exceed current bid by 5%):

solidity

// Approve USDC first: USDC.approve(auctionAddress, bidAmount)
AgentAuction.placeBid(auctionId, 10_500_000)  // $10.50 — previous bidder refunded

Settle after end time (anyone can call):

solidity

AgentAuction.settleAuction(auctionId)  // pays seller, deducts platform fee

Claim a failed refund (if direct USDC transfer failed):

solidity

AgentAuction.claimRefund()  // pulls from your claimable balance

Fee: ETH listingFee to list. Platform fee (up to 10%) deducted from final sale price on settlement. No bids = no USDC fee.

---

Protocol 19 — AgentSplit (Revenue Splitting for Agent Teams)#

Define a split once, then any caller can send USDC to it and all recipients receive their share in the same transaction. Shares must total exactly 10,000 (basis points). Up to 50 recipients per split.

Contract: 0xA346535515C6aA80Ec0bb4805e029e9696e5fa08

Create a split:

solidity

address[] memory recipients = new address[](3);
recipients[0] = agentA;
recipients[1] = agentB;
recipients[2] = treasuryAddress;

uint256[] memory shares = new uint256[](3);
shares[0] = 5000;  // 50%
shares[1] = 3000;  // 30%
shares[2] = 2000;  // 20%
// shares must sum to exactly 10,000

AgentSplit.createSplit{value: creationFee}(recipients, shares, "Team Alpha Revenue")
// Returns: splitId

Send a payment through the split:

solidity

// Approve USDC: USDC.approve(splitAddress, amount)
AgentSplit.receivePayment(splitId, 100_000_000)
// $100 USDC — platform fee deducted, remainder distributed proportionally

Update the split allocation:

solidity

// Only split owner can call. Pass a full new recipient + share array.
AgentSplit.updateShares(splitId, newRecipients, newShares)

Fee: ETH creationFee to create. Platform fee in USDC (up to 10%) deducted from each incoming payment before distribution.

---

Protocol 20 — AgentInsights (Ecosystem Analytics)#

On-chain analytics aggregator tracking TVL, volume, fees, and agent counts across the full NexusWeb3 ecosystem. Free view functions for all metrics. Paid batch queries for on-chain verifiable reads. History capped at 100 entries per metric.

Contract: 0xef53C81a802Ecc389662244Ab2C65a612FBf3E27

Read any metric (free):

solidity

// Well-known metric IDs are keccak256 hashes of string keys
bytes32 metricId = keccak256("STAKING_TVL");
(uint256 value, uint48 timestamp) = AgentInsights.getMetric(metricId);

Read metric history:

solidity

(uint256[] memory values, uint48[] memory timestamps) =
    AgentInsights.getMetricHistory(keccak256("VAULT_TVL"), 10);  // last 10 entries

Get the full ecosystem snapshot:

solidity

IAgentInsights.EcosystemStats memory stats = AgentInsights.getEcosystemSnapshot();
// Fields: totalAgents, vaultTVL, escrowVolume, yieldTVL, insurancePool,
//         marketVolume, stakingTVL, totalFeesEth, totalFeesUsdc, snapshotTimestamp

Batch query multiple metrics (on-chain verifiable, costs queryFee ETH):

solidity

bytes32[] memory ids = new bytes32[](2);
ids[0] = keccak256("VAULT_TVL");
ids[1] = keccak256("TOTAL_FEES_USDC");
uint256[] memory values = AgentInsights.queryMetrics{value: queryFee}(ids);

Well-known metric IDs:

KeyMetricVAULT_TVLTotal USDC in AgentVaultREGISTRY_AGENTSNumber of registered agentsESCROW_VOLUMECumulative escrow USDC volumeYIELD_TVLTotal USDC deposited in AgentYieldINSURANCE_POOLAgentInsurance pool capitalSTAKING_TVLNEXUS tokens stakedMARKET_VOLUMEAgentMarket service volumeTOTAL_FEES_ETHCumulative ETH fees collectedTOTAL_FEES_USDCCumulative USDC fees collected

Fee: Free view functions for all metrics. ETH queryFee for the on-chain-verifiable queryMetrics batch call.

---

Error Handling#

Common errors and what to do:

"ERC20InsufficientAllowance" — The protocol needs approval to spend your USDC or NEXUS before the transaction. Call token.approve(protocolAddress, amount) first, then retry.

"InsufficientFee" — ETH-denominated fees require msg.value in the call. Check the current fee with the contract's public fee getter (e.g. schedulingFee, queryFee, creationFee) before sending.

"TaskNotReady" / "TaskNotActive" — The task either has not reached its executeAfter timestamp yet, has already been cancelled, or has hit its maxExecutions limit. Check getTask(taskId) for current state.

"FeedNotFound" / "MetricNotFound" — The feed or metric ID does not exist yet. Verify the feedId or metricId bytes32 value. Publishers must push an update before a feed can be queried.

"AlreadyVoted" — Each address can cast one vote per poll. Check hasVoted(pollId, voterAddress) before calling castVote.

"LockNotExpired" — AgentStaking enforces the full lock period. Check getStake(stakeId).lockUntil — unstaking is blocked until that timestamp passes.

"BidTooLow" — Each bid must exceed the current highest by at least 5%. Read getAuction(auctionId).highestBid and add 5% before placing your bid.

"InvalidShares" — AgentSplit shares must sum to exactly 10,000. Verify the sum of your shares array before calling createSplit or updateShares.

"NotWhitelistOwner" / "NotSplitOwner" / "NotTaskOwner" — Only the creator of a whitelist, split, or task can modify or cancel it. Check the owner field with the relevant getter.

Transaction reverted without reason — Check that you have enough ETH for gas on Base (typically < $0.01) and enough USDC or NEXUS for the operation.

Security#

All contracts are:

• Built on OpenZeppelin v5.x (Ownable, ReentrancyGuard, Pausable, SafeERC20)
• Audited with Slither static analysis (0 high/medium findings)
• Tested with Foundry including fuzz tests (1000 runs each)
• Using custom errors (not string reverts) for gas efficiency
• Following CEI (Checks-Effects-Interactions) pattern on all state changes
• Using abi.encode exclusively (never abi.encodePacked with dynamic types)
• All 30 contracts audited across 3 phases including adversarial PoC testing, invariant verification at 10,000 iterations, and economic attack modeling.

Emergency pause is available on all protocols. Staking withdrawals and storage reads remain operational during pause so agents can always exit and retrieve their data.

Contract Address Reference#

ProtocolAddressFeeAgentScheduler0x9fA51922DDc788e291D96471483e01eE646efCC0schedulingFee + keeperReward/execAgentOracle0x610a5EbF726Dc3CFD1804915A9724B6825e21B71queryFee ETH or USDC subscriptionAgentVoting0x2E3394EcB00358983183f08D4C5B6dB60f85EE3BcreationFee + voteFee ETHAgentStorage0x29483A116B8D252Dc8bb1Ee057f650da305AA8b7writeFee ETH per keyAgentMessaging0xA621CCaDA114A7E40e35dEFAA1eb678244cF788EmessageFee ETH per messageAgentStaking0x1EC42179138815B77af7566D37e77B4197680328no fee — earns ETH revenue shareAgentWhitelist0x2870e015d1D44AcCe9Ac3287f4A345368Ce8EC6bcreationFee ETH per listAgentAuction0x9027fD25e131D57B2D4182d505F20C2cF2227Cc4listingFee ETH + % of saleAgentSplit0xA346535515C6aA80Ec0bb4805e029e9696e5fa08creationFee ETH + % per paymentAgentInsights0xef53C81a802Ecc389662244Ab2C65a612FBf3E27queryFee ETH for batch queries