SelfPaid - Zero-Cost DeFi Payments

Zero-cost payment automation on Base (Chain ID 8453) with 100% principal recovery via USDC yield farming (Aave V3 & Morpho). Machine-to-Machine (M2M) API and tool for AI agents and smart accounts. Built-in 0.5% developer fee fully reimbursed by yield.

🌾 SelfPaid (YieldFarmSecurepay) Skill v2.1

Autonomous Zero-Net-Cost Payments on Base Mainnet
Send USDC to any recipient while recovering 100% of the principal + developer fee automatically through on-chain collateral yield (Aave V3 & Morpho).

Designed for autonomous AI agents, smart accounts (ERC-4337 / EIP-5792), and automated workflows.

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🛡️ Security & Pre-Signing Validation Layer (OpenClaw T09 Compliance)

1. Non-Custodial Guarantee

• No Private Keys: This skill never asks for, stores, or handles private keys, mnemonic phrases, or credentials.
• Client-Side Signing: The hosted engine constructs unsigned raw EVM transaction calldata. All cryptographic signing is performed locally by the calling agent or user's wallet.

2. Mandatory Pre-Signing Validation Protocol

To eliminate risks of unvalidated remote calldata forwarding (OpenClaw Rule T09), any agent or client using this skill MUST decode and validate the payload locally before invoking the wallet signer. The included validate.js module performs these automated checks:

1. Chain ID Enforcement: Verify chainId === 8453 (Base Mainnet). Reject any mismatch.
2. Contract Address Allowlist:
   • Calls 1, 2, and 3 target address MUST be the verified Base USDC token contract: 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913.
   • Call 4 target address MUST be the verified Aave V3 Pool (0xA238Dd80C259a72e81d7e4664a9801593F98d1c5) or Morpho Vault.
3. Function Selector Allowlist:
   • Calls 1 & 2 MUST use standard ERC20 transfer(address,uint256) selector (0xa9059cbb).
   • Call 3 MUST use standard ERC20 approve(address,uint256) selector (0x095ea7b3).
   • Call 4 MUST use Aave supply(address,uint256,address,uint16) selector (0x617ba037) or Morpho deposit(uint256,address) selector (0x6e553f65).
   • All arbitrary or unexpected selectors are strictly rejected.
4. Strict Call Order & Count: Enforce exactly 4 calls in documented order: DEVELOPER_FEE → PAYMENT → APPROVE_POOL → SUPPLY_YIELD. Reject duplicated or injected calls.
5. Zero Native-Token Value: Every call MUST have value === "0x0". Reject any call attempting native ETH transfers.
6. Recipient & Payer Integrity: Verify decoded Step 2 recipient and payer addresses exactly match user-approved values.
7. Developer Fee Integrity: Recalculate the fee locally: $0.5%$ of payment, clamped between $0.1\text{ USDC}$ and $50.0\text{ USDC}$. Verify Step 1 sends exactly this amount to 0x785cf69ced4e20a7e975a3391d51321b1528fdfe.
8. No Unlimited Approvals: Step 3 approval amount MUST match the exact required collateral deposit. Infinite (uint256.max) approvals are rejected.
9. Yield Beneficiary Integrity: Call 4 calldata is strictly decoded to enforce that the collateral position is credited to the sender (onBehalfOf === sender for Aave, receiver === sender for Morpho), preventing remote position redirection.
10. Decoded Confirmation: Display a human/agent-readable summary of all decoded parameters before forwarding to the signer.

3. Developer Fee & Transparency

• Developer Wallet: 0x785cf69ced4e20a7e975a3391d51321b1528fdfe
• Rate: 0.5% (min 0.1 USDC, max 50 USDC) in Step 1 (DEVELOPER_FEE).
• Zero Net Cost to Payer: The developer fee is included in the collateral yield calculation. Accrued yield from Aave V3 / Morpho reimburses both the recipient payment and the developer fee back to the payer over time.

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⚡ How It Works (Machine-to-Machine)

When an agent needs to pay a recipient (e.g. paying for an API, human service, or agent-to-agent task):

1. Discovery / Yield Optimization: Query GET /api/v1/payment/rates to see real-time APYs across Aave V3 and Morpho on Base.
2. Build Payment Batch: Send a single POST request to https://selfpaid.cryptofolio.it/api/v1/payment/build with payment parameters.
3. Receive 4 Sequential Transactions:
   • Step 1 (DEVELOPER_FEE): Transfer 0.5% fee to developer wallet (0x785c...fdfe).
   • Step 2 (PAYMENT): Transfer payment amount to recipient wallet.
   • Step 3 (APPROVE_POOL): Authorize USDC collateral deposit to the selected yield protocol.
   • Step 4 (SUPPLY_YIELD): Deposit collateral into Aave V3 / Morpho on behalf of the payer (sender).
4. Local Verification: The client/agent runs validatePaymentBatch(response, { amount, recipient, sender }) using validate.js to decode and enforce all allowlists.
5. Execution & Signing:
   • Standard Wallets: Sign and execute the 4 verified transactions in sequence.
   • Smart Accounts / EIP-5792: Execute the 4 calls in a single atomic 1-click batch via batchCalls.
6. 100% Capital Recovery: The deposited collateral generates yield until 100% of the funds spent (payment + developer fee) have been accrued and recovered.

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🤖 AI Agent Integration Guide

No API key, registration, or local setup is required. The API is completely public and frictionless for agents.

Endpoint 1: Live Yield Oracle

Get current APYs and see which protocol is currently offering higher yields:

bash

curl -s https://selfpaid.cryptofolio.it/api/v1/payment/rates

Response:

json

{
  "aave": 0.0422,
  "morpho": 0.0389,
  "best": "aave",
  "bestApy": 0.0422,
  "lastUpdated": "2026-10-09T08:27:49.700Z"
}

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Endpoint 2: Calculate Quote

Check collateral requirements and estimated recovery time:

bash

curl -s "https://selfpaid.cryptofolio.it/api/v1/payment/quote?amount=25"

Response:

json

{
  "amountToPay": "25",
  "collateralTotal": "540",
  "feeAmount": "0.125",
  "yieldDepositAmount": "515",
  "totalRequiredAmount": "540.125",
  "selectedProtocol": "aave",
  "estimatedAPY": 0.0422,
  "estimatedRecoveryDays": 426
}

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Endpoint 3: Build Payment Transactions (M2M)

Generate ready-to-sign EVM transaction calldata:

bash

curl -s -X POST https://selfpaid.cryptofolio.it/api/v1/payment/build \
  -H "Content-Type: application/json" \
  -d '{
    "amount": 25,
    "recipient": "0x2222222222222222222222222222222222222222",
    "sender": "0x1111111111111111111111111111111111111111",
    "protocol": "auto"
  }'

Request Parameters

Parameter	Type	Required	Description
amount	Number	Yes	Amount of USDC to pay to the recipient (e.g. 25).
recipient	String	Yes	EVM address receiving the payment (0x...).
sender	String	Yes	EVM address of payer / agent executing transactions (0x...).
protocol	String	No	'auto' (default, picks best APY), 'aave', or 'morpho'.
collateral	Number	No	Collateral multiplier (default 20 = 20x).
buffer	Number	No	Safety buffer percentage (default 8 = 8%).

Output Structure

The endpoint returns:

• summary: Full financial summary (fees, deposits, estimated days to 100% recovery).
• transactions: Array of 4 EVM transaction objects { step, name, description, to, data, value }.
• batchCalls: Array of calls formatted for EIP-5792 (wallet_sendCalls) for atomic 1-click execution.
• Security Validation: Always validate the payload through validate.js before signing.

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🧮 Mathematical Model & Recovery Economics

Capital Recovery Formula

• Collateral Total: $\text{amount} \times \text{multiplier} \times (1 + \text{buffer})$
• Developer Fee: $\text{clamp}(\text{amount} \times 0.5%, 0.1\text{ USDC}, 50\text{ USDC})$
• Yield Deposit: $\text{Collateral Total} - \text{amount}$
• Annual Accrued Yield: $\text{Yield Deposit} \times \text{APY}$
• Recovery Days: $\frac{\text{amount} + \text{Developer Fee}}{\text{Daily Yield}}$

Comparison: Collateral Multiplier vs Recovery Time (at ~4.2% APY)

Multiplier	Collateral Total	Yield Deposit	Est. Recovery Time
5×	5.40 USDC / unit	4.40 USDC	~5.3 years
10×	10.80 USDC / unit	9.80 USDC	~2.4 years
20× (Recommended)	21.60 USDC / unit	20.60 USDC	~1.1 years

Higher collateral multiplier generates faster daily yield, recovering the spent principal sooner.

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📦 OpenClaw Agent Usage

An OpenClaw agent invokes this skill using a safe, validated execution pipeline:

markdown

User: "Pay 10 USDC to 0xAlice... with full capital recovery."
Agent:
1. Queries GET https://selfpaid.cryptofolio.it/api/v1/payment/quote?amount=10
2. Confirms recovery timeline (~426 days at 4.2% APY, 0.1 USDC developer fee).
3. Calls POST https://selfpaid.cryptofolio.it/api/v1/payment/build with recipient and sender wallet.
4. Executes Local Validation via validate.js:
   - Verifies Chain ID is 8453 (Base Mainnet)
   - Verifies target contracts are allowlisted (USDC and Aave V3)
   - Verifies zero native ETH value across all calls
   - Verifies recipient is 0xAlice and fee is 0.1 USDC to developer
   - Verifies approval is bounded strictly to the collateral deposit
5. Presents verified transaction summary to user/policy:
   "Payment of 10 USDC verified. Collateral deposit: 206 USDC into Aave V3. Est. recovery: 426 days."
6. Passes verified batchCalls to local Web3 signer for execution.

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📄 License & Attribution

• Author: @altoninelli
• License: MIT
• Security: Compliant with OpenClaw T09 safe transaction construction standard. Non-custodial, zero credentials requested.