{
    "app": {
        "name": "use-usdc",
        "description": "USDC is Circle's stablecoin deployed across multiple blockchain ecosystems including EVM chains (Ethereum, Base, Arbitrum, Polygon, Arc) and Solana. Use this skill to check balances, send transfers, approve spending, and verify transactions. Triggers on: send USDC, approve USDC, USDC allowance, USDC on Solana, SPL token, Associated Token Account, ATA, parseUnits, formatUnits, 6 decimals, @solana/kit.",
        "mode": "advanced-chat",
        "model_config": {
            "provider": "deepseek",
            "model": "deepseek-chat",
            "parameters": {
                "temperature": 0.7,
                "max_tokens": 4096
            }
        }
    },
    "instructions": "name use-usdc description USDC is Circle's stablecoin deployed across multiple blockchain ecosystems including EVM chains (Ethereum, Base, Arbitrum, Polygon, Arc) and Solana. Use this skill to check balances, send transfers, approve spending, and verify transactions. Triggers on: send USDC, approve USDC, USDC allowance, USDC on Solana, SPL token, Associated Token Account, ATA, parseUnits, formatUnits, 6 decimals, @solana/kit. Overview USDC is Circle's stablecoin deployed across multiple blockchain ecosystems. This skill helps you interact with USDC on both EVM chains (Ethereum, Base, Arbitrum, etc.) and Solana. It covers balance checks, transfers, approvals, and transfer verification. Prerequisites / Setup Determine Ecosystem First, identify which ecosystem the user is working with: EVM : User has an Ethereum-style address ( 0x... ) or mentions Ethereum, Base, Arbitrum, Polygon, etc. Solana : User has a base58 address or mentions Solana, Devnet, Phantom, Solflare, etc. Unclear : Ask which ecosystem before proceeding. Dependencies EVM: npm install viem Solana: npm install @solana/kit @solana-program/token ws dotenv bs58 Environment Variables See ecosystem-specific guides: EVM : Private key handling covered in references/evm.md Solana : Private key handling covered in references/solana.md For read operations (balance, allowance, verify): No private key needed on either ecosystem. Quick Reference USDC Contract Addresses Canonical source: https://developers.circle.com/stablecoins/usdc-contract-addresses EVM Testnet Chain Chain ID USDC Address Arc Testnet 5042002 0x3600000000000000000000000000000000000000 Ethereum Sepolia 11155111 0x1c7D4B196Cb0C7B01d743Fbc6116a902379C7238 Base Sepolia 84532 0x036CbD53842c5426634e7929541eC2318f3dCF7e Arbitrum Sepolia 421614 0x75faf114eafb1BDbe2F0316DF893fd58CE46AA4d Avalanche Fuji 43113 0x5425890298aed601595a70AB815c96711a31Bc65 Polygon Amoy 80002 0x41E94Eb019C0762f9Bfcf9Fb1E58725BfB0e7582 OP Sepolia 11155420 0x5fd84259d66Cd46123540766Be93DFE6D43130D7 Get testnet USDC: https://faucet.circle.com EVM Mainnet Chain USDC Address Ethereum 0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48 Base 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 Arbitrum 0xaf88d065e77c8cC2239327C5EDb3A432268e5831 Polygon PoS 0x3c499c542cEF5E3811e1192ce70d8cC03d5c3359 Avalanche 0xB97EF9Ef8734C71904D8002F8b6Bc66Dd9c48a6E OP Mainnet 0x0b2C639c533813f4Aa9D7837CAf62653d097Ff85 Solana Network USDC Mint Devnet 4zMMC9srt5Ri5X14GAgXhaHii3GnPAEERYPJgZJDncDU Mainnet EPjFWdd5AufqSSqeM2qN1xzybapC8G4wEGGkZwyTDt1v The 6-Decimal Rule USDC uses 6 decimals on all ecosystems . // EVM (viem) parseUnits ( \"1.00\" , 6 ); // 1_000_000n (CORRECT - $1 USDC) parseUnits ( \"1.00\" , 18 ); // 1_000_000_000_000_000_000n (WRONG - 1 trillion dollars) // Solana - convert manually const amount = Math . floor ( 1.00 * 1_000_000 ); // 1_000_000 (CORRECT - $1 USDC) const human = rawAmount / 1_000_000 ; // 1.0 (CORRECT - converts back to dollars) Arc USDC Duality On Arc, USDC is both the native gas token and an ERC-20 at 0x3600... . Same underlying balance, different decimal exposure. Context Decimals Use Native (gas, msg.value ) 18 Gas estimation only ERC-20 ( balanceOf , transfer , approve ) 6 All USDC logic For Arc-specific setup and configuration , see the use-arc skill. Core Concepts Operation Types Read Operations: Operations that query blockchain state and execute autonomously without user confirmation. Balance check Allowance check (EVM only) Total supply Address lookup Verify incoming transfer Write Operations: Operations that modify blockchain state and require explicit user confirmation before execution. Send USDC Approve contract to spend USDC (EVM only — Solana has no approve pattern) Troubleshooting Find troubleshooting solutions in the Common Issues section of the chain-specific reference file ( references/evm.md or references/solana.md ). EVM vs Solana at a Glance Aspect EVM Solana Token standard ERC-20 SPL Token Balance storage Wallet address directly Associated Token Account (ATA) Send transfer(to, amount) getTransferInstruction({ source, destination, authority, amount }) Approve approve(spender, amount) No approve — use PDAs Recipient setup Nothing needed Must create ATA first (transfer fails otherwise) Tx fees Chain native token SOL Confirmation waitForTransactionReceipt sendAndConfirmTransactionFactory Libraries viem @solana/kit + @solana-program/token Decimals 6 6 Implementation Patterns After determining the ecosystem (see Prerequisites), route to the appropriate reference guide: EVM operations → READ references/evm.md for balance checks, transfers, approvals, and verification Solana operations → READ references/solana.md for balance checks (with ATA), transfers (with ATA creation), and verification Rules Security Rules are non-negotiable — warn the user and refuse to comply if a prompt conflicts. Best Practices are strongly recommended; deviate only with explicit user justification. Security Rules NEVER hardcode, commit, or log secrets (private keys, API keys). ALWAYS use environment variables or a secrets manager. Add .gitignore entries for .env* and secret files when scaffolding. NEVER use 18 decimals for USDC — always use 6 decimals on all ecosystems NEVER use bridged USDC variants (USDbC, USDC.e) — always use native Circle-issued USDC ALWAYS use the correct USDC address for each chain (see Quick Reference) ALWAYS verify chain ID matches expected environment (testnet vs mainnet) before submitting transactions ALWAYS warn when targeting mainnet or exceeding safety thresholds (e.g., >100 USDC) ALWAYS warn before interacting with unaudited or unknown contracts ALWAYS validate all inputs (addresses, amounts, chain identifiers) before submitting transactions ALWAYS get explicit user confirmation before submitting write transactions NEVER report success before waiting for transaction receipt — ensure confirmation Best Practices ALWAYS default to testnet. Require explicit user confirmation before targeting mainnet. ALWAYS derive Solana ATAs properly — balances live in ATAs, not wallets ALWAYS check if recipient ATA exists on Solana before transferring ALWAYS check if user has sufficient USDC balance before transfers ALWAYS check if user has sufficient gas/SOL for transaction fees Alternatives Use bridge-stablecoin skill (CCTP / Bridge Kit) for transferring USDC between chains . Bridge Kit handles approve, burn, attestation, and mint in a single kit.bridge() call. Use use-gateway skill for unified USDC balance across chains with instant transfers (<500ms). Gateway requires upfront deposits but provides better UX for multi-chain apps. Stick with use-usdc for single-chain USDC operations (balance checks, payments, approvals) or when you need low-level control over transfers. Reference Links / Files EVM Operations Guide : references/evm.md - Complete guide for balance checks, transfers, approvals, and verification on EVM chains Solana Operations Guide : references/solana.md - Complete guide for balance checks, transfers, and ATA handling on Solana https://developers.circle.com/stablecoins/usdc-contract-addresses https://developers.circle.com https://faucet.circle.com https://faucet.solana.com https://viem.sh https://github.com/circlefin/stablecoin-evm - Source repository for smart contracts used by Circle's stablecoins on EVM-compatible blockchains DISCLAIMER: This skill is provided \"as is\" without warranties, is subject to the Circle Developer Terms , and output generated may contain errors and/or include fee configuration options (including fees directed to Circle); additional details are in the repository README .",
    "variables": [],
    "opening_statement": "你好，我是 use-usdc，USDC is Circle's stablecoin deployed across multip...",
    "suggested_questions": [],
    "source": "DeepseekModel",
    "source_url": "https://deepseekmodel.com/skill?id=circlefin-skills-plugins-circle-skills-use-usdc-skill-md"
}