PayGents

Accept crypto payments through your AI agent. Generate wallet deeplinks, verify on-chain, issue receipts — no backend, no API keys.

Quick Start

Send 10 USDC on Base:

scripts/evm-payment-link.sh --to 0xRECIPIENT --amount 10 --chain-id 8453

Verify the payment:

scripts/evm-verify-tx.sh --chain-id 8453 --from 0xSENDER --to 0xRECIPIENT --asset ERC20 --amount 10 --blocks 50

Check a wallet balance:

scripts/evm-balance.sh --address 0xADDRESS

That's it. No API keys, no backend, no custody.

Flow

1. Agent collects payment details (recipient, amount, chain, token).
2. Agent runs the link generator script → gets a MetaMask deeplink.
3. Agent sends the link to the user.
4. User taps → MetaMask opens with pre-filled transfer → user approves.
5. User confirms "sent" → agent verifies the tx on-chain.

Wallet Detection

Before generating a link, the agent should know which wallet the user has. Ask once, remember forever.

Supported wallets with native deeplinks:

Not supported (no send deeplinks):

• Rabby — only has in-app browser, no direct send deeplink
• Coinbase Wallet — only has dapp browser deeplink, no direct send
• Phantom — requires encrypted handshake, not a simple URL

If the user's wallet isn't supported, default to MetaMask (most common) or let them know.

Store the user's wallet preference so you don't ask again. The agent should note the preference in its local session context (e.g. memory file). The user can change or clear this at any time by telling the agent.

Inputs Required

Commands

Generate Payment Link

ERC20 (USDC) — MetaMask:

scripts/evm-payment-link.sh \
  --to 0x1234...5678 \
  --amount 10 \
  --chain-id 8453

Native ETH — Trust Wallet:

scripts/evm-payment-link.sh \
  --to 0x1234...5678 \
  --amount 0.01 \
  --asset ETH \
  --chain-id 11155111 \
  --wallet trust

Output is JSON with:

• intent — structured payment details
• deeplink — MetaMask deeplink URL
• messageTemplate — ready-to-send message for the user

Verify Transaction

After the user says "sent", verify on-chain:

scripts/evm-verify-tx.sh \
  --chain-id 11155111 \
  --from 0xSENDER \
  --to 0xRECIPIENT \
  --asset ETH \
  --amount 0.001 \
  --blocks 50

Returns the matching tx hash if found, or "not found".

Supported Chains

User Message Pattern

When sending the link, always include:

1. Amount + token + chain
2. Recipient (truncated)
3. "Tap to open MetaMask and approve"
4. "Reject if recipient or amount doesn't match"

Check Wallet Balance

Query native + major ERC20 balances across all supported chains:

# All chains at once
scripts/evm-balance.sh --address 0x1234...5678

# Single chain
scripts/evm-balance.sh --address 0x1234...5678 --chain-id 8453

Returns JSON with native balance + USDC, USDT, WETH, WBTC, DAI per chain.

Supported chains: Ethereum, Base, Polygon, Arbitrum, Optimism, BNB Chain, Sepolia, Base Sepolia.

No API key needed — uses public RPCs directly.

Generate Receipt

After a transaction is verified, generate a structured receipt:

scripts/evm-receipt.sh \
  --tx-hash 0xabc123... \
  --chain-id 8453 \
  --memo "order-42" \
  --merchant "Cool Store"

Options:

• --format json | markdown | both (default: both)
• --out <directory> — save receipt files to disk (JSON + markdown)
• --memo — order ID or note
• --merchant — merchant/payee name

Output includes: status, amount, token, from/to, gas fee, block, explorer link, timestamp.

The receipt can be sent to the user as a confirmation message, saved for bookkeeping, or forwarded to a merchant.

RPC Configuration

By default, scripts use public RPC endpoints. You can override them for privacy or reliability:

Option 1 — Environment variables (highest priority):

export RPC_1="https://my-private-eth-node.com"
export RPC_8453="https://my-base-rpc.com"

Option 2 — Config file (copy config.example.json → config.json):

{
  "rpc": {
    "1": "https://my-private-eth-node.com",
    "8453": "https://my-base-rpc.com"
  }
}

Option 3 — Public fallbacks (default, no setup needed): Used automatically if no env var or config is set. Public providers (e.g. eth.llamarpc.com) will see your wallet addresses and tx hashes.

Resolution order: env var RPC_<chainId> → config.json → public fallback.

Security & Privacy

• The wallet is the trust boundary — agent cannot force-execute.
• Verification checks the actual on-chain receipt, not user claims.
• Never store or handle private keys.
• RPC privacy: If using public fallback RPCs, third-party providers will see wallet addresses and tx hashes you query. Set your own RPCs via env vars or config.json for privacy.
• Wallet preference: The agent may store the user's preferred wallet (metamask/trust) in its memory. This is only the wallet app name, no keys or sensitive data. The user can ask the agent to clear it at any time.