skillet

BSC (Binance Smart Chain) trading on PancakeSwap - wallet registration, swaps, discover tokens and pairs, funding.

BSC PancakeSwap Trading Skill

This skill lets the AI agent create a BSC wallet (private key + address saved in one file), discover which tokens and swaps are available on PancakeSwap, swap tokens, and receive top-ups from the user. The agent is not limited to specific tokens — it can resolve token addresses and check which pairs have liquidity.

Configuration (BSC Mainnet)

bash

export BSC_RPC_URL="https://bsc-dataseed1.binance.org"
export BSC_CHAIN_ID=56

# PancakeSwap V2 (BSC mainnet)
export PANCAKE_ROUTER="0x10ED43C718714eb63d5aA57B78B54704E256024E"
export WBNB="0xbb4CdB9CBd36B01bD1cBaEBF2De08d9173bc095c"

Block explorer: https://bscscan.com

PancakeSwap UI: https://pancakeswap.finance/swap?chain=bsc

Optional: switch to testnet

For testnet (tBNB, tCHR, etc.), use:

bash

export BSC_RPC_URL="https://data-seed-prebsc-1-s1.binance.org:8545"
export BSC_CHAIN_ID=97
export PANCAKE_ROUTER="0xD99D1c33F9fC3444f8101754aBC46c52416550D1"
export WBNB="0xae13d989dac2f0debff460ac112a837c89baa7cd"

Prerequisite: Node.js 18+ with ethers (v6):

bash

npm install ethers
# or: pnpm add ethers

---

1. Registration — Create Wallet and Save Keys to One File

The agent needs one file that stores both the private key and public address so it can sign transactions. Create it once and reuse it.

Option A: Using Node.js (recommended)

Run this script to generate a new wallet and write it to a file:

bash

node -e "
const fs = require('fs');
const path = require('path');
const { ethers } = require('ethers');
const wallet = ethers.Wallet.createRandom();
const dir = process.env.HOME + '/.config/bsc_agent';
fs.mkdirSync(dir, { recursive: true });
const file = dir + '/wallet.json';
fs.writeFileSync(file, JSON.stringify({
  privateKey: wallet.privateKey,
  address: wallet.address,
  publicKey: wallet.publicKey
}, null, 2));
console.log('Wallet saved to ' + file);
console.log('Address: ' + wallet.address);
"

Default file location: ~/.config/bsc_agent/wallet.json.

File format (wallet.json):

json

{
  "privateKey": "0x...",
  "address": "0x...",
  "publicKey": "0x..."
}

• privateKey — Used to sign transactions. Keep this file secret and only on the agent's machine.
• address — The agent's BSC account. User sends BNB/tokens to this address to top up.
• publicKey — Optional; derived from private key.

Option B: Custom path

To use a different path, set the output file in the script:

bash

export BSC_WALLET_FILE="$HOME/.config/bsc_agent/wallet.json"
# Then in the script, write to process.env.BSC_WALLET_FILE

After registration

1. Read address and publicKey from wallet.json.
2. Tell the user: My BSC address for top-ups is: <address>
3. User must send native BNB (for gas) and any tokens they want the agent to swap to this address.
4. Register public key on Chromia: Link your BSC wallet public key to your ClawChain agent account to enable tracking EVM events on Chromia.

---

1.5. Register Public Key on Chromia

After creating your BSC wallet, register the public key on Chromia to link your PancakeSwap wallet to your ClawChain agent account. This enables tracking EVM events on your Chromia chain.

Prerequisites

• You must have a registered agent account on ClawChain (Chromia)
• You must have an authenticated session (FT4 session from MetaMask or Chromia Vault)
• Your wallet.json file must exist with publicKey (required) and optionally address

Registration Steps

Option A: Using Chromia CLI

bash

# Set your ClawChain configuration
export CLAWCHAIN_BRID="9D728CC635A9D33DAABAC8217AA8131997A8CBF946447ED0B98760245CE5207E"
export CLAWCHAIN_NODE="https://chromia.01node.com:7740"

# Read wallet info
WALLET_FILE="$HOME/.config/bsc_agent/wallet.json"
PUBLIC_KEY=$(cat $WALLET_FILE | grep -o '"publicKey": "[^"]*' | cut -d'"' -f4)
ADDRESS=$(cat $WALLET_FILE | grep -o '"address": "[^"]*' | cut -d'"' -f4)

# Register public key on Chromia
chr tx register_evm_public_key \
  "pancakeswap" \
  "$PUBLIC_KEY" \
  "BSC" \
  56 \
  "$ADDRESS" \
  --ft-auth \
  --secret ~/.config/clawchain/credentials.json \
  -brid $CLAWCHAIN_BRID \
  --api-url $CLAWCHAIN_NODE \
  --await

Arguments: wallet_type public_key chain network_id address

Network IDs:

• BSC Mainnet: 56
• BSC Testnet: 97
• Ethereum Mainnet: 1
• Ethereum Goerli: 5
• Polygon Mainnet: 137

Note: If you don't have an address, use "" (empty string) for the last parameter.

Option B: Using JavaScript/TypeScript

If you're integrating this into a web application with an authenticated FT4 session:

javascript

const fs = require('fs');
const walletData = JSON.parse(fs.readFileSync('~/.config/bsc_agent/wallet.json', 'utf8'));

// Assuming you have a Chromia session object (from @chromia/ft4)
const result = await session.call({
  name: 'register_evm_public_key',
  args: [
    'pancakeswap',              // wallet_type
    walletData.publicKey,      // public_key (required)
    'BSC',                      // chain
    56,                         // network_id (56 for BSC mainnet, 97 for testnet)
    walletData.address || ""   // address (optional)
  ]
});

console.log('Public key registered:', result);

Query Registered Public Keys

To check which public keys are registered for your agent:

bash

# Get all registered public keys for an agent
chr query get_evm_public_keys 'agent_name=your_agent_name' \
  -brid $CLAWCHAIN_BRID --api-url $CLAWCHAIN_NODE

# Get specific public key by wallet type
chr query get_evm_public_key_by_type \
  'agent_name=your_agent_name' \
  'wallet_type=pancakeswap' \
  -brid $CLAWCHAIN_BRID --api-url $CLAWCHAIN_NODE

Error Handling

• "Public key already registered": The public key is already registered for this agent. Query existing keys to verify.
• "Public key is required for EIF event tracking": You must provide a public key.
• "Invalid public key format": Public key must start with 0x and be at least 66 characters (0x + 64 hex chars).
• "Agent not found": Ensure your agent account exists on ClawChain.
• Authentication errors: Ensure you have a valid FT4 session authenticated with your Chromia account.

---

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2. How the User Can Top Up the Agent Account

The agent does not have an "account" on a server — it has a BSC address (from wallet.json). Fund the agent by sending BNB and tokens to that address:

Get BNB for gas and swaps

1. Buy BNB on an exchange or bridge from another chain.
2. Send BNB to the agent address: <address> from wallet.json.
3. Add BSC Mainnet in MetaMask (Chain ID 56, RPC above), then transfer BNB to the agent.

Get tokens

• Send any BEP-20 token to <address>. The agent can swap via PancakeSwap if a pair exists (e.g. USDT/BNB, BUSD/BNB).

Check balance

• Native (BNB): provider.getBalance(address)
• Any BEP-20 token: call balanceOf(address) on the token contract.

---

3. Discovering Available Tokens and Swaps

The agent must support any BEP-20 token and determine which swaps are possible.

Which tokens are available

• By contract address: Any BEP-20 token is identified by its contract address. Accept token addresses from the user or from token lists.
• Resolve symbol and decimals: Call the token contract (ERC-20/BEP-20):
  • symbol() → e.g. "USDT", "WBNB"
  • decimals() → use for amount math and display (e.g. 18 or 6)
  • name() → full name (optional)
• Token lists (optional): PancakeSwap and BSC publish token lists; the agent can also accept any user-provided contract address.
• Native gas token: BNB is the chain native token; the wrapped version is WBNB (address in config). Use WBNB in router paths.

Which swaps are available

• Get the Factory: Call the router's factory() (read-only) to get the PancakeSwap V2 Factory address.
• Check if a pair exists: Call factory.getPair(tokenA, tokenB). If the result is the zero address (0x000...), no pair exists. Otherwise it is the pair contract address.
• Check liquidity: On the pair contract, call getReserves(). If both reserves are > 0, the pair has liquidity and that swap is available.
• Quote before swapping: Use the router's getAmountsOut(amountIn, path) (read-only). If the call reverts or returns zero for the output amount, the swap is not feasible (no liquidity or invalid path).
• Multi-hop paths: If there is no direct A–B pair, try a path via WBNB: [tokenA, WBNB, tokenB]. Call getAmountsOut(amountIn, path); if it succeeds and returns a positive amount, the swap is available.
• Optional: PancakeSwap API or subgraph can list pairs for a token; the agent may use these to discover pairs in addition to on-chain checks.

---

4. Making a Trade (Swap on PancakeSwap)

The agent uses the private key from wallet.json to sign a swap transaction and sends it to BSC.

PancakeSwap V2 router (BSC mainnet)

Contract	Address
Router	0x10ED43C718714eb63d5aA57B78B54704E256024E
WBNB	0xbb4CdB9CBd36B01bD1cBaEBF2De08d9173bc095c

Common swap methods

Method	Use case
swapExactETHForTokens	Swap exact BNB for tokens (min amount out)
swapExactTokensForETH	Swap exact tokens for BNB
swapExactTokensForTokens	Swap exact token A for token B
swapTokensForExactTokens	Swap tokens for exact amount of token B

Swap flow (any token pair with liquidity)

1. Load wallet from wallet.json (privateKey + address).
2. Connect to BSC: new ethers.JsonRpcProvider(BSC_RPC_URL) (mainnet: chain id 56).
3. Resolve tokens: Use token contract addresses (from user or discovery). For native BNB use WBNB in the path.
4. Check swap availability: Call router getAmountsOut(amountIn, path). If it reverts or returns zero, try a multi-hop path (e.g. [tokenA, WBNB, tokenB]) or inform the user the pair has no liquidity.
5. Build path: e.g. BNB → token: [WBNB, tokenAddress]; token → BNB: [tokenAddress, WBNB]; token → token: [tokenA, WBNB, tokenB] (or direct if pair exists).
6. Get router contract (address above), ABI for swapExactETHForTokens, swapExactTokensForETH, or swapExactTokensForTokens.
7. Deadline: Math.floor(Date.now() / 1000) + 300 (e.g. 5 minutes).
8. amountOutMin: from getAmountsOut(amountIn, path) then apply slippage (e.g. 1% = amountOut * 0.99).
9. Sign and send: For BNB → token use { value: amountInWei }; for token → BNB or token → token, approve router for the token first, then call the swap.

Slippage

• amountOutMin = expected output × (1 - slippage). E.g. 1% slippage → multiply by 0.99.
• For volatile pairs use 2–5%.

Token decimals

• BNB has 18 decimals. 1 BNB = 1e18 wei.
• Many BEP-20 tokens use 18 decimals; USDT/USDC often use 6. Check the token contract or docs.

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5. Command / Script Patterns for the Agent

Read wallet (do not expose private key in logs)

• Read ~/.config/bsc_agent/wallet.json (or BSC_WALLET_FILE).
• Use address when telling the user where to top up.
• Use privateKey only inside the signing process (ethers Wallet).

Execute swap (high level)

1. Load wallet.json.
2. Create ethers.Wallet(privateKey, provider).
3. Build router call (e.g. swapExactETHForTokens) with path, deadline, amountOutMin.
4. Send transaction: tx = await router.swapExactETHForTokens(...); await tx.wait().
5. Return tx hash to user: https://bscscan.com/tx/<hash>.

Get quote before swapping

• Call router getAmountsOut(amountIn, path) (read-only) to get expected amountOut, then compute amountOutMin with slippage.

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6. Example Token Addresses (BSC Mainnet)

Symbol	Address	Notes
WBNB	0xbb4CdB9CBd36B01bD1cBaEBF2De08d9173bc095c	Native wrapped; use in paths
USDT	0x55d398326f99059fF775485246999027B3197955	Stablecoin
BUSD	0xe9e7CEA3DedcA5984780Bafc599bD69ADd087D56	Stablecoin

Do not limit to these. The agent should accept any BEP-20 address and discover availability via getPair / getReserves and getAmountsOut (see §3). If a pair has no liquidity, add liquidity via the PancakeSwap UI or use another token pair.

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7. Security Notes

• wallet.json contains the private key. Restrict access: chmod 600 ~/.config/bsc_agent/wallet.json.
• Use this wallet only for the agent and only with amounts you accept to lose if the machine or file is compromised.
• Prefer a dedicated BSC wallet; do not reuse a wallet that holds large funds elsewhere.

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8. Errors

Error	Meaning / action
insufficient funds	Not enough BNB for gas or not enough token/BNB for the swap. User should top up.
execution reverted: PancakeRouter: INSUFFICIENT_OUTPUT_AMOUNT	Slippage too low; increase or retry.
execution reverted: PancakeRouter: EXPIRED	Deadline passed; rebuild tx with new deadline.
nonce too low	Reuse of nonce; wait and retry or refresh nonce from chain.

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9. Links

• PancakeSwap (BSC mainnet): https://pancakeswap.finance/swap?chain=bsc
• PancakeSwap V2 docs: https://docs.pancakeswap.finance/developers/smart-contracts/pancakeswap-exchange/v2-contracts
• BSC explorer: https://bscscan.com