evm-swiss-knife

Original：🇺🇸 English

Translated

Interact with EVM-compatible blockchains using Foundry's cast tool for querying balances, calling contracts, sending transactions, and blockchain exploration. Use when needing to interact with Ethereum Virtual Machine networks via command-line, including reading contract state, sending funds, executing contract functions, or inspecting blockchain data.

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Sourcekukapay/crypto-skills

Added on2026-02-07

NPX Install

npx skill4agent add kukapay/crypto-skills evm-swiss-knife

SKILL.md Content

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EVM Swiss Knife

This skill enables interaction with EVM-compatible blockchains through Foundry's

cast

command-line tool. It covers common blockchain operations like balance queries, contract calls, transaction sending, and network inspection.

Installation

To use this skill, you need Foundry installed, which provides the

cast

command.

Follow the official installation guide: https://getfoundry.sh/introduction/installation

Quick Install (Linux/Mac)

Install Foundryup:

bash

curl -L https://foundry.paradigm.xyz | bash

Source your shell configuration or start a new terminal:
bash
```
source ~/.bashrc  # or ~/.zshrc
```
Install Foundry:
bash
```
foundryup
```
Verify installation:
bash
```
cast --version
```

For other platforms or detailed instructions, see the full guide at https://getfoundry.sh/introduction/installation

Prerequisites

Foundry installed (
```
cast
```
command available)
RPC endpoint configured (via
```
--rpc-url
```
or environment variables)
Private key for transaction operations (if sending txs)

RPC URL Selection

To interact with different EVM networks, you need reliable RPC endpoints. Use ChainList's API at https://chainlist.org/rpcs.json to get a comprehensive JSON list of RPC URLs for all supported chains.

How to Select RPC URLs:

Fetch the RPC data:

bash

curl -s https://chainlist.org/rpcs.json | jq '.[] | select(.chainId == 1)'  # For Ethereum (chain ID 1)

Look for RPC URLs that are:
- Public and free: No API keys required
- No or limited tracking: Avoid URLs with "tracking": "yes"
- Fast and reliable: Prefer URLs with low latency or high score
- Open source: Prefer community-maintained endpoints
Popular choices (extracted from ChainList):
- Ethereum (ID 1): https://ethereum-rpc.publicnode.com
- BNB Smart Chain (ID 56): https://bsc-dataseed.binance.org
- Base (ID 8453): https://mainnet.base.org
- Polygon (ID 137): https://polygon-rpc.com
For production use, consider paid RPC services like Alchemy, Infura, or QuickNode for higher reliability and rate limits.
Always verify the chain ID matches your intended network to avoid connecting to wrong chains.

Common Operations

Query Account Balance

Get ETH balance of an address:

bash

cast balance <address> --rpc-url <rpc_url>

Get ERC20 token balance:

bash

cast call <token_contract> "balanceOf(address)(uint256)" <address> --rpc-url <rpc_url>

Call Contract Functions (Read-Only)

Call a view/pure function:

bash

cast call <contract_address> "<function_signature>" [args...] --rpc-url <rpc_url>

Example - get token total supply:

bash

cast call 0xA0b86a33E6441e88C5F2712C3E9b74B6F3f5a8b8 "totalSupply()(uint256)" --rpc-url <rpc_url>

Send Transactions

Send ETH:

bash

cast send --private-key <pk> --rpc-url <rpc_url> <to_address> --value <amount_in_wei>

Call contract function (write):

bash

cast send --private-key <pk> --rpc-url <rpc_url> <contract_address> "<function_signature>" [args...]

Blockchain Inspection

Get latest block number:

bash

cast block-number --rpc-url <rpc_url>

Get block details:

bash

cast block <block_number> --rpc-url <rpc_url>

Get transaction details:

bash

cast tx <tx_hash> --rpc-url <rpc_url>

Contract Deployment

Deploy a contract:

bash

cast send --private-key <pk> --rpc-url <rpc_url> --create <bytecode> [constructor_args...]

Decoding Data

Decode hex data:

bash

cast --to-ascii <hex_string>
cast --to-dec <hex_string>

Network-Specific Examples

Ethereum Mainnet

bash

export ETH_RPC_URL=https://eth-mainnet.alchemyapi.io/v2/YOUR_API_KEY
cast balance 0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045

Polygon

bash

cast balance <address> --rpc-url https://polygon-rpc.com/

Local Development (Anvil)

bash

cast balance <address> --rpc-url http://127.0.0.1:8545

Error Handling

RPC errors: Check endpoint URL and network connectivity
Insufficient funds: Ensure account has enough ETH for gas + value
Contract errors: Verify function signatures and parameter types
Private key errors: Ensure correct format (0x prefixed hex)

Advanced Usage

Batch Operations

Use shell loops for multiple queries:

bash

for addr in addr1 addr2 addr3; do
  echo "Balance of $addr: $(cast balance $addr --rpc-url $RPC_URL)"
done

Gas Estimation

Estimate gas for a transaction:

bash

cast estimate --rpc-url <rpc_url> <to_address> --value <amount>

ABI Interactions

For complex contracts, save ABI to file and use:

bash

cast call --abi <abi_file> <contract> <function> [args...]

Security Notes

Never expose private keys in scripts or logs
Use environment variables for sensitive data
Test on testnets before mainnet operations
Verify contract addresses and function signatures
Monitor gas prices for transaction timing

evm-swiss-knife

NPX Install

Tags

SKILL.md Content

EVM Swiss Knife

Installation

Quick Install (Linux/Mac)

Prerequisites

RPC URL Selection

How to Select RPC URLs:

Common Operations

Query Account Balance

Call Contract Functions (Read-Only)

Send Transactions

Blockchain Inspection

Contract Deployment

Decoding Data

Network-Specific Examples

Ethereum Mainnet

Polygon

Local Development (Anvil)

Error Handling

Advanced Usage

Batch Operations

Gas Estimation

ABI Interactions

Security Notes