evm-swiss-knife

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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)

1. Install Foundryup:
   ```bash
   curl -L https://foundry.paradigm.xyz | bash
   ```

2. Source your shell configuration or start a new terminal:
   ```bash
   source ~/.bashrc  # or ~/.zshrc
   ```

3. Install Foundry:
   ```bash
   foundryup
   ```

4. 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:

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

2. 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

3. 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

4. For production use, consider paid RPC services like Alchemy, Infura, or QuickNode for higher reliability and rate limits.

5. 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

From kukapay/crypto-skills, MIT.

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