Agent skill

Cast Commands

A skill your agent uses when interacting with Ethereum contracts and data from the command line using Foundry's cast.

MITAuto-check passed

Install Cast Commands

skills CLI

$ npx skills add ccashwell/evm-cortex --skill cast-commands -a claude-code

Project install by default; add -g for ~/.claude/skills/.

GitHub CLI

$ gh skill install ccashwell/evm-cortex cast-commands --agent claude-code

Project scope by default; add --scope user for a personal install. Needs GitHub CLI 2.90.0 or later (public preview).

Manual copy

$ git clone --depth 1 https://github.com/ccashwell/evm-cortex.git skills-src && mkdir -p .claude/skills && cp -r skills-src/skills/cast-commands .claude/skills/cast-commands && rm -rf skills-src

Use ~/.claude/skills/ instead of .claude/skills for a personal install. The folder must contain SKILL.md.

Claude Code skills documentation · loads skills from .claude/skills/

Paste into Claude Code

Install the "cast-commands" agent skill from https://github.com/ccashwell/evm-cortex/tree/main/skills/cast-commands into .claude/skills/cast-commands/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "cast-commands", then confirm the skill loads.

Claude Code copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

$skill-installer

$skill-installer install https://github.com/ccashwell/evm-cortex/tree/main/skills/cast-commands

Type this inside Codex. $skill-installer <name> installs a curated skill from openai/skills. The installer writes to $CODEX_HOME/skills (default ~/.codex/skills). Restart Codex if the skill does not show up.

skills CLI

$ npx skills add ccashwell/evm-cortex --skill cast-commands -a codex

Project install goes to .agents/skills/; add -g for ~/.codex/skills/.

GitHub CLI

$ gh skill install ccashwell/evm-cortex cast-commands --agent codex

Project scope by default (.agents/skills/); add --scope user for a personal install.

Manual copy

$ git clone --depth 1 https://github.com/ccashwell/evm-cortex.git skills-src && mkdir -p .agents/skills && cp -r skills-src/skills/cast-commands .agents/skills/cast-commands && rm -rf skills-src

Use ~/.agents/skills/ instead of .agents/skills for a personal install.

Codex skills documentation · loads skills from .agents/skills/

Paste into Codex

Install the "cast-commands" agent skill from https://github.com/ccashwell/evm-cortex/tree/main/skills/cast-commands into .agents/skills/cast-commands/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "cast-commands", then confirm the skill loads.

Codex copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

skills CLI

$ npx skills add ccashwell/evm-cortex --skill cast-commands -a cursor

Project install goes to .agents/skills/; add -g for ~/.cursor/skills/.

GitHub CLI

$ gh skill install ccashwell/evm-cortex cast-commands --agent cursor

Project scope by default (.agents/skills/); add --scope user for a personal install.

Manual copy

$ git clone --depth 1 https://github.com/ccashwell/evm-cortex.git skills-src && mkdir -p .cursor/skills && cp -r skills-src/skills/cast-commands .cursor/skills/cast-commands && rm -rf skills-src

Use ~/.cursor/skills/ instead of .cursor/skills for a personal install.

Cursor skills documentation · loads skills from .cursor/skills/, .agents/skills/, .claude/skills/, .codex/skills/

Paste into Cursor

Install the "cast-commands" agent skill from https://github.com/ccashwell/evm-cortex/tree/main/skills/cast-commands into .cursor/skills/cast-commands/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "cast-commands", then confirm the skill loads.

Cursor copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

gemini skills install

$ gemini skills install https://github.com/ccashwell/evm-cortex.git --path skills/cast-commands

--scope user (default) or --scope workspace; --path is the subfolder of the repo that holds the skill; --consent skips the security confirmation prompt.

skills CLI

$ npx skills add ccashwell/evm-cortex --skill cast-commands -a gemini-cli

Project install goes to .agents/skills/; add -g for ~/.gemini/skills/.

GitHub CLI

$ gh skill install ccashwell/evm-cortex cast-commands --agent gemini-cli

Project scope by default (.agents/skills/); add --scope user for a personal install.

Manual copy

$ git clone --depth 1 https://github.com/ccashwell/evm-cortex.git skills-src && mkdir -p .gemini/skills && cp -r skills-src/skills/cast-commands .gemini/skills/cast-commands && rm -rf skills-src

Use ~/.gemini/skills/ instead of .gemini/skills for a personal install, then run /skills reload.

Gemini CLI skills documentation · loads skills from .gemini/skills/, .agents/skills/

Paste into Gemini CLI

Install the "cast-commands" agent skill from https://github.com/ccashwell/evm-cortex/tree/main/skills/cast-commands into .gemini/skills/cast-commands/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "cast-commands", then confirm the skill loads.

Gemini CLI copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

GitHub CLI

$ gh skill install ccashwell/evm-cortex cast-commands

Installs for Copilot at project scope by default; add --scope user for a personal install. Preview a skill first with gh skill preview. Needs GitHub CLI 2.90.0 or later (public preview).

skills CLI

$ npx skills add ccashwell/evm-cortex --skill cast-commands -a github-copilot

Project install goes to .agents/skills/; add -g for ~/.copilot/skills/.

Manual copy

$ git clone --depth 1 https://github.com/ccashwell/evm-cortex.git skills-src && mkdir -p .github/skills && cp -r skills-src/skills/cast-commands .github/skills/cast-commands && rm -rf skills-src

Use ~/.copilot/skills/ instead of .github/skills for a personal install. Commit .github/skills so cloud agent and code review can use it.

GitHub Copilot skills documentation · loads skills from .github/skills/, .claude/skills/, .agents/skills/

Paste into GitHub Copilot

Install the "cast-commands" agent skill from https://github.com/ccashwell/evm-cortex/tree/main/skills/cast-commands into .github/skills/cast-commands/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "cast-commands", then confirm the skill loads.

GitHub Copilot copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

skills CLI

$ npx skills add ccashwell/evm-cortex --skill cast-commands -a opencode

OpenCode documents no install command of its own. Project install goes to .agents/skills/; add -g for ~/.config/opencode/skills/.

GitHub CLI

$ gh skill install ccashwell/evm-cortex cast-commands --agent opencode

Project scope by default (.agents/skills/); add --scope user for a personal install.

Manual copy

$ git clone --depth 1 https://github.com/ccashwell/evm-cortex.git skills-src && mkdir -p .opencode/skills && cp -r skills-src/skills/cast-commands .opencode/skills/cast-commands && rm -rf skills-src

Use ~/.config/opencode/skills/ instead of .opencode/skills for a personal install.

OpenCode skills documentation · loads skills from .opencode/skills/, .claude/skills/, .agents/skills/

Paste into OpenCode

Install the "cast-commands" agent skill from https://github.com/ccashwell/evm-cortex/tree/main/skills/cast-commands into .opencode/skills/cast-commands/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "cast-commands", then confirm the skill loads.

OpenCode copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

Facts

Skill name: cast-commands
GitHub stars: 131
Token cost: ~1.5k tokens
SKILL.md length: 96 words
Files: 1
Skills in repo: 89
Repo updated: Sep 30, 2026
First seen: Oct 7, 2026
Licence: MIT

At a glance

A skill your agent uses when interacting with Ethereum contracts and data from the command line using Foundry's cast.

Interacting with Ethereum contracts and data from the command line using Foundrys cast
SKILL.md covers Overview, Reading State (cast call), Writing State (cast send) and Storage Inspection (cast…, plus 8 more sections
Needs PRIVATE_KEY and ETHERSCAN_API_KEY

What it does

Cast Commands is an agent skill from ccashwell/evm-cortex. Use when interacting with Ethereum contracts and data from the command line using Foundry's cast. Covers read/write calls, storage inspection, ABI encoding/decoding, block queries, and common one-liners.

Its SKILL.md is about 1.5k tokens, which your agent loads only when the skill is triggered. It is a single SKILL.md file with no bundled scripts.

It works with Ethereum. The repository describes itself as: Ethereum protocol engineering squad for AI coding assistants. The licence is MIT.

When your agent uses it

Interacting with Ethereum contracts and data from the command line using Foundrys cast

Example prompts

“/cast-commands”

Requirements

A credential in PRIVATE_KEY
A credential in ETHERSCAN_API_KEY

What it can do on your machine

Read from SKILL.md and the folder at commit f8f3301. It shows what the files ask for, not the result of running them.

Tool permissions
Pre-approves nothing: there is no allowed-tools line, so your agent's usual permission prompts apply.
From allowed-tools in the SKILL.md frontmatter.
Runs code
No scripts in the folder and no shell commands in SKILL.md (its code samples are bash).
From the folder's file list and the shell code blocks in SKILL.md.
Network
No URLs in SKILL.md.
From URLs in SKILL.md, links to its own repository left out.
Credentials
Names these keys or tokens, usually read from environment variables:
- PRIVATE_KEY
- ETHERSCAN_API_KEY
From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.

Context cost

Cast Commands loads about 1.5k tokens when it runs. Until then it costs about 54 tokens; SKILL.md has 96 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it: ~54
When it runs · the whole SKILL.md, loaded when a task matches: ~1.5k

Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.

Safety

Auto-check passed

The automated check found no risky patterns in SKILL.md.

Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); files beside SKILL.md are not scanned.

SKILL.md

The full file from ccashwell/evm-cortex at commit f8f3301, republished under its MIT licence (© ccashwell). 96 words, ~1,495 tokens.

Download SKILL.mdSave it as .claude/skills/cast-commands/SKILL.md (or your agent's skills folder).

name: cast-commands
description: Use when interacting with Ethereum contracts and data from the command line using Foundry's cast. Covers read/write calls, storage inspection, ABI encoding/decoding, block queries, and common one-liners.

Cast CLI Reference

Overview

cast is Foundry's command-line tool for interacting with EVM chains. Read state, send transactions, decode data, and inspect contracts without writing scripts.

Reading State (cast call)

bash

# Read a view function
cast call 0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48 \
  "balanceOf(address)(uint256)" 0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045 \
  --rpc-url $ETH_RPC_URL

# Read with named outputs
cast call 0xUniswapV3Pool "slot0()(uint160,int24,uint16,uint16,uint16,uint8,bool)" \
  --rpc-url $ETH_RPC_URL

# Call at a specific block
cast call 0xContract "totalSupply()(uint256)" --block 18000000 --rpc-url $ETH_RPC_URL

# Call to another address (simulated msg.sender)
cast call --from 0xWhale 0xContract "balanceOf(address)(uint256)" 0xWhale

Writing State (cast send)

bash

# Send a transaction
cast send 0xToken "transfer(address,uint256)" 0xRecipient 1000000 \
  --private-key $PRIVATE_KEY --rpc-url $ETH_RPC_URL

# Approve spending
cast send 0xToken "approve(address,uint256)" 0xSpender $(cast max-uint) \
  --private-key $PRIVATE_KEY --rpc-url $ETH_RPC_URL

# Send with value (ETH)
cast send 0xContract "deposit()" --value 1ether \
  --private-key $PRIVATE_KEY --rpc-url $ETH_RPC_URL

# Send with gas settings
cast send 0xContract "doStuff()" \
  --gas-limit 500000 --gas-price 30gwei \
  --private-key $PRIVATE_KEY --rpc-url $ETH_RPC_URL

Storage Inspection (cast storage)

bash

# Read raw storage slot
cast storage 0xContract 0 --rpc-url $ETH_RPC_URL

# Read specific slot (e.g., ERC-1967 implementation slot)
cast storage 0xProxy \
  0x360894a13ba1a3210667c828492db98dca3e2076cc3735a920a3ca505d382bbc \
  --rpc-url $ETH_RPC_URL

# Read mapping value: slot = keccak256(key . mappingSlot)
# For mapping at slot 2, key = 0xAddress:
cast index address 0xAddress 2
# Then read that computed slot
cast storage 0xContract $(cast index address 0xAddress 2)

ABI Encoding / Decoding

bash

# Encode function calldata
cast calldata "transfer(address,uint256)" 0xRecipient 1000000

# Decode calldata
cast 4byte-decode 0xa9059cbb000000000000000000000000...

# Encode constructor arguments
cast abi-encode "constructor(string,string,uint256)" "MyToken" "MTK" 1000000

# Decode ABI-encoded data
cast abi-decode "balanceOf(address)(uint256)" 0x00000000000000000000000000000000000000000000000000000000000f4240

# Get function selector (first 4 bytes of keccak256)
cast sig "transfer(address,uint256)"
# Output: 0xa9059cbb

# Reverse lookup selector
cast 4byte 0xa9059cbb

Block and Chain Info

bash

# Current block number
cast block-number --rpc-url $ETH_RPC_URL

# Block details
cast block latest --rpc-url $ETH_RPC_URL
cast block 18000000 --rpc-url $ETH_RPC_URL

# Base fee
cast base-fee --rpc-url $ETH_RPC_URL

# Gas price
cast gas-price --rpc-url $ETH_RPC_URL

# Chain ID
cast chain-id --rpc-url $ETH_RPC_URL

# Client version
cast client --rpc-url $ETH_RPC_URL

Contract Inspection

bash

# Get contract bytecode
cast code 0xContract --rpc-url $ETH_RPC_URL

# Get contract bytecode size
cast code 0xContract --rpc-url $ETH_RPC_URL | wc -c

# Generate interface from Etherscan
cast interface 0xContract --etherscan-api-key $ETHERSCAN_API_KEY

# Download verified source from Etherscan
cast etherscan-source 0xContract --etherscan-api-key $ETHERSCAN_API_KEY -d ./source

Account and Balance

bash

# ETH balance
cast balance 0xAddress --rpc-url $ETH_RPC_URL
cast balance 0xAddress --rpc-url $ETH_RPC_URL --ether  # human-readable

# Nonce
cast nonce 0xAddress --rpc-url $ETH_RPC_URL

# Resolve ENS
cast resolve-name vitalik.eth --rpc-url $ETH_RPC_URL
cast lookup-address 0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045 --rpc-url $ETH_RPC_URL

Transaction Inspection

bash

# Get transaction details
cast tx 0xTxHash --rpc-url $ETH_RPC_URL

# Get transaction receipt
cast receipt 0xTxHash --rpc-url $ETH_RPC_URL

# Decode transaction input
cast 4byte-decode $(cast tx 0xTxHash input --rpc-url $ETH_RPC_URL)

# Trace a transaction (requires archive node)
cast run 0xTxHash --rpc-url $ETH_RPC_URL

Conversion Utilities

bash

# Wei to ether
cast from-wei 1000000000000000000
# Output: 1.000000000000000000

# Ether to wei
cast to-wei 1.5
# Output: 1500000000000000000

# Hex to decimal
cast to-dec 0xff
# Output: 255

# Decimal to hex
cast to-hex 255
# Output: 0xff

# Keccak256 hash
cast keccak "Transfer(address,address,uint256)"

# Max uint256
cast max-uint
# Output: 115792089237316195423570985008687907853269984665640564039457584007913129639935

Common One-Liners

bash

# Check if address is a contract
cast code 0xAddress --rpc-url $ETH_RPC_URL | grep -q "^0x$" && echo "EOA" || echo "Contract"

# Get USDC balance (6 decimals)
cast call 0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48 \
  "balanceOf(address)(uint256)" 0xAddress --rpc-url $ETH_RPC_URL | \
  xargs -I{} cast from-wei {} 6

# Read ERC-1967 proxy implementation
cast storage 0xProxy \
  0x360894a13ba1a3210667c828492db98dca3e2076cc3735a920a3ca505d382bbc \
  --rpc-url $ETH_RPC_URL

# Simulate a swap (static call)
cast call 0xRouter \
  "getAmountsOut(uint256,address[])(uint256[])" \
  1000000000000000000 "[0xWETH,0xUSDC]" \
  --rpc-url $ETH_RPC_URL

# Estimate gas for a transaction
cast estimate 0xContract "doStuff(uint256)" 42 --rpc-url $ETH_RPC_URL

# Watch for new blocks
cast block-number --rpc-url $ETH_RPC_URL --watch

Tips

Set ETH_RPC_URL environment variable to avoid --rpc-url on every command
Use --json flag for machine-readable output
Pipe cast output to other cast commands for complex queries
Use cast wallet subcommands for key management
cast completions bash/zsh/fish generates shell completions

Files

Just SKILL.md in skills/cast-commands of ccashwell/evm-cortex.

Open the folder on GitHubat commit f8f3301

Compare with similar skills

Cast Commands next to the 5 skills that share the most tags, products or categories with it. Stars are the repository's; “used in” counts other GitHub owners with a copy.

Cast Commands compared with similar skills
Skill	Stars	Used in	Tokens	Auto-check	Licence	Repo updated
Cast Commands this skillccashwell/evm-cortex	131	—	~1.5k	Automated safety check: Pass	MIT	9 days ago
Wagmi Feature Developmentwevm/wagmi	6.8k	—	~3.8k	Automated safety check: Pass	MIT	8 days ago
Release Roundethereumjs/ethereumjs-monorepo	2.8k	—	~2k	Automated safety check: Pass	None	21 days ago
Update Est Fixturesethereumjs/ethereumjs-monorepo	2.8k	—	~3.3k	Automated safety check: Pass	None	21 days ago
Swapper Depositswapperfinance/swapper-toolkit	852	—	~1.8k	Automated safety check: Pass	MIT	6 mo ago
BNB Chain MCP Serverinternet-court/internet-court-skill	6.5k	1 repos	~1.7k	Automated safety check: Pass	MIT	1 mo ago

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Questions about Cast Commands

What does Cast Commands do?

A skill your agent uses when interacting with Ethereum contracts and data from the command line using Foundry's cast. Cast Commands is an agent skill from ccashwell/evm-cortex. Use when interacting with Ethereum contracts and data from the command line using Foundry's cast.

When should I use Cast Commands?

Cast Commands fits situations like: interacting with Ethereum contracts and data from the command line using Foundrys cast.

How do I install Cast Commands in Claude Code?

Run `npx skills add ccashwell/evm-cortex --skill cast-commands -a claude-code`. Or copy the skill folder (skills/cast-commands in ccashwell/evm-cortex) into .claude/skills/cast-commands in your project. Claude Code loads it when a task matches its description.

How do I install Cast Commands in Codex?

Run `npx skills add ccashwell/evm-cortex --skill cast-commands -a codex`. Or copy the skill folder (skills/cast-commands in ccashwell/evm-cortex) into .agents/skills/cast-commands in your project. Codex loads it when a task matches its description.

Can I use Cast Commands in Cursor, Gemini CLI or GitHub Copilot?

Cursor, Gemini CLI, GitHub Copilot and OpenCode also load SKILL.md folders. With the skills CLI, run `npx skills add ccashwell/evm-cortex --skill cast-commands -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/cast-commands, .gemini/skills/cast-commands, .github/skills/cast-commands and .opencode/skills/cast-commands in your project.

What does Cast Commands need to run?

Going by SKILL.md and its folder, Cast Commands needs credentials named PRIVATE_KEY and ETHERSCAN_API_KEY. Our summary lists: A credential in PRIVATE_KEY; A credential in ETHERSCAN_API_KEY.

Does Cast Commands access the network?

SKILL.md contains no URLs. Any network use would come from the scripts or tools the agent runs. This is read from the text; nothing was executed.

Is Cast Commands safe to install?

Our automated static check of SKILL.md found no risky patterns, such as piping downloads into a shell, reading credential files or hidden Unicode. It is not a guarantee. Review the folder before installing.

What licence does Cast Commands use?

Cast Commands is published under the MIT licence (the repository's licence). It allows redistribution, so the full SKILL.md is shown on this page.

How many tokens does Cast Commands use?

About 1.5k tokens (SKILL.md is roughly 6k characters). Agents keep only the skill's name and description in context until a task matches; then they load SKILL.md in full.

What are the alternatives to Cast Commands?

Skills that share tags, products or a category with Cast Commands: Wagmi Feature Development (wevm/wagmi, 6.8k stars), Release Round (ethereumjs/ethereumjs-monorepo, 2.8k stars), Update Est Fixtures (ethereumjs/ethereumjs-monorepo, 2.8k stars) and Swapper Deposit (swapperfinance/swapper-toolkit, 852 stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.

Who maintains Cast Commands?

ccashwell (a GitHub user) maintains it in ccashwell/evm-cortex, which has 131 GitHub stars. The repository holds 89 skills in this directory. The repository was last updated on September 30, 2026.

Source: ccashwell/evm-cortex on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.

Install Cast Commands

Facts

At a glance

What it does

When your agent uses it

Example prompts

Requirements

What it can do on your machine

Tool permissions

Runs code

Network

Credentials

Context cost

Safety

SKILL.md

Cast CLI Reference

Overview

Reading State (cast call)

Writing State (cast send)

Storage Inspection (cast storage)

ABI Encoding / Decoding

Block and Chain Info

Contract Inspection

Account and Balance

Transaction Inspection

Conversion Utilities

Common One-Liners

Tips

Files

Compare with similar skills

Similar skills

More from ccashwell/evm-cortex

Related

Questions about Cast Commands