web3-blockchain

web3-blockchain is a skill for Claude Code, Codex from hoangatg/ai-agent-toolkit. It costs 29 tokens per session (864 once invoked), scanned A, original, MIT.

Blockchain development guidance for building decentralized applications, where parts of the application run on a blockchain instead of a central server. It covers smart contracts, wallets, blockchain networks, and Web3 libraries.

In plain words
What is it for?
Use it to build dApps, write and test Solidity or Rust smart contracts, connect wallets, and interact with Ethereum, Solana, Polygon, Base, or Near.
Why use it?
It helps you choose a blockchain and development tools while applying common smart-contract safety practices such as access control and protection against reentrancy.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Good fit Use it to build dApps, write and test Solidity or Rust smart contracts, connect wallets, and interact with Ethereum, Solana, Polygon, Base, or Near.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/hoangatg/ai-agent-toolkit/web3-blockchain
Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Any agent
npx skills add hoangatg/ai-agent-toolkit --skill web3-blockchain
Clone the repo
git clone --depth 1 https://github.com/hoangatg/ai-agent-toolkit

Made for: Claude Code, Codex.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for web3-blockchain

README.md
[![agentmods](https://agentmods.dev/badge/skills/hoangatg/ai-agent-toolkit/web3-blockchain/github.svg)](https://agentmods.dev/skills/hoangatg/ai-agent-toolkit/web3-blockchain)
Your own site
<a href="https://agentmods.dev/skills/hoangatg/ai-agent-toolkit/web3-blockchain"><img src="https://agentmods.dev/badge/skills/hoangatg/ai-agent-toolkit/web3-blockchain/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for web3-blockchain

Your own site · 80×15
<a href="https://agentmods.dev/skills/hoangatg/ai-agent-toolkit/web3-blockchain"><img src="https://agentmods.dev/badge/skills/hoangatg/ai-agent-toolkit/web3-blockchain.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 29 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 864 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00029 $0.00864
Opus 5 $0.00015 $0.00432
Sonnet 5 $0.00006 $0.00173
Haiku 4.5 $0.00003 $0.00086

Measured 8d ago against content hash 43bc0f58b473, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-11, from the pricing page.

Security

Grade A, and why

web3-blockchain scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 8d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

.agent/skills/web3-blockchain/SKILL.md · 132 lines

How it starts

The opening of the file, as written. The whole thing — 132 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Web3 & Blockchain

Decentralized. Trustless. Immutable. Build applications without intermediaries.


1. Technology Stack

Blockchain Selection

Blockchain Best For Language
Ethereum DeFi, NFTs, dApps Solidity
Solana High throughput, low fees Rust
Polygon Ethereum L2, low cost Solidity
Base Coinbase L2, consumer apps Solidity
Near Developer-friendly Rust/JS

Development Tools

Tool Purpose
Hardhat Ethereum dev environment
Foundry Fast, Solidity-native testing
Remix IDE Browser-based Solidity IDE
Anchor Solana framework
ethers.js / viem JS blockchain interaction
wagmi React hooks for Ethereum

2. Smart Contract Principles

Solidity Best Practices

Principle Application
Checks-Effects-Interactions Validate → update state → external calls
Minimal storage Storage is expensive ($$$)
Reentrancy guard Use OpenZeppelin ReentrancyGuard
Access control Ownable, roles-based
Events Emit for all state changes
Upgradability Proxy pattern (with caution)

3. dApp Architecture

Frontend Integration

User → Wallet (MetaMask) → dApp Frontend → Smart Contract → Blockchain
                               ↓
                          Backend (indexer, APIs)
Layer Technology
Frontend React + wagmi + viem
Wallet MetaMask, WalletConnect, Coinbase Wallet
Indexing The Graph, custom indexer
Storage IPFS, Arweave (off-chain data)
Backend Node.js for off-chain logic

4. Security

Common Vulnerabilities

Vulnerability Prevention
Reentrancy Checks-Effects-Interactions, ReentrancyGuard
Integer overflow Solidity 0.8+ (built-in checks)
Front-running Commit-reveal schemes
Access control Role-based, multi-sig
Oracle manipulation Use Chainlink, multiple sources

Read the full file on GitHub · 132 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 8d ago First seen · 132 lines · 29 tokens per session scan A 43bc0f58b473

Subscribe to this mod's changes

web3-blockchain is a skill published in the GitHub repository hoangatg/ai-agent-toolkit (1 stars, last pushed 5mo ago), licensed MIT. It adds 29 tokens to every session and 864 once invoked, about $0.0001 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-03.