Top 4 Claude Skills for Smart Contract and Blockchain Developers

If you spend time on r/ethdev or the Ethereum Stack Exchange, you have probably noticed the conversation around AI-assisted development shifting from skeptical to pragmatic. Smart contract developers are no longer asking whether to use AI. They are asking how to use it without introducing new vulnerabilities.

The data backs this up. Smart-contract developers and auditors indicate that AI use in programming will make crypto safer despite earlier reports suggesting AI-generated code might introduce security risks. Nearly every developer in the community uses some AI tools, with most relying on ChatGPT and Cursor. Developers emphasize that AI use is "fine" for smart contract development, specifically because "smart contract development requires so much testing and refinement" that bugs are corrected before deployment. The key insight: AI can increase code quality "only in pair with a human who understands the coding."

This is not about delegating to AI. It is about AI handling the parts of smart contract development that were always tedious but necessary: checking for known vulnerability patterns, generating test cases for edge conditions, scanning across multiple blockchain platforms, and translating security best practices into actual code. The developer provides judgment, domain expertise, and security awareness. Claude handles the grunt work.

Claude Skills fit this workflow perfectly. They are not magic security solutions. They are structured, repeatable knowledge bases that formalize the security checks, audit workflows, and platform-specific vulnerability patterns that experienced blockchain developers already know but might miss on a Friday afternoon when shipping a DeFi protocol before the weekend.

What are Claude Skills (and what are they not)?

The Claude ecosystem has several extension mechanisms, and they are easy to confuse. Here is a quick disambiguation:

• CLAUDE.md files are persistent project memory. They load into every session and tell Claude things like "this project uses Hardhat" or "always check for reentrancy." They are always-on context, not on-demand capabilities.

• Custom Slash Commands (.claude/commands/*.md) were simple prompt templates triggered by /command-name. They have been effectively merged into Skills. Skills that define an argument-hint in their frontmatter can be invoked as slash commands, while others activate contextually based on your task.

• MCP Servers are running processes that expose tools and data sources via the Model Context Protocol. They let Claude call APIs, query databases, or interact with external services. They require a server process and code.

• Claude Connectors connect Claude to external services such as Slack, Figma, or Asana via remote MCP servers using OAuth.

• Claude Apps refers to the platforms where Claude runs (Claude.ai, Claude Code, mobile, desktop), not extensions to Claude.

• Plugins are bundles that package skills, agents, hooks, and MCP servers together for distribution.

Claude Skills are directories containing a SKILL.md file (with YAML frontmatter and markdown instructions) plus optional supporting files like scripts, templates, and reference docs. What makes them unique:

1. They are directories, not single files. A skill can bundle shell scripts, Python helpers, reference documentation, and asset files alongside its instructions.

2. Progressive disclosure. At startup, Claude loads only each skill's name and description from the YAML frontmatter (roughly 100 tokens per skill), similar to how MCP tool descriptions are injected into context. Claude matches your task against those descriptions to decide which skill to activate. When it finds a match, it loads the full SKILL.md instructions. Supporting files (references, scripts, assets) load only when explicitly needed during execution. This three-tier approach keeps your context window lean even with dozens of skills installed. It also means a skill's description field is critical: vague descriptions activate unreliably, while precise descriptions with explicit trigger phrases (like "Use when auditing Solana/Anchor programs") activate consistently.

3. They can execute code. Skills can include scripts in scripts/ that Claude runs during execution, and they can use the !command`` syntax to inject dynamic output into the prompt context.

4. They follow an open standard. The Agent Skills specification has been adopted by Claude Code, OpenAI Codex, Cursor, Gemini CLI, and others, making skills portable.

5. They can register as slash commands. Skills that include an argument-hint field in their YAML frontmatter can be invoked directly as /skill-name. For example, a skill installed at .claude/skills/solana-scan/ with an argument hint becomes available as /solana-scan. Skills without an argument hint activate contextually instead, meaning Claude picks them up automatically when your task matches their description.

The official specification and Anthropic's skills documentation cover the full format. The Anthropic engineering blog post on Agent Skills is also worth reading for the design rationale.

Installing a Claude Skill

Installing a skill takes about 30 seconds.

Project level (shared with your team via version control):

1your-project/
2└── .claude/
3    └── skills/
4        └── skill-name/
5            ├── SKILL.md
6            └── resources/
7                └── vulnerability-patterns.md

User level (personal, available across all projects):

1~/.claude/
2└── skills/
3    └── skill-name/
4        ├── SKILL.md
5        └── resources/
6            └── REFERENCE.md

Via plugins (for skill collections like Trail of Bits):

1/plugin marketplace add trailofbits/skills
2/plugin menu

Skills at the project level are shared with teammates through source control. User-level skills are private to you. When names conflict, enterprise skills take precedence over personal skills, which take precedence over project skills.

One important caveat: the Agent Skills ecosystem is new and growing fast, which means supply chain security matters. Snyk's ToxicSkills research found prompt injection in 36% of skills tested and 1,467 malicious payloads across the ecosystem. Always review a skill's SKILL.md and any bundled scripts before installing. Treat skills the way you would treat any third-party code you run in your environment.

Building a Claude Skill? If you are creating or maintaining an open source Claude Skill or MCP server for smart contract development, blockchain infrastructure, or Web3 tooling, the Snyk Secure Developer Program provides free enterprise-level security scanning for open source projects. Snyk secures 585,000+ open source projects and offers full enterprise access, Discord community support, and integration assistance to qualifying maintainers. Apply here if you have an existing project, or here if you are starting a new one.

The reality of Claude Skills for blockchain development

Before diving into the list, there is something you should know: the Claude Skills ecosystem for blockchain development is sparse compared to general cybersecurity tooling. Trail of Bits' Building Secure Contracts plugin (11 skills covering Algorand, Cairo, Cosmos, Solana, Substrate, and TON) represents the majority of production-grade smart contract security skills available today. Beyond that, you will find a handful of experimental projects and emerging skills for specific use cases, such as on-chain analytics.

This is not a "Top 10" list padded with marginal tools. This is an honest assessment of what exists and works. If you are looking for Skills covering Hardhat workflows, Foundry integration, or gas optimization patterns, those do not exist yet as standalone skills (though you can build your own using the Agent Skills specification). What does exist is focused squarely on security auditing across multiple blockchain platforms.

The good news: the skills that do exist are comprehensive, actively maintained by security experts, and cover the vulnerability patterns that actually matter in production smart contract development.

Now, onto the list.

1. Trail of Bits building secure contracts

Source: trailofbits/skills (plugin: building-secure-contracts). Stars: 2,482. Author: Omar Inuwa. License: Creative Commons Attribution-ShareAlike 4.0. Last updated: January 2026. Verified SKILL.md: Yes (11 skill directories, each with SKILL.md).

Smart contract security is a specialized domain where the cost of a missed vulnerability is often measured in millions of dollars. This plugin packages 11 skills based on Trail of Bits' open source Building Secure Contracts framework and Not So Smart Contracts vulnerability repository.

6 Vulnerability scanners for platform-specific attack patterns:

5 Development guidelines assistants:

• /audit-prep-assistant for preparing codebases for security reviews (1-2 weeks before an audit)

• /code-maturity-assessor using Trail of Bits' 9-category maturity framework

• /guidelines-advisor for architecture, upgradeability, and implementation review

• /secure-workflow-guide providing a 5-step validation process (Slither, special features, visual inspection, property testing, manual review)

• /token-integration-analyzer for ERC20/ERC721 conformity and 20+ weird token patterns

These skills integrate with security tools when available (Slither, Echidna, Manticore, Tealer) and gracefully fall back to manual analysis when they are not.

What makes this different

Unlike generic "audit this contract" prompts, these skills encode platform-specific vulnerability knowledge. The Solana scanner knows to check for arbitrary CPI (cross-program invocation), improper PDA (program-derived address) validation, missing signer checks, missing ownership checks, sysvar spoofing, and account confusion. The Cairo scanner checks for felt overflow, reentrancy, missing authorization, unchecked delegate calls, uninitialized storage, and missing event emissions.

This is the kind of knowledge that takes years of blockchain security work to accumulate. Having it formalized in a skill means Claude checks for these patterns automatically rather than requiring you to remember every platform-specific footgun.

Installation

1/plugin marketplace add trailofbits/skills
2# Select building-secure-contracts from the plugin menu
3/plugin menu

Or manually:

1git clone https://github.com/trailofbits/skills.git ~/trail-of-bits-skills
2ln -s ~/trail-of-bits-skills/plugins/building-secure-contracts/skills/* ~/.claude/skills/

Usage

1Scan this Solana program for vulnerabilities
2Prepare this codebase for a security audit
3Assess the maturity of this smart contract project
4Analyze this ERC20 token for weird behaviors
5Review this Substrate pallet for security issues

Who this is for: Smart contract developers on Solana, Algorand, Cairo/StarkNet, Cosmos, Substrate/Polkadot, or TON. DeFi protocol teams are preparing for audits. Blockchain security auditors who want structured vulnerability checklists.

Related Snyk resources:

• NPM security: preventing supply chain attacks

• Detect and prevent dependency confusion attacks on npm

• Snyk Vulnerability Database

2. SecSkills Web3 Pentesting

Source: trilwu/secskills (skill: web3-blockchain). Stars: 5. License: MIT. Last updated: November 2025. Verified SKILL.md: Yes.

While Trail of Bits focuses on secure development practices, the SecSkills Web3 pentesting skill takes the offensive security approach. At nearly 12,000 characters, this skill is a comprehensive guide to smart contract exploitation, DeFi attack vectors, and Web3 application security testing.

What it covers

Smart contract vulnerabilities:

• Reentrancy attacks (with exploit code).

• Integer overflow/underflow.

• Access control bypasses.

• Unchecked external calls.

• Delegatecall injection.

• Front-running and MEV exploitation.

• Price oracle manipulation.

• Denial of service patterns.

DeFi-specific attacks:

• Flash loan exploits.

• Impermanent loss exploitation.

• Governance attacks.

• Liquidity pool manipulation.

Development and testing tools:

• Hardhat and Foundry test framework examples.

• Slither, Mythril, Echidna, and Manticore integration.

• Mainnet forking for exploit development.

• Transaction simulation patterns.

Web3 frontend security:

• Wallet connection vulnerabilities.

• Signature replay attacks.

• Transaction simulation for safety checks.

NFT security:

• Metadata manipulation.

• Minting exploits.

• Royalty bypass techniques.

The skill includes ready-to-use exploit code, tool commands, and best practices for responsible security testing.

Installation

1/plugin marketplace add trilwu/secskills
2/plugin install trilwu/secskills

Or manually:

1git clone https://github.com/trilwu/secskills.git
2cp -r secskills/secskills/skills/web3-blockchain ~/.claude/skills/

Usage

SecSkills activates contextually when you describe smart contract security testing scenarios:

1Test this DeFi protocol for reentrancy vulnerabilities
2I found a flash loan opportunity. Help me write an exploit
3Analyze this NFT minting contract for security issues
4Set up a Hardhat fork to test this exploit on mainnet

Who this is for: Smart contract auditors, bug bounty hunters, security researchers working in Web3, developers who want to understand attack patterns to write more secure contracts.

Important: This skill is designed for authorized security testing, bug bounty programs, CTF competitions, and educational purposes. Always operate within your scope of engagement.

Related Snyk resources:

• Preventing malicious packages and supply chain attacks with Snyk

• SHA1-Hulud npm supply chain incident

• Why npm lockfiles can be a security blindspot

3. Arkham Intelligence API

Source: Vyntral/arkham-intelligence-claude-skill. Stars: 2. License: Not specified. Last updated: February 2026. Verified SKILL.md: Yes.

Blockchain development is not just about writing secure smart contracts. It is also about understanding what happens on-chain after deployment. The Arkham Intelligence skill integrates Arkham's blockchain intelligence API to give Claude access to wallet analytics, whale tracking, token flows, and on-chain investigations across 10+ blockchains.

What it provides

At 16,000+ characters, this is one of the most comprehensive API integration skills available. It includes:

Intelligence and Entity Analysis:

• Address and entity lookup (Wintermute, Jump Trading, Binance, etc.).

• Wallet balance tracking across multiple chains.

• Portfolio analysis with automatic USD valuation.

• Entity type classification (CEX, market maker, fund, individual, protocol).

Transfer and Flow Tracking:

• Whale movement monitoring (configurable USD thresholds).

• Token accumulation analysis (who's buying/selling).

• Large transfer alerts.

• Cross-chain transaction history.

Token Analytics:

• Top holder identification (grouped by entity).

• Trending tokens discovery.

• Volume and flow analysis.

• Market maker position tracking.

Network Analysis:

• Entity counterparty mapping (who trades with whom).

• DeFi position tracking (Aave, Compound, etc.).

• CEX flow analysis for market sentiment.

Use cases (with working examples):

1# Track smart money positions
2# Find what market makers are accumulating
3# Monitor hacker/exploit fund movements
4# Compare institutional portfolios
5# Analyze CEX inflows/outflows for sentiment
6# Discover token holder concentrations
7# Track governance token accumulation

The skill includes extensive jq filtering patterns to handle Arkham's complex, chain-organized response structures, plus workarounds for API quirks and rate limiting strategies.

Prerequisites

Requires an Arkham API key configured in Claude Code settings:

1// ~/.claude/settings.json
2{
3  "env": {
4    "ARKHAM_API_KEY": "your_api_key_here"
5  }
6}

Installation

1git clone https://github.com/Vyntral/arkham-intelligence-claude-skill.git
2cp -r arkham-intelligence-claude-skill/.claude/skills/arkham-api ~/.claude/skills/

Usage

1Who are the top 10 holders of this token?
2Show me large ETH transfers from market makers in the last 24 hours
3What tokens is Wintermute accumulating this week?
4Track the recent movements of funds from the XYZ exploit
5Analyze CEX flows to gauge market sentiment for SOL

Who this is for: DeFi developers monitoring protocol health, traders tracking whale movements, security researchers investigating exploits, token teams analyzing holder distribution.

Related Snyk resources:

• G_Wagon Infostealer: Fake npm UI Library Steals Crypto Wallets

• npm Supply Chain Attack via Open Source maintainer compromise

4. Awesome Sui Claude Skills

Source: 0xBondSUI/awesome-sui-claude-skills. Stars: 0. License: Not specified. Last updated: January 2026. Status: Early stage / placeholder repository.

This repository represents the emerging ecosystem of Sui blockchain development skills. While currently a placeholder (README-only repository with no SKILL.md files), it signals developer interest in Sui-specific Claude Skills for Move smart contracts, DeFi protocols, and ecosystem tooling.

Why this matters

Sui's Move language has different security properties than Solidity (no reentrancy, resource-oriented programming, object-centric storage), which means Ethereum-focused skills do not translate directly. As the Sui ecosystem grows, dedicated skills for Move development patterns, Sui-specific security checks, and object model best practices will become valuable.

Current state

The repository is a curated collection concept without implementation. If you are building on Sui and want to create skills, this could be a starting point for collaboration.

Related Snyk resources:

• Snyk Advisor for package health

• The mysterious supply chain concern of string-width-cjs npm package

A note on security when using security skills

There is an irony in using AI skills to improve your security posture while the skills ecosystem itself has security risks. Snyk's ToxicSkills study found that 13% of skills tested contained critical security flaws, and some actively attempted to exfiltrate credentials. The SKILL.md to Shell Access research demonstrated how three lines of markdown in a skill file can grant an attacker shell access to your machine.

Before installing any skill:

1. Read the SKILL.md and any bundled scripts. Skills are markdown and shell scripts, not compiled binaries. You can read every line.

2. Check the source. Skills from established security firms (Trail of Bits) carry lower risk than anonymous GitHub repositories.

3. Review permissions. The allowed-tools frontmatter field shows what tools a skill can use. A skill that needs Bash access warrants more scrutiny than one that only uses Read and Grep.

4. Use Snyk to scan. If you are already using Snyk Code, you can scan skill scripts the same way you scan any code.

The skills on this list are from reputable sources with clear licensing. But the general principle applies: trust, then verify.

Wrapping up

The Claude Skills ecosystem for blockchain development is smaller and more focused than general-purpose cybersecurity tooling. What exists is concentrated on what matters most: security auditing across multiple blockchain platforms, offensive security testing for smart contracts, and on-chain intelligence gathering.

Trail of Bits' Building Secure Contracts plugin alone covers six blockchain platforms with vulnerability scanners encoding years of security research. SecSkills brings offensive security knowledge for Web3 pentesting. Arkham Intelligence adds real-time blockchain analytics. These are not toys. They are production-grade tools that formalize expert knowledge into repeatable workflows.

The gap in the ecosystem is notable: there are no mature skills yet for Hardhat workflows, Foundry test generation, gas optimization, or ERC token standard scaffolding. If you work on those problems regularly, building your own skill using the Agent Skills specification would benefit both your workflow and the broader community.

If you are already using Claude Code for blockchain development, installing the Trail of Bits plugin is a 5-minute investment that pays off the first time Claude catches a platform-specific vulnerability pattern you would have missed. Add SecSkills if you are doing security testing. Add Arkham if you need on-chain intelligence. That is the entire current landscape.

As the ecosystem matures, expect to see more skills covering Layer 2 development, zero-knowledge proof systems, and blockchain-specific testing frameworks. For now, what exists is focused on getting the security fundamentals right.

If you are looking for MCP servers instead of Claude Skills for blockchain development, check if a dedicated Snyk article exists covering blockchain MCP servers (similar to 10 MCP Servers for Cybersecurity Professionals and Elite Hackers).