What is blockchain-auditor?

A security-audit workflow for Solidity smart contracts, which are programs that run on blockchains. It looks for flaws that could let an ordinary account take funds or gain unauthorized access.

Use it to inspect verified source code or raw bytecode, check contract structure and balances, run static analysis, and test possible exploits on forked networks.

It helps find exploitable weaknesses even when a contract's source code is unavailable, and lets findings be tested against a blockchain fork.

blockchain-auditor — Skill for Claude Code by ckorhonen

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 ckorhonen/claude-skills --skill blockchain-auditor

Clone the repo

git clone --depth 1 https://github.com/ckorhonen/claude-skills

Made for: Claude Code.

Or install claude-skills, the plugin that ships this one along with the rest of its 62 skills, 4 commands, 7 agents.

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.

README.md

[![agentmods](https://agentmods.dev/badge/skills/ckorhonen/claude-skills/blockchain-auditor/github.svg)](https://agentmods.dev/skills/ckorhonen/claude-skills/blockchain-auditor)

Your own site

<a href="https://agentmods.dev/skills/ckorhonen/claude-skills/blockchain-auditor"><img src="https://agentmods.dev/badge/skills/ckorhonen/claude-skills/blockchain-auditor/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.

Your own site · 80×15

<a href="https://agentmods.dev/skills/ckorhonen/claude-skills/blockchain-auditor"><img src="https://agentmods.dev/badge/skills/ckorhonen/claude-skills/blockchain-auditor.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 80 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 4,151 The whole file, excluding the scripts and references it only reads on demand.

Security scan B 3 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.

Model	Per session	Once invoked
Fable 5.1	$0.00080	$0.04151
Opus 5	$0.00040	$0.02076
Sonnet 5	$0.00016	$0.00830
Haiku 4.5	$0.00008	$0.00415

Measured 11d ago against content hash aed407756552, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-11, from the pricing page.

Security

Grade B, and why

blockchain-auditor scanned grade B with 3 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 11d 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.

Downloads and executes remote codemediumSupply chain

curl | sh runs whatever the server returns today, which is not necessarily what it returned when this was reviewed.

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

Downgraded: this mod is about security review, or the phrase is quoted, so it is likely naming the pattern rather than instructing it.

Unrestricted tool accesslowExcessive agency

A wildcard tool grant or "run any command" leaves no least-privilege boundary at all.

- `delegatecall` - can execute arbitrary code

Downgraded: this mod is about security review, or the phrase is quoted, so it is likely naming the pattern rather than instructing it.

Makes network callslowCapability

Not a fault in itself. Listed so you know the mod talks to something, and to what.

curl "https://api.etherscan.io/api?module=contract&action=getsourcecode&address=<address>&apikey=$ETHERSCAN_API_KEY"

skills/blockchain-auditor/SKILL.md · 481 lines

How it starts

The opening of the file, as written. The whole thing — 481 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Blockchain Security Auditor

Systematically audit smart contracts to identify exploitable vulnerabilities that allow an unprivileged account to extract funds or gain unauthorized access.

Quick Start

# For verified contracts (Etherscan source available)
cast etherscan-source <address> --chain mainnet

# For unverified contracts (bytecode only)
cast code <address> --rpc-url $ETH_RPC_URL
cast disassemble <bytecode>

# Fork testing
forge test --fork-url $ETH_RPC_URL -vvv

# Static analysis
slither . --checklist

Audit Methodology

Phase 1: Reconnaissance

Gather contract information:

# Check balance
cast balance <address> --rpc-url $ETH_RPC_URL

# Get bytecode
cast code <address> --rpc-url $ETH_RPC_URL

# Check if verified on Etherscan
curl "https://api.etherscan.io/api?module=contract&action=getsourcecode&address=<address>&apikey=$ETHERSCAN_API_KEY"

# Check for proxy implementation
cast storage <address> 0x360894a13ba1a3210667c828492db98dca3e2076cc3735a920a3ca505d382bbc --rpc-url $ETH_RPC_URL

Identify contract type:
- Multi-sig wallet (addOwner, execute, confirmTransaction)
- Token contract (transfer, approve, balanceOf)
- DeFi protocol (deposit, withdraw, swap, liquidate)
- Lending/borrowing (Compound/Aave-style)
- AMM/DEX (Uniswap v2/v3-style with liquidity pools)
- Proxy pattern (EIP-1967, UUPS, Transparent, Beacon)
- Vault/yield aggregator (ERC-4626)
- Cross-chain bridge (lock/mint, burn/release)
- NFT contract (ERC-721, ERC-1155)

Phase 2: Source Code Analysis (Verified Contracts)

Identify high-risk functions:
- selfdestruct / suicide - can drain all ETH
- delegatecall - can execute arbitrary code
- call with user-controlled data - arbitrary calls
- transfer / send without checks - reentrancy
- withdraw / claim / redeem - fund extraction points
- initialize / init - proxy initialization (can it be called twice?)
- permit / permitAll - off-chain approval bypass
- flash / flashLoan - flash loan entry points

Read the full file on GitHub · 481 lines

Files

What ships with it

1 file beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

reference.md 8.0 KB

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.

11d ago First seen · 481 lines · 80 tokens per session scan B aed407756552

Subscribe to this mod's changes

blockchain-auditor is a skill published in the GitHub repository ckorhonen/claude-skills (14 stars, last pushed 2mo ago), licensed MIT. It adds 80 tokens to every session and 4,151 once invoked, about $0.0004 per session on Opus 5. A static security scan graded it B with 3 findings (downloads and executes remote code, unrestricted tool access, makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

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blockchain-auditor