echidna

Fuzz Ethereum smart contracts to falsify invariants and trigger assertion failures.

4|1|Updated Jan 30, 2026

Search Tags:#security #auditing #smart contracts #property-based testing #fuzzing #echidna

Ready to run

npx skills add https://github.com/hairyf/blockchain-skills --skill echidna

💬 Prompt for ChatGPT / Claude Chat▼

Please help me install this Agent Skill.
Skill: echidna
Source: https://github.com/hairyf/blockchain-skills/tree/main/skills/echidna
Command: npx skills add https://github.com/hairyf/blockchain-skills --skill echidna

SYSTEM DOCUMENTATION & REQUIREMENTS

💡 This Skill includes references (resource) components.

What problem does it solve?

This Skill helps developers find vulnerabilities in Ethereum smart contracts by automatically generating random test cases to uncover bugs and ensure contract integrity.

Core Features & Use Cases

Property-Based Fuzzing: Falsify user-defined invariants (functions returning bool) by generating random call sequences.
Assertion Testing: Discover inputs that trigger Solidity assert(...) failures.
Use Case: A smart contract developer can use Echidna to automatically test a new DeFi protocol's core logic, ensuring that critical invariants like "total supply never exceeds max supply" or "user balances are always non-negative" hold true under various conditions.

Quick Start

Use the echidna skill to fuzz the contract located at 'contracts/MyToken.sol' with the configuration file 'config/fuzz.yaml'.

Frequently Asked Questions about echidna

High-intent search queries and answers about installing and using this skill.

FAQPage Schema

How do I fuzz Ethereum smart contracts to find security vulnerabilities?▼

You can fuzz Ethereum smart contracts by generating random call sequences to falsify user-defined invariants or trigger assertion failures, automatically uncovering security vulnerabilities and ensuring contract integrity.

What is property-based fuzzing for Solidity smart contracts?▼

Property-based fuzzing for Solidity smart contracts is an automated testing technique that generates random call sequences to falsify user-defined boolean invariants, ensuring core protocol logic holds true under various unpredictable conditions.

Does Echidna fuzzing work with Foundry and Hardhat build systems?▼

Yes, Echidna fuzzing supports direct integration with popular build systems like Foundry and Hardhat, allowing developers to seamlessly incorporate property-based testing into existing smart contract workflows.

Can I use assertion testing to discover inputs that break smart contract logic?▼

Yes, you can use assertion testing to automatically discover specific random inputs that trigger Solidity assert failures, helping identify edge cases that break smart contract logic before deployment.

What is the difference between property-based fuzzing and symbolic execution for smart contract auditing?▼

Property-based fuzzing generates random call sequences to test invariants, while symbolic execution calculates exact input paths to falsify logic. Echidna primarily uses fuzzing but offers symbolic execution as an advanced feature for deeper coverage analysis.

Why does my smart contract fuzzer struggle to find deep vulnerabilities?▼

Fuzzers may struggle with deep vulnerabilities due to limited coverage. Echidna addresses this by offering advanced features like symbolic execution and coverage analysis to guide random call sequences toward untested code paths.