Agent skill

Foundry Fuzz Mirrors

Create Foundry fuzz tests from deterministic unit tests. An agent skill from aviggiano/security.

MITAuto-check passedTesting & QA

Install Foundry Fuzz Mirrors

skills CLI

$ npx skills add aviggiano/security --skill foundry-fuzz-mirrors -a claude-code

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

GitHub CLI

$ gh skill install aviggiano/security foundry-fuzz-mirrors --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/aviggiano/security.git skills-src && mkdir -p .claude/skills && cp -r skills-src/skills/foundry-fuzz-mirrors .claude/skills/foundry-fuzz-mirrors && 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 "foundry-fuzz-mirrors" agent skill from https://github.com/aviggiano/security/tree/main/skills/foundry-fuzz-mirrors into .claude/skills/foundry-fuzz-mirrors/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "foundry-fuzz-mirrors", 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/aviggiano/security/tree/main/skills/foundry-fuzz-mirrors

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 aviggiano/security --skill foundry-fuzz-mirrors -a codex

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

GitHub CLI

$ gh skill install aviggiano/security foundry-fuzz-mirrors --agent codex

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

Manual copy

$ git clone --depth 1 https://github.com/aviggiano/security.git skills-src && mkdir -p .agents/skills && cp -r skills-src/skills/foundry-fuzz-mirrors .agents/skills/foundry-fuzz-mirrors && 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 "foundry-fuzz-mirrors" agent skill from https://github.com/aviggiano/security/tree/main/skills/foundry-fuzz-mirrors into .agents/skills/foundry-fuzz-mirrors/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "foundry-fuzz-mirrors", 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 aviggiano/security --skill foundry-fuzz-mirrors -a cursor

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

GitHub CLI

$ gh skill install aviggiano/security foundry-fuzz-mirrors --agent cursor

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

Manual copy

$ git clone --depth 1 https://github.com/aviggiano/security.git skills-src && mkdir -p .cursor/skills && cp -r skills-src/skills/foundry-fuzz-mirrors .cursor/skills/foundry-fuzz-mirrors && 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 "foundry-fuzz-mirrors" agent skill from https://github.com/aviggiano/security/tree/main/skills/foundry-fuzz-mirrors into .cursor/skills/foundry-fuzz-mirrors/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "foundry-fuzz-mirrors", 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/aviggiano/security.git --path skills/foundry-fuzz-mirrors

--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 aviggiano/security --skill foundry-fuzz-mirrors -a gemini-cli

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

GitHub CLI

$ gh skill install aviggiano/security foundry-fuzz-mirrors --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/aviggiano/security.git skills-src && mkdir -p .gemini/skills && cp -r skills-src/skills/foundry-fuzz-mirrors .gemini/skills/foundry-fuzz-mirrors && 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 "foundry-fuzz-mirrors" agent skill from https://github.com/aviggiano/security/tree/main/skills/foundry-fuzz-mirrors into .gemini/skills/foundry-fuzz-mirrors/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "foundry-fuzz-mirrors", 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 aviggiano/security foundry-fuzz-mirrors

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 aviggiano/security --skill foundry-fuzz-mirrors -a github-copilot

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

Manual copy

$ git clone --depth 1 https://github.com/aviggiano/security.git skills-src && mkdir -p .github/skills && cp -r skills-src/skills/foundry-fuzz-mirrors .github/skills/foundry-fuzz-mirrors && 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 "foundry-fuzz-mirrors" agent skill from https://github.com/aviggiano/security/tree/main/skills/foundry-fuzz-mirrors into .github/skills/foundry-fuzz-mirrors/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "foundry-fuzz-mirrors", 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 aviggiano/security --skill foundry-fuzz-mirrors -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 aviggiano/security foundry-fuzz-mirrors --agent opencode

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

Manual copy

$ git clone --depth 1 https://github.com/aviggiano/security.git skills-src && mkdir -p .opencode/skills && cp -r skills-src/skills/foundry-fuzz-mirrors .opencode/skills/foundry-fuzz-mirrors && 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 "foundry-fuzz-mirrors" agent skill from https://github.com/aviggiano/security/tree/main/skills/foundry-fuzz-mirrors into .opencode/skills/foundry-fuzz-mirrors/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "foundry-fuzz-mirrors", 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: foundry-fuzz-mirrors
GitHub stars: 144
Token cost: ~584 tokens
SKILL.md length: 255 words
Files: 2
Skills in repo: 10
Repo updated: Sep 15, 2026
First seen: Oct 7, 2026
Licence: MIT

At a glance

Create Foundry fuzz tests from deterministic unit tests. An agent skill from aviggiano/security.

Works in 7 steps: Read AGENTS.md, BaseTest, BaseFuzzTest,… → Enumerate public user actions and… → Create one fuzz test contract per action… → …
Codex needs to mirror unit-test flows as parametric fuzz tests
SKILL.md covers Workflow, Test Families, Bounding Rules and Failure Policy
Instructions only: no scripts, shell commands, URLs or credentials in SKILL.md

What it does

Foundry Fuzz Mirrors is an agent skill from aviggiano/security. Create Foundry fuzz tests from deterministic unit tests. Use when Codex needs to mirror unit-test flows as parametric fuzz tests, add bounded inputs, expected-vs-actual assertions, quote/execution checks, exact-in/out cases, partial fills, and rounding-sensitive tests without changing production contracts.

Its SKILL.md is about 580 tokens, which your agent loads only when the skill is triggered. The skill folder holds 2 other files (for example `agents/openai.yaml`).

It sits in Testing & QA, covering Unit testing and Fuzzing. The repository describes itself as: Security Reviews and Audit Checklists. The licence is MIT.

When your agent uses it

Codex needs to mirror unit-test flows as parametric fuzz tests
Add bounded inputs
Expected-vs-actual assertions
Quote/execution checks

Example prompts

“/foundry-fuzz-mirrors”

Workflow steps

7 steps, taken from the first numbered list in SKILL.md.

Read AGENTS.md, BaseTest, BaseFuzzTest, and deterministic unit tests.
Enumerate public user actions and behavior branches before editing.
Create one fuzz test contract per action or surface, matching existing naming and directory style.
Parameterize the same scenario the unit test proves.
Add semantic bound helpers to BaseFuzzTest when the bound is reused.
Assert observable public state, balances, return values, and events only when the repo already tests events.
Run the focused fuzz contract, then the relevant suite.

What it can do on your machine

Read from SKILL.md and the folder at commit e18ce7d. 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 solidity).
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 no API keys, tokens, secrets or passwords.
From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.

Context cost

Foundry Fuzz Mirrors loads about 584 tokens when it runs. Until then it costs about 82 tokens; SKILL.md has 255 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it: ~82
When it runs · the whole SKILL.md, loaded when a task matches: ~584

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 aviggiano/security at commit e18ce7d, republished under its MIT licence (© aviggiano). 255 words, ~584 tokens.

Download SKILL.mdSave it as .claude/skills/foundry-fuzz-mirrors/SKILL.md (or your agent's skills folder). This skill also uses 1 other file; get the full folder from GitHub.

name: foundry-fuzz-mirrors
description: Create Foundry fuzz tests from deterministic unit tests. Use when Codex needs to mirror unit-test flows as parametric fuzz tests, add bounded inputs, expected-vs-actual assertions, quote/execution checks, exact-in/out cases, partial fills, and rounding-sensitive tests without changing production contracts.

Foundry Fuzz Mirrors

Workflow

Read AGENTS.md, BaseTest, BaseFuzzTest, and deterministic unit tests.
Enumerate public user actions and behavior branches before editing.
Create one fuzz test contract per action or surface, matching existing naming and directory style.
Parameterize the same scenario the unit test proves.
Add semantic bound helpers to BaseFuzzTest when the bound is reused.
Assert observable public state, balances, return values, and events only when the repo already tests events.
Run the focused fuzz contract, then the relevant suite.

Test Families

Prefer these families before broad stateful fuzzing:

expected == actual: quote result vs execution result, preview vs actual, returned amounts vs balance deltas.
exact input and exact output: include both sides when the interface exposes both.
partial fills: generate enough liquidity to guarantee a partial path.
boundary and rounding: min size, dust-adjacent values, decimals, fees, rebates, slippage limits.
roundtrip invariants: quote then execute, exact-output then exact-input, create-decrease-cancel, deposit-withdraw, add-remove liquidity.

Bounding Rules

Bound inputs to valid preconditions, not to make assertions pass. If a precondition is part of the property, assert or vm.assume it explicitly. Keep edge values in range whenever they are semantically valid.

Use helper names that explain domain meaning:

solidity

uint256 amount = _boundQuoteAmount(amountSeed);
uint256 price = _boundPrice(priceSeed);
uint256 size = _boundSellSize(sizeSeed, price);

Failure Policy

If a fuzz test fails, do not immediately change production code or weaken the test. First isolate whether the failure is:

invalid harness setup
ambiguous spec expectation
rounding/spec mismatch
production behavior bug

When a single assertion is ambiguous, add a narrower sibling test that keeps the setup but checks only the disputed relationship.

Files

SKILL.md and 1 other file in skills/foundry-fuzz-mirrors of aviggiano/security.

SKILL.md
agents/openai.yaml

Open the folder on GitHubat commit e18ce7d

Compare with similar skills

Foundry Fuzz Mirrors 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.

Foundry Fuzz Mirrors compared with similar skills
Skill	Stars	Used in	Tokens	Auto-check	Licence	Repo updated
Foundry Fuzz Mirrors this skillaviggiano/security	144	—	~584	Automated safety check: Pass	MIT	25 days ago
Testingstatic-web-server/static-web-server	2.4k	—	~2.1k	Automated safety check: Pass	Apache-2.0	yesterday
Testingaustintgriffith/ethskills	295	—	~3.1k	Automated safety check: Pass	None	1 mo ago
Kernel Testingmohitmishra786/low-level-dev-skills	252	—	~1.4k	Automated safety check: Pass	MIT	3 mo ago
TDD WorkflowhellangleZ/burn-in-cceverywhere-ralph	112	11 repos	~2.4k	Automated safety check: Pass	None	8 mo ago
Testing OpenLogi UIAprilNEA/OpenLogi	23k	—	~1.1k	Automated safety check: Pass	Apache-2.0	today

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Questions about Foundry Fuzz Mirrors

What does Foundry Fuzz Mirrors do?

Create Foundry fuzz tests from deterministic unit tests. An agent skill from aviggiano/security. Foundry Fuzz Mirrors is an agent skill from aviggiano/security. Create Foundry fuzz tests from deterministic unit tests.

When should I use Foundry Fuzz Mirrors?

Foundry Fuzz Mirrors fits situations like: Codex needs to mirror unit-test flows as parametric fuzz tests; add bounded inputs; expected-vs-actual assertions; quote/execution checks.

How do I install Foundry Fuzz Mirrors in Claude Code?

Run `npx skills add aviggiano/security --skill foundry-fuzz-mirrors -a claude-code`. Or copy the skill folder (skills/foundry-fuzz-mirrors in aviggiano/security) into .claude/skills/foundry-fuzz-mirrors in your project. Claude Code loads it when a task matches its description.

How do I install Foundry Fuzz Mirrors in Codex?

Run `npx skills add aviggiano/security --skill foundry-fuzz-mirrors -a codex`. Or copy the skill folder (skills/foundry-fuzz-mirrors in aviggiano/security) into .agents/skills/foundry-fuzz-mirrors in your project. Codex loads it when a task matches its description.

Can I use Foundry Fuzz Mirrors 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 aviggiano/security --skill foundry-fuzz-mirrors -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/foundry-fuzz-mirrors, .gemini/skills/foundry-fuzz-mirrors, .github/skills/foundry-fuzz-mirrors and .opencode/skills/foundry-fuzz-mirrors in your project.

What does Foundry Fuzz Mirrors need to run?

SKILL.md names no scripts, command-line tools or credentials: Foundry Fuzz Mirrors is instructions for the agent only.

Does Foundry Fuzz Mirrors 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 Foundry Fuzz Mirrors 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 Foundry Fuzz Mirrors use?

Foundry Fuzz Mirrors 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 Foundry Fuzz Mirrors use?

About 584 tokens (SKILL.md is roughly 2.3k 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 Foundry Fuzz Mirrors?

Skills that share tags, products or a category with Foundry Fuzz Mirrors: Testing (static-web-server/static-web-server, 2.4k stars), Testing (austintgriffith/ethskills, 295 stars), Kernel Testing (mohitmishra786/low-level-dev-skills, 252 stars) and TDD Workflow (hellangleZ/burn-in-cceverywhere-ralph, 112 stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.

Who maintains Foundry Fuzz Mirrors?

aviggiano (a GitHub user) maintains it in aviggiano/security, which has 144 GitHub stars. The repository holds 10 skills in this directory. The repository was last updated on September 15, 2026.

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

Foundry Fuzz Mirrors

Install Foundry Fuzz Mirrors

Facts

At a glance

What it does

When your agent uses it

Example prompts

Workflow steps

What it can do on your machine

Tool permissions

Runs code

Network

Credentials

Context cost

Safety

SKILL.md

Foundry Fuzz Mirrors

Workflow

Test Families

Bounding Rules

Failure Policy

Files

Compare with similar skills

Similar skills

Testing

Testing

Kernel Testing

TDD Workflow

Testing OpenLogi UI

Go Testing

More from aviggiano/security

Foundry Deploy Fixtures

Foundry Spec Properties

Foundry Test Campaign

Stateful Invariant Testing

Foundry Differential Tests

Foundry Failure Triage

Questions about Foundry Fuzz Mirrors

Install Foundry Fuzz Mirrors

Facts

At a glance

What it does

When your agent uses it

Example prompts

Workflow steps

What it can do on your machine

Tool permissions

Runs code

Network

Credentials

Context cost

Safety

SKILL.md

Foundry Fuzz Mirrors

Workflow

Test Families

Bounding Rules

Failure Policy

Files

Compare with similar skills

Similar skills

More from aviggiano/security

Related

Questions about Foundry Fuzz Mirrors