Agent skill

Fs Fixture

by privatenumber in privatenumber/fs-fixture

Create disposable file system test fixtures from objects, templates, or empty directories with automatic cleanup.

MITAuto-check passedTesting & QA

Install Fs Fixture

skills CLI

$ npx skills add privatenumber/fs-fixture --skill fs-fixture -a claude-code

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

GitHub CLI

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

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 privatenumber/fs-fixture --skill fs-fixture -a codex

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

GitHub CLI

$ gh skill install privatenumber/fs-fixture fs-fixture --agent codex

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

Manual copy

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

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

GitHub CLI

$ gh skill install privatenumber/fs-fixture fs-fixture --agent cursor

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

Manual copy

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

--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 privatenumber/fs-fixture --skill fs-fixture -a gemini-cli

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

GitHub CLI

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

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 privatenumber/fs-fixture --skill fs-fixture -a github-copilot

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

Manual copy

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

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

Manual copy

$ git clone --depth 1 https://github.com/privatenumber/fs-fixture.git skills-src && mkdir -p .opencode/skills && cp -r skills-src/skills/fs-fixture .opencode/skills/fs-fixture && 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 "fs-fixture" agent skill from https://github.com/privatenumber/fs-fixture/tree/master/skills/fs-fixture into .opencode/skills/fs-fixture/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "fs-fixture", 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: fs-fixture
GitHub stars: 100
Token cost: ~1.2k tokens
SKILL.md length: 345 words
Files: 1
Skills in repo: 1
Repo updated: Sep 3, 2026
First seen: Oct 7, 2026
Licence: MIT

At a glance

Create disposable file system test fixtures from objects, templates, or empty directories with automatic cleanup.

Writing tests that need temporary files
SKILL.md covers Quick Start, createFixture(source?, options?), FsFixture Methods and FileTree Values, plus 2 more sections
Instructions only: no scripts, shell commands, URLs or credentials in SKILL.md
JSON fixtures on disk

What it does

Fs Fixture is an agent skill from privatenumber/fs-fixture. Create disposable file system test fixtures from objects, templates, or empty directories with automatic cleanup. Use when writing tests that need temporary files, directories, symlinks, or JSON fixtures on disk. Keywords - fs, tmp, temp, fixture, testing utility, cleanup, dispose.

Its SKILL.md is about 1.2k tokens, which your agent loads only when the skill is triggered. It is a single SKILL.md file with no bundled scripts.

It sits in Testing & QA, covering Test data and fixtures. The repository describes itself as: Simple API to create test fixtures on disk. The licence is MIT.

When your agent uses it

Writing tests that need temporary files
JSON fixtures on disk

Example prompts

“/fs-fixture”

What it can do on your machine

Read from SKILL.md and the folder at commit 121f1b9. 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 typescript).
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

Fs Fixture loads about 1.2k tokens when it runs. Until then it costs about 73 tokens; SKILL.md has 345 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it: ~73
When it runs · the whole SKILL.md, loaded when a task matches: ~1.2k

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 privatenumber/fs-fixture at commit 121f1b9, republished under its MIT licence (© privatenumber). 345 words, ~1,180 tokens.

Download SKILL.mdSave it as .claude/skills/fs-fixture/SKILL.md (or your agent's skills folder).

name: fs-fixture
description: Create disposable file system test fixtures from objects, templates, or empty directories with automatic cleanup. Use when writing tests that need temporary files, directories, symlinks, or JSON fixtures on disk. Keywords - fs, tmp, temp, fixture, testing utility, cleanup, dispose.

Quick Start

import { createFixture } from 'fs-fixture'

// From object — keys are paths, values are content
const fixture = await createFixture({
    'package.json': JSON.stringify({ name: 'test' }),
    'src/index.js': 'export default 42',
})

// Use fixture.path, fixture.readFile(), etc.
await fixture.rm() // Cleanup when done

Auto-cleanup with using (TypeScript 5.2+):

await using fixture = await createFixture({ 'file.txt': 'content' })
// Automatically cleaned up when scope exits

createFixture(source?, options?)

Source	Behavior
`{ path: content }`	Create files from object. Nested objects create directories.
`'./path'`	Copy template directory into fixture
`(fixture) => ...`	Run complex, imperative, or ordered setup and optionally return a FileTree
(omitted)	Empty temporary directory

Option	Type	Default	Description
`tempDir`	`string \| URL`	`os.tmpdir()`	Custom parent directory
`templateFilter`	`(src, dest) => boolean`	—	Filter files when copying template

FsFixture Methods

Method	Description
`fixture.path`	Absolute path to fixture root
`getPath(...paths)`	Resolve path relative to fixture root
`exists(path?)`	Check existence (returns `boolean`)
`readFile(path, encoding?)`	Read file — `'utf8'` returns `string`, omit for `Buffer`
`writeFile(path, content)`	Write string or Buffer
`readJson<T>(path)`	Read and parse JSON with type parameter
`writeJson(path, data, space?)`	Write JSON (default: 2-space indent, `0` for minified)
`readdir()`, `readdir(path, options?)`	List fixture root or directory. Pass `''` for root options. `{ withFileTypes: true }` returns Dirent[].
`mkdir(path)`	Create directory recursively
`cp(source, dest?)`	Copy external file/directory into fixture
`mv(source, dest)`	Move or rename within fixture
`rm(path?)`	Delete path, or entire fixture if omitted

FileTree Values

Type	Example
`string`	`'file content'`
`Buffer`	`Buffer.from([0x89, 0x50])`
Nested object	`{ dir: { 'file.txt': 'content' } }`
Function	`({ fixturePath, filePath, getPath, symlink }) => symlink('./target')`

Path syntax — these are equivalent:

// Nested objects
{ src: { utils: { 'helper.js': 'code' } } }

// Slash-separated keys
{ 'src/utils/helper.js': 'code' }

[!TIP] Slash-separated keys can also group a shared prefix:

await createFixture({
    'file.js': 'import { a } from "my-pkg";',

    'node_modules/my-pkg': {
        'package.json': JSON.stringify({
            name: 'my-pkg',
            type: 'module',
            exports: './index.js'
        }),
        'index.js': 'export const a = 1;'
    }
})

Patterns

Choosing a source

Prefer a FileTree for files and directories.
Use an initializer function for complex, imperative, or ordered setup, such as initializing a Git repository or running a project setup helper.
Return a FileTree from an initializer for declarative files that should be created after setup completes.
Use a FileTree entry function for isolated dynamic file content.

Symlinks

const fixture = await createFixture({
    'target.txt': 'real file',
    'link.txt': ({ symlink }) => symlink('./target.txt'),
    'node_modules/pkg': ({ symlink }) => symlink(process.cwd()),
})

Dynamic content

const fixture = await createFixture({
    'info.txt': ({ fixturePath }) => `Root: ${fixturePath}`,
})

Initialization

const fixture = await createFixture(async ({ path, writeJson }) => {
    await writeJson('package.json', { name: 'test-package' })

    // Test-specific setup that needs the fixture path.
    await initializeProject(path)

    return {
        'src/index.js': 'export default 42',
    }
})

The initializer receives the fixture before it is returned. It contains setup with the fixture it configures and can return a FileTree to create after setup completes. Returned files overwrite regular files created during setup, but the tree does not replace the fixture directory. If setup fails, fs-fixture removes the fixture before it rethrows the error.

Commonly used with manten test framework.

Files

Just SKILL.md in skills/fs-fixture of privatenumber/fs-fixture.

Open the folder on GitHubat commit 121f1b9

Compare with similar skills

Fs Fixture 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.

Fs Fixture compared with similar skills
Skill	Stars	Used in	Tokens	Auto-check	Licence	Repo updated
Fs Fixture this skillprivatenumber/fs-fixture	100	—	~1.2k	Automated safety check: Pass	MIT	1 mo ago
Dev Tenant APInightscout/nocturne	139	—	~1.4k	Automated safety check: Pass	None	today
Rsibench Data Factoryevolvent-ai/RSIBench-Data	171	—	~640	Automated safety check: Notes	None	1 mo ago
Eval Designagentscope-ai/OpenJudge	871	—	~2.8k	Automated safety check: Warn	Apache-2.0	1 mo ago
Data GenerationRed-Hat-AI-Innovation-Team/sdg_hub	164	—	~381	Automated safety check: Pass	Apache-2.0	2 days ago
Migrate Mstest V1v2 To V3dotnet/skills	5.6k	1 repos	~5.5k	Automated safety check: Pass	MIT	yesterday

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Questions about Fs Fixture

What does Fs Fixture do?

Create disposable file system test fixtures from objects, templates, or empty directories with automatic cleanup. Fs Fixture is an agent skill from privatenumber/fs-fixture. Create disposable file system test fixtures from objects, templates, or empty directories with automatic cleanup.

When should I use Fs Fixture?

Fs Fixture fits situations like: writing tests that need temporary files; JSON fixtures on disk.

How do I install Fs Fixture in Claude Code?

Run `npx skills add privatenumber/fs-fixture --skill fs-fixture -a claude-code`. Or copy the skill folder (skills/fs-fixture in privatenumber/fs-fixture) into .claude/skills/fs-fixture in your project. Claude Code loads it when a task matches its description.

How do I install Fs Fixture in Codex?

Run `npx skills add privatenumber/fs-fixture --skill fs-fixture -a codex`. Or copy the skill folder (skills/fs-fixture in privatenumber/fs-fixture) into .agents/skills/fs-fixture in your project. Codex loads it when a task matches its description.

Can I use Fs Fixture 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 privatenumber/fs-fixture --skill fs-fixture -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/fs-fixture, .gemini/skills/fs-fixture, .github/skills/fs-fixture and .opencode/skills/fs-fixture in your project.

What does Fs Fixture need to run?

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

Does Fs Fixture 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 Fs Fixture 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 Fs Fixture use?

Fs Fixture 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 Fs Fixture use?

About 1.2k tokens (SKILL.md is roughly 4.7k 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 Fs Fixture?

Skills that share tags, products or a category with Fs Fixture: Dev Tenant API (nightscout/nocturne, 139 stars), Rsibench Data Factory (evolvent-ai/RSIBench-Data, 171 stars), Eval Design (agentscope-ai/OpenJudge, 871 stars) and Data Generation (Red-Hat-AI-Innovation-Team/sdg_hub, 164 stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.

Who maintains Fs Fixture?

privatenumber (a GitHub user) maintains it in privatenumber/fs-fixture, which has 100 GitHub stars. The repository was last updated on September 3, 2026.

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

Install Fs Fixture

Facts

At a glance

What it does

When your agent uses it

Example prompts

What it can do on your machine

Tool permissions

Runs code

Network

Credentials

Context cost

Safety

SKILL.md

Quick Start

createFixture(source?, options?)

FsFixture Methods

FileTree Values

Patterns

Choosing a source

Symlinks

Dynamic content

Initialization

Related

Files

Compare with similar skills

Similar skills

Dev Tenant API

Rsibench Data Factory

Eval Design

Data Generation

Migrate Mstest V1v2 To V3

App Verification

Related

Questions about Fs Fixture