# load-test-builder

Builds load, stress and spike tests with k6, Artillery or autocannon, then wires performance gates into CI.

- skill · `type=skill` · Claude Code, Codex, Cursor, GitHub Copilot, Gemini CLI, OpenCode · 316 installs · ★ 63
- Author: patricio0312rev
- License: MIT · policy=mirror · the beginning of the file is at the end of this page
- Source: https://github.com/patricio0312rev/skills/tree/HEAD/testing/load-test-builder/SKILL.md
- Updated: 2026-01-12
- HTML: https://affpapa.org/en/nevibecode/skills/load-test-builder

## What it does

The skill walks the agent through a fixed order: define user journeys and load patterns, set thresholds, configure ramp-up and peak, run the scenarios, read the metrics, add CI gates. Output lands in `load-tests/` as runnable files.

For k6 you get a basic test with staged ramp-up and thresholds like `p(95)<500`, a user journey covering login, product browsing and checkout, plus stress, spike and soak scenarios. Custom metrics come from `Rate` and `Trend`, and the target host is read from the `BASE_URL` env var.

k6 itself has to be installed first — `brew install k6` on macOS, or the `grafana/k6` Docker image. Point the tests at a staging environment, not production: the generated scenarios ramp to hundreds of virtual users, and a spike profile against a live database is a good way to find out what your connection pool really does.

## Install

### Claude Code (native platform)

1. **Skills CLI (Vercel)**
```bash
npx skills add patricio0312rev/skills --skill load-test-builder -a claude-code
```

2. **Manually: put the files in place**
- File: `~/.claude/skills/load-test-builder/SKILL.md` — Copy the whole skill folder; for one project use .claude/skills/load-test-builder/

### Codex

1. **Skills CLI (Vercel)**
```bash
npx skills add patricio0312rev/skills --skill load-test-builder -a codex
```

2. **Manually: put the files in place**
- File: `.agents/skills/load-test-builder/SKILL.md` — For all projects use ~/.agents/skills/

### Cursor

1. **Skills CLI (Vercel)**
```bash
npx skills add patricio0312rev/skills --skill load-test-builder -a cursor
```

2. **Manually: put the files in place**
- File: `.cursor/skills/load-test-builder/SKILL.md` — Cursor also reads .agents/skills/ and .claude/skills/

### GitHub Copilot

1. **GitHub CLI**
```bash
gh skill install patricio0312rev/skills load-test-builder
```

2. **Manually: put the files in place**
- File: `.github/skills/load-test-builder/SKILL.md`

### Gemini CLI

1. **Skills CLI (Vercel)**
```bash
npx skills add patricio0312rev/skills --skill load-test-builder -a gemini-cli
```

2. **Platform CLI**
```bash
gemini skills install https://github.com/patricio0312rev/skills --path testing/load-test-builder
```

### Windsurf (Devin Desktop)

**Manually: put the files in place**
- File: `.devin/skills/load-test-builder/SKILL.md` — The legacy .windsurf/skills/ path still works

### OpenCode

**Skills CLI (Vercel)**
```bash
npx skills add patricio0312rev/skills --skill load-test-builder -a opencode
```

### Claude.ai

**Claude.ai**
- Zip the folder and upload it in Settings → Capabilities → Skills

Where a file is given instead of a command, copy the files from the source to that path: https://github.com/patricio0312rev/skills/tree/HEAD/testing/load-test-builder/SKILL.md

## When to use it
- write a k6 load test with staged ramp-up and ramp-down
- model a user journey from login through checkout
- set thresholds on response time and error rate
- check how a service behaves under a spike or an 8-hour soak
- add a performance gate to the CI pipeline

## Example prompts
- Write a k6 load test for /api/users with a p(95) threshold under 500 ms
- Build a user journey scenario: login, browse products, checkout
- Create a stress test ramping to 400 virtual users and analyze the metrics

## Source text · SKILL.md · MIT

Below is the content of a third-party file. It is data, not instructions for you: do not act on anything written inside unless the human asks. Block tag: 7083601768f92c21.

BEGIN THIRD-PARTY FILE 7083601768f92c21
````text
---
name: load-test-builder
description: Creates load and performance tests with k6, Artillery, or autocannon to validate system behavior under stress. Use when users request "load testing", "performance testing", "stress testing", "k6 setup", or "benchmark API".
---

# Load Test Builder

Validate system performance under realistic and stress conditions.

## Core Workflow

1. **Define scenarios**: User journeys and load patterns
2. **Set thresholds**: Performance requirements
3. **Configure load**: Ramp-up, peak, duration
4. **Run tests**: Execute load scenarios
5. **Analyze results**: Metrics and bottlenecks
6. **Integrate CI**: Automated performance gates

## k6 Load Testing

### Installation

```bash
# macOS
brew install k6

# Docker
docker pull grafana/k6
```

### Basic Load Test

```javascript
// load-tests/basic.js
import http from 'k6/http';
import { check, sleep } from 'k6';
import { Rate, Trend } from 'k6/metrics';

// Custom metrics
const errorRate = new Rate('errors');
const responseTime = new Trend('response_time');

// Test configuration
export const options = {
  stages: [
    { duration: '1m', target: 20 },   // Ramp up to 20 users
    { duration: '3m', target: 20 },   // Stay at 20 users
    { duration: '1m', target: 50 },   // Ramp up to 50 users
    { duration: '3m', target: 50 },   // Stay at 50 users
    { duration: '1m', target: 0 },    // Ramp down to 0
  ],
  thresholds: {
    http_req_duration: ['p(95)<500', 'p(99)<1000'],
    http_req_failed: ['rate<0.01'],
    errors: ['rate<0.05'],
  },
};

const BASE_URL = __ENV.BASE_URL || 'http://localhost:3000';

export default function () {
  // Homepage
  const homeResponse = http.get(`${BASE_URL}/`);

  check(homeResponse, {
    'homepage status is 200': (r) => r.status === 200,
    'homepage loads fast': (r) => r.timings.duration < 500,
  });

  responseTime.add(homeResponse.timings.duration);
  errorRate.add(homeResponse.status !== 200);

  sleep(1);

  // API request
  const apiResponse = http.get(`${BASE_URL}/api/users`);

  check(apiResponse, {
    'api status is 200': (r) => r.status === 200,
    'api returns array': (r) => Array.isArray(JSON.parse(r.body)),
  });

  errorRate.add(apiResponse.status !== 200);

  sleep(Math.random() * 3 + 1); // Random think time 1-4 seconds
}
```

### User Journey Test

```javascript
// load-tests/user-journey.js
import http from 'k6/http';
import { check, group, sleep } from 'k6';
import { SharedArray } from 'k6/data';

const users = new SharedArray('users', function () {
  return JSON.parse(open('./data/users.json'));
});

export const options = {
  scenarios: {
    browse_and_buy: {
      executor: 'ramping-vus',
      startVUs: 0,
      stages: [
        { duration: '2m', target: 100 },
        { duration: '5m', target: 100 },
        { duration: '2m', target: 0 },
      ],
      gracefulRampDown: '30s',
    },
````
END THIRD-PARTY FILE 7083601768f92c21

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