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Performance tester

Skill AtulPurohit/Antigravity-Awesome-Skills/plugins/dx-qa-automation/skills/performance-tester

Installable GitHub library of 300+ professional agentic skills for Claude Code, Antigravity IDE, Gemini CLI, Cursor, and Copilot. Features a custom NPX installer, 9 stack-specific bundles, validation schemas, security auditing, and an interactive catalog explorer app.

Install
npx -y skills add AtulPurohit/Antigravity-Awesome-Skills --skill performance-tester

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What its author says it does

Copied from the file, not written here

Design and run performance tests to identify bottlenecks, validate SLOs, and measure system capacity. Covers load tests, stress tests, and spike tests.

SKILL.md

2.8 KB, 634 tokens by cl100k_base, as published. Nobody here has run it

Performance Tester

Purpose

Identify performance bottlenecks and validate that systems meet SLOs under realistic and extreme load conditions.

Performance Test Types

TypeGoalWhen
Load testValidate normal trafficBefore release
Stress testFind breaking pointCapacity planning
Spike testHandle sudden trafficEvent preparation
Soak testFind memory leaksLong-running validation
Smoke testBasic sanity checkAfter deploy

k6 Test Scripts

import http from 'k6/http';
import { check, sleep } from 'k6';
import { Rate, Trend } from 'k6/metrics';

const errorRate = new Rate('errors');
const apiDuration = new Trend('api_duration');

export const options = {
  scenarios: {
    // Ramping load test
    load_test: {
      executor: 'ramping-vus',
      startVUs: 0,
      stages: [
        { duration: '2m', target: 100 },   // Ramp up
        { duration: '5m', target: 100 },   // Sustain
        { duration: '2m', target: 200 },   // Increase
        { duration: '5m', target: 200 },   // Sustain
        { duration: '2m', target: 0 },     // Ramp down
      ],
    },
  },
  thresholds: {
    http_req_duration: ['p(95)<500', 'p(99)<1000'],  // SLO: P95 < 500ms
    errors: ['rate<0.01'],                             // Error rate < 1%
    http_req_failed: ['rate<0.01'],
  },
};

export default function() {
  const res = http.get('https://api.example.com/posts', {
    headers: { Authorization: `Bearer ${__ENV.API_TOKEN}` },
  });

  const success = check(res, {
    'status is 200': (r) => r.status === 200,
    'response time < 500ms': (r) => r.timings.duration < 500,
    'has data': (r) => r.json().data !== undefined,
  });

  errorRate.add(!success);
  apiDuration.add(res.timings.duration);

  sleep(1);
}

Identifying Bottlenecks

# Profile running Node.js app
node --prof app.js

# Analyze flame graph
npx clinic flame -- node server.js

# Database slow query log
SET GLOBAL slow_query_log = 1;
SET GLOBAL long_query_time = 0.1;

# Profile PostgreSQL queries
EXPLAIN (ANALYZE, BUFFERS, FORMAT JSON) SELECT ...;

Outputs

  1. k6 test scripts for all scenarios
  2. SLO definition (P95, P99 targets)
  3. Performance baseline report
  4. Bottleneck analysis
  5. Optimization recommendations
  6. Continuous performance monitoring setup

What ships with it

Read from the repository

Just SKILL.md. No reference files, no scripts.

Keep looking

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