What is performance-testing?

A guide to measuring how an application behaves under load, including response time, request volume, resource use, and ability to handle concurrent users.

Use it for load tests, API latency checks, database benchmarks, scalability checks, and before-and-after performance comparisons.

It helps reveal bottlenecks and capacity limits before slowdowns appear in production.

performance-testing — Skill for Claude Code and Codex by aj-geddes

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Any agent

npx skills add aj-geddes/useful-ai-prompts --skill performance-testing

Clone the repo

git clone --depth 1 https://github.com/aj-geddes/useful-ai-prompts

Made for: Claude Code, Codex.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

README.md

[![agentmods](https://agentmods.dev/badge/skills/aj-geddes/useful-ai-prompts/performance-testing/github.svg)](https://agentmods.dev/skills/aj-geddes/useful-ai-prompts/performance-testing)

Your own site

<a href="https://agentmods.dev/skills/aj-geddes/useful-ai-prompts/performance-testing"><img src="https://agentmods.dev/badge/skills/aj-geddes/useful-ai-prompts/performance-testing/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

Your own site · 80×15

<a href="https://agentmods.dev/skills/aj-geddes/useful-ai-prompts/performance-testing"><img src="https://agentmods.dev/badge/skills/aj-geddes/useful-ai-prompts/performance-testing.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 42 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 757 The whole file, excluding the scripts and references it only reads on demand.

Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe. Third-party audits

Socket pass 18 Mar 2026
Snyk pass 4 Mar 2026

How audits are shown

Origin original No closer match found in the catalogue.

Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

Model	Per session	Once invoked
Fable 5.1	$0.00042	$0.00757
Opus 5	$0.00021	$0.00378
Sonnet 5	$0.00008	$0.00151
Haiku 4.5	$0.00004	$0.00076

Measured 9d ago against content hash 4ddbbefc8228, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-12, from the pricing page.

Security

Grade A, and why

performance-testing scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 9d ago.

The scan reads SKILL.md. This mod also ships 1 executable file (scripts/validate-api.sh), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

skills/performance-testing/SKILL.md · 103 lines

How it starts

The opening of the file, as written. The whole thing — 103 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Overview

Performance testing measures how systems behave under various load conditions, including response times, throughput, resource utilization, and scalability. It helps identify bottlenecks, validate performance requirements, and ensure systems can handle expected loads.

When to Use

Validating response time requirements
Measuring API throughput and latency
Testing database query performance
Identifying performance bottlenecks
Comparing algorithm efficiency
Benchmarking before/after optimizations
Validating caching effectiveness
Testing concurrent user capacity

Quick Start

Minimal working example:

// load-test.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 orderDuration = new Trend("order_duration");

// Test configuration
export const options = {
  stages: [
    { duration: "2m", target: 10 }, // Ramp up to 10 users
    { duration: "5m", target: 10 }, // Stay at 10 users
    { duration: "2m", target: 50 }, // Ramp up to 50 users
    { duration: "5m", target: 50 }, // Stay at 50 users
    { duration: "2m", target: 0 }, // Ramp down to 0
  ],
  thresholds: {
    http_req_duration: ["p(95)<500"], // 95% of requests under 500ms
    http_req_failed: ["rate<0.01"], // Error rate under 1%
    errors: ["rate<0.1"], // Custom error rate under 10%
  },
};

// ... (see reference guides for full implementation)

Reference Guides

Detailed implementations in the references/ directory:

Guide	Contents
k6 for API Load Testing	k6 for API Load Testing
Apache JMeter	Apache JMeter
pytest-benchmark for Python	pytest-benchmark for Python
JMH for Java Benchmarking	JMH for Java Benchmarking
Database Query Performance	Database Query Performance
Real-Time Monitoring	Real-Time Monitoring

Read the full file on GitHub · 103 lines

Files

What ships with it

8 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

9d ago First seen · 103 lines · 42 tokens per session scan A 4ddbbefc8228

Subscribe to this mod's changes

performance-testing is a skill published in the GitHub repository aj-geddes/useful-ai-prompts (338 stars, last pushed 6mo ago), licensed MIT. It adds 42 tokens to every session and 757 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-03.

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