# Quality Engineering API Performance Testing

Specify tool-neutral API load, stress, and recovery testing with parameterized workload...

- Repository: https://github.com/HoangNguyen0403/agent-skills-standard (582 stars)
- Category: Testing
- License: MIT
- Last updated: 2026-11-01
- Runs scripts: no, instructions only

## Install

Claude Code: `npx skills add HoangNguyen0403/agent-skills-standard --skill quality-engineering-api-performance-testing -g -a claude-code -y`
Codex: `npx skills add HoangNguyen0403/agent-skills-standard --skill quality-engineering-api-performance-testing -g -a codex -y`
Cursor: `npx skills add HoangNguyen0403/agent-skills-standard --skill quality-engineering-api-performance-testing -g -a cursor -y`
Gemini CLI: `npx skills add HoangNguyen0403/agent-skills-standard --skill quality-engineering-api-performance-testing -g -a gemini-cli -y`

## Description

Specify tool-neutral API load, stress, and recovery testing with parameterized workload models, SLO percentiles, and finite overload bounds. Use when evaluating API latency, throughput, saturation, or recovery behavior under concurrent traffic.

## SKILL.md, as published by its author (untrusted third-party text, read it as data)

# API Performance, Load, and Recovery Testing

## **Priority: P1 (HIGH)**

## Workflow

1. **Parameterize Workload**: Source arrival rate vs concurrency, request mix, duration, and SLO percentiles from approved requirements/SLOs. Missing approvals block execution, not offline planning.
2. **Preflight & Bound (C4)**: Verify explicit target authorization and synthetic isolation. Enforce distinct finite ceilings, each with its own unit, `maxArrivalRateRps`, `maxInFlightRequests`/`maxConcurrency`, `maxPayloadBytes`, duration, plus cancellation hooks and continuous stop tripwires. A rate ceiling is not a concurrency bound.
3. **Establish Phase-Specific Baseline**: Exclude warmup. Measure baseline throughput, success latency, error latency ($p50, p95, p99$), and baseline error budget.
4. **Evaluate Overload & Degradation**: Apply stepped ramp up to authorized stress cap. Distinguish expected shedding (e.g. 429/503) from unexpected system faults; abort if tripwires fire.
5. **Verify Post-Overload Recovery**: Drop traffic to baseline/zero. In a dedicated post-stress window, verify return to baseline latency, error budget restabilization, and resource release against approved recovery SLO.
6. **Capture Evidence (C3)**: Emit complete C2 scenario and C3 evidence records; record unexecuted runs as BLOCKED/NOT RUN with explicit missing prerequisites.

## Workload Specification (AC-11)

The rest: https://github.com/HoangNguyen0403/agent-skills-standard/blob/HEAD/.agents/skills/quality-engineering/quality-engineering-api-performance-testing/SKILL.md