performance

A set of rules for organizing and writing performance tests, which measure how software behaves under different levels of use. It covers load tests for APIs such as JSONPlaceholder, ReqRes.in, and HTTPBin using Artillery and Playwright.

In plain words
What is it for?
Use it to create API load, stress, spike, and recovery tests. It helps organize configuration files, JavaScript test logic, and Playwright test wrappers.
Why use it?
It gives performance tests a consistent structure and naming system, making them easier to find, run, and compare. It also defines stages such as warm-up, sustained use, and ramp-up for more realistic results.

Cursor rule for Cursor

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.

agentmods
npx agentmods add rules/m3au/playwright-bdd-cursor-template/performance
Clone the repo
git clone --depth 1 https://github.com/m3au/playwright-bdd-cursor-template

Made for: Cursor.

Per session 0 Nothing until a file matches its globs; then the whole rule loads.
When invoked 1,453 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
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.

ModelPer sessionOnce invoked
Fable 5 $0.00000 $0.01453
Opus 5 $0.00000 $0.00727
Sonnet 5 $0.00000 $0.00291
Haiku 4.5 $0.00000 $0.00145

Measured yesterday against content hash ad202d689a60, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

performance 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 yesterday.

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.

.cursor/rules/performance.mdc · 221 lines

How it starts

The opening of the file, as written. The whole thing — 221 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Performance Testing Standards

Performance Test Organization

Performance tests are organized by challenge in tests/performance/challenges/:

  • tests/performance/challenges/jsonplaceholder/ - JSONPlaceholder API load tests
  • tests/performance/challenges/reqres/ - ReqRes.in API load tests
  • tests/performance/challenges/httpbin/ - HTTPBin load tests

Each challenge contains:

  • config/ - Artillery YAML configuration files
  • processors/ - JavaScript processor files with flow functions
  • *.load.spec.ts - Playwright test wrappers

Artillery Configuration Standards

Naming

  • Use descriptive names for phases and scenarios
  • Prefix config files with resource name (e.g., posts-load.yml)
  • Use kebab-case for file names

Phases

  • Always include warm-up phase (30-60 seconds, low arrival rate)
  • Include sustained load phase (60-120 seconds, normal arrival rate)
  • Include ramp-down phase (15-30 seconds, zero arrival rate)
  • For stress tests, include high-load phase
  • For spike tests, include spike and recovery phases

Arrival Rates

  • Start with low rates (1-2 users/second)
  • Gradually increase to normal rates (5-10 users/second)
  • For stress tests, increase to maximum capacity (20+ users/second)
  • For spike tests, simulate sudden increases (30+ users/second)

Timeouts

  • Set appropriate timeouts for requests (default: 30s)
  • Consider network latency and response times

Metrics

  • Enable expect plugin for assertions
  • Enable metrics-by-endpoint for detailed metrics

Processors

  • Extract reusable logic to processor files
  • Use descriptive function names
  • Validate all responses before returning

Processor Function Standards

Error Handling

  • Always check response status codes
  • Throw descriptive errors with status codes
  • Validate response structure before returning

Response Validation

  • Validate response structure matches expected format
  • Check for required fields
  • Validate data types

Data Usage

  • Use realistic test data
  • Add randomness to simulate real users
  • Use timestamps or unique identifiers where appropriate

Read the full file on GitHub · 221 lines

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.

  1. yesterday First seen · 221 lines · 0 tokens per session scan A ad202d689a60

Subscribe to this mod's changes

performance is a cursor rule published in the GitHub repository m3au/playwright-bdd-cursor-template (2 stars, last pushed 6mo ago), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 1,453 tokens. 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 2026-08-31.