A set of guidelines for making web applications load and respond efficiently. It covers page-speed measures, images, JavaScript, CSS, servers, browsers, and data loading.

Use it when improving Core Web Vitals, reducing JavaScript and CSS size, optimising images, adding caching or lazy loading, and reviewing server or client performance.

It helps address slow pages, large downloads, delayed interaction, layout movement, and inefficient database or network requests.

performance — Cursor rule for Cursor by lacymorrow/paperclip-hub

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.

Clone the repo

git clone --depth 1 https://github.com/lacymorrow/paperclip-hub

Made for: Cursor.

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/rules/lacymorrow/paperclip-hub/performance/github.svg)](https://agentmods.dev/rules/lacymorrow/paperclip-hub/performance)

Your own site

<a href="https://agentmods.dev/rules/lacymorrow/paperclip-hub/performance"><img src="https://agentmods.dev/badge/rules/lacymorrow/paperclip-hub/performance/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/rules/lacymorrow/paperclip-hub/performance"><img src="https://agentmods.dev/badge/rules/lacymorrow/paperclip-hub/performance.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 0 Nothing until a file matches its globs; then the whole rule loads.

When invoked 433 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.

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	$0.00000	$0.00433
Opus 5.5	$0.00000	$0.00173
Sonnet 5.5	$0.00000	$0.00087
Haiku 4.5	$0.00000	$0.00043

Measured yesterday against content hash dd40b6105e71, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, 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 · 97 lines

What it actually says

Performance Best Practices

Core Web Vitals

Optimize LCP (Largest Contentful Paint)
Minimize FID (First Input Delay)
Reduce CLS (Cumulative Layout Shift)
Monitor Web Vitals
Set performance budgets
Regular performance audits
Document metrics

Image Optimization

Use next/image
Implement lazy loading
Choose proper formats
Optimize image sizes
Use responsive images
Implement caching
Monitor image performance

JavaScript

Implement code splitting
Use dynamic imports
Minimize bundle size
Tree shake unused code
Optimize dependencies
Use proper caching
Monitor JS performance

CSS

Minimize unused CSS
Use CSS modules
Implement critical CSS
Optimize tailwind usage
Reduce CSS bundle size
Use proper specificity
Monitor CSS performance

Server-Side

Use proper caching
Optimize database queries
Implement CDN
Use edge functions
Optimize API responses
Monitor server performance
Regular optimization

Client-Side

Implement proper caching
Use service workers
Optimize rendering
Reduce reflows/repaints
Handle offline support
Monitor client performance
Regular optimization

Data Loading

Use proper fetching
Implement caching
Handle loading states
Optimize payload size
Use proper protocols
Monitor data loading
Regular optimization

Build Optimization

Optimize build process
Minimize asset size
Use proper compression
Implement caching
Monitor build metrics
Regular build audits
Document optimizations

Monitoring

Use performance monitoring
Track key metrics
Set up alerts
Monitor trends
Regular analysis
Document findings
Take action on insights

Documentation

Document performance goals
Track improvements
Document optimizations
Keep metrics history
Regular reviews
Share best practices
Maintain documentation

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.

yesterday First seen · 97 lines · 433 tokens per session scan A dd40b6105e71

Subscribe to this mod's changes

performance is a cursor rule published in the GitHub repository lacymorrow/paperclip-hub (15 stars, last pushed yesterday), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 433 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 2026-11-10.

CSS and styling Frontend ai-agents drizzle-orm nextjs paperclip payload-cms plugin-registry

performance next to 6 cursor rules from other repositories
Mod	Type	Stars	Last push	Licence	Scan	Tokens	Works with
performancelacymorrow/paperclip-hub	Cursor rule	15	yesterday	MIT	A	0	Cursor
codex-premium-website-skillsTheGoat395/Codex-Skills	Cursor rule	137	20d ago	MIT	A	0	Cursor
componentss0vers/next-app-i18n-starter	Cursor rule	66	4d ago	MIT	A	0	Cursor
always-push-pritsmemeworks/adhx	Cursor rule	19	5d ago	MIT	A	279	Cursor
ui-design-systemkrivoox/agent-stack-template	Cursor rule	30	1mo ago	MIT	A	0	Cursor
uiuseshape/Shape	Cursor rule	34	yesterday	none	A	0	Cursor
astro-development-guidelinesWebDevPeterGriffin/The-VibeCode-Bible	Cursor rule	42	7d ago	none	A	79	Cursor