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.
npx agentmods add rules/kok-o/koko-contextos-agents/performancegit clone --depth 1 https://github.com/kok-o/koko-contextos-agentsWhat 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 | $0.00005 | $0.00942 |
| Opus 5 | $0.00003 | $0.00471 |
| Sonnet 5 | $0.00001 | $0.00188 |
| Haiku 4.5 | $0.00001 | $0.00094 |
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 2d ago.
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.
How it starts
The opening of the file, as written. The whole thing — 79 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Skill: Web Performance
Web Performance & Core Web Vitals
Overview
Enforces high-efficiency frontend and full-stack performance standards to achieve exceptional Core Web Vitals: Largest Contentful Paint (LCP < 2.5s), Interaction to Next Paint (INP < 200ms), and Cumulative Layout Shift (CLS < 0.1).
When to Use
Activate whenever analyzing, profiling, writing, or optimizing page loading speeds, network waterfalls, script bundling, animation frame rates, or data caching.
Negative Constraints (What NOT to Do)
- NEVER introduce async waterfalls: Do not chain sequential
awaitcalls when requests can be executed concurrently viaPromise.all(). - NEVER import large full libraries when only a utility is needed: Never
import _ from 'lodash'; useimport debounce from 'lodash/debounce'or native alternatives. - NEVER render images or videos without explicit aspect ratios: Always provide
widthandheightoraspect-ratioto avoid Cumulative Layout Shift (CLS). - NEVER trigger synchronous layout thrashing: Do not alternate between reading layout properties (
offsetHeight,getBoundingClientRect) and writing styles in loops. - NEVER animate non-composited properties: Animate only GPU-composited CSS properties (
transform,opacity). Never animatewidth,height,top,left, ormargin.
Rules & Patterns
1. Vercel Optimization Hierarchy by Impact
| Priority | Category | Key Optimization Target | Expected Impact |
|---|---|---|---|
| 1. CRITICAL | Eliminating Waterfalls | Parallel data fetching (Promise.all), Suspense streaming |
30–60% faster LCP |
| 2. CRITICAL | Bundle Size Optimization | Direct submodule imports, next/dynamic, deferring 3rd party scripts |
40–70% smaller initial JS |
| 3. HIGH | Server-Side & RSC Caching | React.cache() request deduplication, edge SSR caching |
Lower TTFB & DB load |
| 4. MEDIUM-HIGH | Client Query Optimization | SWR / TanStack Query stale-while-revalidate, deduplication | Zero redundant network calls |
| 5. MEDIUM | Render & DOM Optimization | Virtualization for large lists, state colocation, :focus-visible |
Smooth 60 FPS / INP < 100ms |
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.
- 2d ago First seen · 79 lines · 5 tokens per session scan A c3c139547bcd
performance is a cursor rule published in the GitHub repository kok-o/koko-contextos-agents (2 stars, last pushed 2d ago), licensed MIT. It adds 5 tokens to every session and 942 once invoked, about $0.0000 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 2026-08-31.
Other cursor rules, from other repositories
clean-code
Apply language-agnostic clean-code discipline to all code writing, editing, reviewing, testing, and refactoring, including file placement, single responsibility, and verified completion.
unity-performance
Cursor rule "unity-performance" from Common-ka/ai-agent-unity-rules, covering unity performance rules, update/fixedupdate/lateupdate, usage rules, object pooling (unityengine.pool) and addressables (not resources).
react-composition-patterns
React composition patterns for scalable component architecture including compound components, context providers, state management, boolean prop alternatives, render props vs children, and React 19 API changes. Use when refactoring components with many boolean props, building component libraries, designing flexible…
react-advanced-patterns
Advanced React patterns for refs, stable callbacks, useEffectEvent, and application initialization. Use when dealing with event handler refs, stable callback references, subscription management, effect dependencies, or one-time app initialization.
general-typescript-rule
Applies general TypeScript best practices and style guidelines to all TypeScript files in the project.
readme-best-practices
README Best Practices - enforces high-quality README patterns when creating or editing README files.