performance-tuner

performance-tuner is a skill for Claude Code, Codex from FutureJJ/claude-skills. It costs 49 tokens per session (196 once invoked), scanned A, original, MIT.

A guide to finding and fixing slow software, including how to measure performance, reuse results with caching, load content later, configure CDNs, and improve Core Web Vitals, Google's page-speed user experience measures.

In plain words
What is it for?
Use it to investigate slow applications, improve page loading, choose caching approaches, configure a CDN, and reduce API response times.
Why use it?
It helps identify the actual cause of slow pages or APIs before making changes, while accounting for reliability and maintenance.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Good fit Use it to investigate slow applications, improve page loading, choose caching approaches, configure a CDN, and reduce API response times.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/futurejj/claude-skills/performance-tuner
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 FutureJJ/claude-skills --skill performance-tuner
Clone the repo
git clone --depth 1 https://github.com/FutureJJ/claude-skills

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.

agentmods badge for performance-tuner

README.md
[![agentmods](https://agentmods.dev/badge/skills/futurejj/claude-skills/performance-tuner.svg)](https://agentmods.dev/skills/futurejj/claude-skills/performance-tuner)
Your own site
<a href="https://agentmods.dev/skills/futurejj/claude-skills/performance-tuner"><img src="https://agentmods.dev/badge/skills/futurejj/claude-skills/performance-tuner.svg" alt="Measured on agentmods" height="20"></a>
Per session 49 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 196 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.

ModelPer sessionOnce invoked
Fable 5.1 $0.00049 $0.00196
Opus 5 $0.00024 $0.00098
Sonnet 5 $0.00010 $0.00039
Haiku 4.5 $0.00005 $0.00020

Measured 8d ago against content hash 909667d7661d, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-08, from the pricing page.

Security

Grade A, and why

performance-tuner 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 8d 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.

skills/performance-tuner/SKILL.md · 29 lines

What it actually says

Performance Tuner

You are an expert in performance tuner focused on production-grade solutions.

Core Principles

  • Follow industry best practices and proven patterns
  • Optimize for maintainability and reliability
  • Document decisions and trade-offs
  • Measure before optimizing

Anti-Patterns

  • Over-engineering simple solutions
  • Ignoring error handling and edge cases
  • Copying patterns without understanding context
  • Premature optimization without profiling

Reference Guide

Topic Reference Load When
Core patterns references/patterns.md Common patterns and best practices
Advanced topics references/advanced.md Complex scenarios and optimization
Files

What ships with it

2 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.

  1. 8d ago First seen · 29 lines · 49 tokens per session scan A 909667d7661d

Subscribe to this mod's changes

performance-tuner is a skill published in the GitHub repository FutureJJ/claude-skills (3 stars, last pushed 6mo ago), licensed MIT. It adds 49 tokens to every session and 196 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 2026-08-31.

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