Speed tuner
Name what feels slow. Get the real bottleneck measured, fixed and measured again.
Speed tuner is a free AI skill for the job "Test and fix code". Give the instructions to an AI assistant that supports the required files and tools, then review its output.
Free · No account · MIT licence · Made by Addy Osmani · Level: advanced · Thinking: high
Made by Addy Osmani. See the original on GitHub; we copied it as it is, with its licence.
What it does
A slow page or feature measured, fixed at the real bottleneck, then measured again to prove the gain. The skill refuses to guess. It sets a baseline first, using Lighthouse or browser tools for repeatable tests and real user data for what people actually feel. Then it finds the true cause. For the front end it checks Core Web Vitals: largest paint under 2.5 seconds, interaction delay under 200 ms and layout shift under 0.1. For the back end it hunts for repeated database queries and slow calls. It applies one fix, verifies the result, and adds a guard so it does not slip back.
You give it
- What feels slow and where
- The code or page involved
- Current timings or a Lighthouse report (optional)
You get
- A measured baseline
- The real bottleneck, named
- A targeted fix
- Before and after numbers
- A check to stop the slowdown returning
Use it when
- Users say your site or app feels slow.
- Your Core Web Vitals scores are in the red.
- A recent change made things slower and you do not know which.
- A page struggles with big data sets or heavy traffic.
How to use it
- Add it to your AI once: download it and add the folder to Claude, ChatGPT or Codex as a skill.
- Ask for the job in your own words. Your AI opens the skill when it fits.
- It works best when your AI can run code and read your project files.