Performance

Performance

Measures and improves loading, Core Web Vitals, images, fonts, JavaScript and animation cost on real devices.

What it does

Measures and improves loading, Core Web Vitals, images, fonts, JavaScript and animation cost on real devices.

When to use it

Use throughout implementation and before launch, whenever pages feel slow, shift, or block input.

Problems it prevents

Prevents a site that feels fast on a developer's laptop from being unusable on a mid-range phone.

Typical workflow

  1. Measure Core Web Vitals
  2. Audit images, fonts and JS weight
  3. Fix layout shift sources
  4. Re-measure on a real mobile device

Example output

A before/after Core Web Vitals comparison with the specific assets or scripts that were cut to get there.

What's included

  1. 01
    The complete prompt

    The full manual as a ready-to-save SKILL.md file, matched exactly to what ships in the T7 library.

  2. 02
    Install walkthrough

    Personal (~/.claude/skills/) and project (.claude/skills/) folder instructions, whichever fits how you work.

  3. 03
    Use notes

    How Claude invokes it, what a good result looks like, and what to check before you trust the output.

Installation

Save the manual as SKILL.md in ~/.claude/skills/performance/ to use it on every project, or in .claude/skills/performance/ to scope it to one repository. Then invoke it directly:

/performance

Read the official Claude Code skills guide

Works well with