spa-performance SKILL.md skillA
spa-performance from leahycc/claude-skills is an agent skill: a SKILL.md folder an AI agent loads when a task calls for it.
mdr add leahycc/claude-skills/spa-performance@git:20261024.af7209aPins git:20261024.af7209a in mdr.lock. Pin the fingerprint instead.
- Audit grade
- A, 17 of 17 checks passed
- Kind
- SKILL.md skill
- Repository
- leahycc/claude-skills
- Path
skills/spa-performance/SKILL.md- Versions recorded
- 3
- Latest version
- git:20261024.af7209a, committed Oct 24, 2026
- First version recorded
- Oct 22, 2026
- Size
- 4,433 bytes
- Repository stars
- 3
- License
- MIT
Use when an SPA is slow because of the main thread, frame time, or memory: Web Workers, OffscreenCanvas, scheduler.yield, virtualized or windowed rendering, canvas and DOM editors, image swaps, flicker, blank frames, live updates, or a performance harness. Not React re-renders, bundles, or Server Components (see react-performance).
Collected from public GitHub. Every version is saved exactly as it was and never changes. Install it at an exact version with the mdr tool, and every file is checked before it reaches your agent. The main file is checked against the SHA-256 fingerprint recorded here, and the others against the fingerprints GitHub keeps for its source commit. The automatic checks below grade the latest version, and the same checks always give the same file the same grade.
What the file says
# SPA performance
Browser performance for a single-page app: what runs on the main thread, what is worth drawing, and how to prove a change helped. Framework rendering, bundle size, and Server Components belong to the `react-performance` skill.
**Measure the moment the user feels, then change one thing.** A faster load that stalls the gesture is a loss. Measure that change alone and again with the rest of the system. Thresholds, the harness, and the worked example live in [measure.md](./resources/measure.md).
Source checks and what is still open: [SOURCES.md](SOURCES.md).
## Procedure
1. Name the moment: first paint of a thing, a gesture (pan, scroll, drag), a keystroke, or a tick of live data.
2. Read the one resource for that moment before choosing a technique. If its first line says `Status: open` or `Status: partial`, apply the written rules and do not invent the items under its Fill in list.
3. Record a baseline with the harness in [measure.md](./resources/measure.md). DevTools finds the cause. The quoted number comes from a rerun with DevTools closed.
4. Classify the cost and change the smallest thing that attacks it.
```
name the moment
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v
…Read the whole file at its exact version.
How to install
mdr add leahycc/claude-skills/spa-performance@sha256:9a4be9f80207044fThe line at the top of this page pins the label git:20261024.af7209a, which is what most people want. This one pins the sha256 fingerprint of the contents instead, so it survives a label being moved. Either way the exact version is written to mdr.lock, and mdr install downloads and checks those contents again, so it installs them exactly or stops with an error.
[](https://markdownregistry.com/a/art_2eyjdyxnrhstafcg)
2 badge image fetches in 30 days. What the badge shows.
Versions
The registry has recorded 3 versions of this file, between Oct 22, 2026 and Oct 24, 2026, more than one a day.
| version | committed | commit | size | audit | |
|---|---|---|---|---|---|
| git:20261024.af7209a latest | 2026-10-24 | af7209a | 4,433 B | A | view · diff |
| git:20261023.9ecc8c1 | 2026-10-23 | 9ecc8c1 | 4,124 B | A | view · diff |
| git:20261022.a666eab | 2026-10-22 | a666eab | 4,405 B | A | view |
Audit of the latest version
- pass: Frontmatter block present
- pass: Frontmatter declares a name
- pass: Frontmatter declares a description
- pass: Size between 200 bytes and 200 KB (4433 bytes)
- pass: No zero-width or bidi control characters
- pass: No instruction hidden inside an HTML comment
- pass: No link to an exfiltration or paste host
- pass: No credential-shaped string
- pass: No instruction to send local credentials anywhere
- pass: No text hidden with inline styles
- pass: No prompt-injection phrasing
- pass: No curl or wget piped into a shell
- pass: No recursive delete of root, home or parent
- pass: No instruction to read or print local credentials
- pass: No base64 blob over 200 characters
- pass: No link to a raw IP address
- pass: No script tag
Source
leahycc/claude-skills · 3 stars · license MIT · pushed 2026-11-02 · branch main
API
GET https://markdownregistry.com/api/v1/artifacts/art_2eyjdyxnrhstafcg GET https://markdownregistry.com/api/v1/resolve?ref=leahycc/claude-skills/spa-performance GET https://markdownregistry.com/api/v1/blob/9a4be9f80207044faa3c6695bd421b216048063eb794b9d455094c969835813b
Your AI assistant does the legwork. You hear about the deals worth your word. Hand yours the standing instructions at modelranch.com and it joins the network that reads files like this one.
Guides: the SKILL.md format and its required fields · what to check before you install a skill · how to pin a skill to an exact version · where to find agent skills · keeping a team on the same skills · which agent file does what.