html5-game-editor: Skill for Cursor

.cursor/skills/performance-audit/SKILL.md

performance-audit is a skill for Cursor from andvolodko/html5-game-editor. It costs 60 tokens per session (1,526 once invoked), scanned A, original, MIT.

A measurement-first guide for finding performance problems in code editors, game previews, and running games.

In plain words
What is it for?
Use it to reproduce jank, measure frame time and FPS, inspect draw calls and allocations, and fix costly scene or rendering work.
Why use it?
It replaces guesses about slow code with a measured baseline, so changes target the part causing frame drops, memory growth, rerendering, or excessive drawing.

Skill for Cursor

Written for Cursor: installed under .cursor/.

This is andvolodko/html5-game-editor's own configuration. It tells Cursor how to work on html5-game-editor itself, so it is not a mod to install elsewhere. Copy it as a starting point and replace the rules that are about this project. Everything html5-game-editor configures →

Reuse

Borrowing it

Nothing to install: this file belongs to andvolodko/html5-game-editor. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file
curl -O https://raw.githubusercontent.com/andvolodko/html5-game-editor/master/.cursor/skills/performance-audit/SKILL.md
Clone the repo
git clone --depth 1 https://github.com/andvolodko/html5-game-editor

Made for: Cursor.

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-audit

README.md
[![agentmods](https://agentmods.dev/badge/skills/andvolodko/html5-game-editor/performance-audit.svg)](https://agentmods.dev/skills/andvolodko/html5-game-editor/performance-audit)
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<a href="https://agentmods.dev/skills/andvolodko/html5-game-editor/performance-audit"><img src="https://agentmods.dev/badge/skills/andvolodko/html5-game-editor/performance-audit.svg" alt="Measured on agentmods" height="20"></a>
Per session 60 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,526 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
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 $0.00060 $0.01526
Opus 5 $0.00030 $0.00763
Sonnet 5 $0.00012 $0.00305
Haiku 4.5 $0.00006 $0.00153

Measured 6d ago against content hash 55f7563c346e, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-06, from the pricing page.

Security

Grade A, and why

performance-audit 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 6d 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.

.cursor/skills/performance-audit/SKILL.md · 127 lines

How it starts

The opening of the file, as written. The whole thing — 127 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Performance Audit

Measurement-first workflow. Do not change architecture on a hunch.

Architecture constraints: docs/architecture.md (Performance) and .cursor/rules/core.mdc. Editor viewport rules: .cursor/rules/editor-ui.mdc.

When to use this skill

  • Editor Scene/Preview jank, hitching, or memory growth.
  • Game runtime FPS drops, GC spikes, or high Performance Meter stats.
  • A change is suspected of rebuilding the whole scene graph or re-rendering React every ticker frame.
  • User asks to “optimize” without a measured hot path.

Do not use this to sprinkle caches through unrelated modules.

Before changing code

  1. Reproduce the slow case with a concrete scene (demo games/editor-features-demo/assets/scenes/perfomance-test.json exists for load; also hybrid.json / world3d.json / Spine scenes).
  2. Identify the hot path (editor viewport vs Preview/GameRuntime vs Asset Browser vs Inspector).
  3. Establish a baseline (FPS, frame time, draw calls, display object counts, allocations). Guessing is not a baseline.
  4. Read the existing sync model: EditorViewportController is incremental; SceneRenderer.clear is load/recovery only (packages/scene/src/scene-renderer.ts).

This repo does not use Zustand. Editor UI subscribes via useEditorStateeditor.getStoreVersion() (apps/editor/src/hooks/useEditorState.ts).

Audit workflow

reproduce
→ identify hot path
→ establish baseline
→ inspect architecture
→ implement smallest safe optimization
→ verify behavior
→ compare before/after
→ add regression test where practical

1. Reproduce and classify

Surface Typical cost
Editor Scene Pixi/Three update + gizmos + selection chrome
Preview / game GameRuntime.tick → scripts updaterenderer.render
React shell editor.subscribe notifying every panel
Assets import, thumbnail decode, preview hosts
Persistence JSON.stringify of the whole scene (save, not per frame)

Read the full file on GitHub · 127 lines

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. 6d ago First seen · 127 lines · 60 tokens per session scan A 55f7563c346e

Subscribe to this mod's changes

performance-audit is a skill published in the GitHub repository andvolodko/html5-game-editor (6 stars, last pushed 11d ago), licensed MIT. It adds 60 tokens to every session and 1,526 once invoked, about $0.0003 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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