Code Review Checklist
shareAI-lab/learn-claude-code
Reviews code against a five-part checklist covering security, correctness, performance, maintainability and testing, and reports findings in a fixed format.
Measure-first performance optimization that balances gains against complexity.
Install Optimizing Performance
$ npx skills add rileyhilliard/claude-essentials --skill optimizing-performance -a claude-codeProject install by default; add -g for ~/.claude/skills/.
$ gh skill install rileyhilliard/claude-essentials optimizing-performance --agent claude-codeProject scope by default; add --scope user for a personal install. Needs GitHub CLI 2.90.0 or later (public preview).
$ git clone --depth 1 https://github.com/rileyhilliard/claude-essentials.git skills-src && mkdir -p .claude/skills && cp -r skills-src/plugins/ce/skills/optimizing-performance .claude/skills/optimizing-performance && rm -rf skills-srcUse ~/.claude/skills/ instead of .claude/skills for a personal install. The folder must contain SKILL.md.
Claude Code skills documentation · loads skills from .claude/skills/
Install the "optimizing-performance" agent skill from https://github.com/rileyhilliard/claude-essentials/tree/main/plugins/ce/skills/optimizing-performance into .claude/skills/optimizing-performance/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "optimizing-performance", then confirm the skill loads.Claude Code copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$skill-installer install https://github.com/rileyhilliard/claude-essentials/tree/main/plugins/ce/skills/optimizing-performanceType this inside Codex. $skill-installer <name> installs a curated skill from openai/skills. The installer writes to $CODEX_HOME/skills (default ~/.codex/skills). Restart Codex if the skill does not show up.
$ npx skills add rileyhilliard/claude-essentials --skill optimizing-performance -a codexProject install goes to .agents/skills/; add -g for ~/.codex/skills/.
$ gh skill install rileyhilliard/claude-essentials optimizing-performance --agent codexProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/rileyhilliard/claude-essentials.git skills-src && mkdir -p .agents/skills && cp -r skills-src/plugins/ce/skills/optimizing-performance .agents/skills/optimizing-performance && rm -rf skills-srcUse ~/.agents/skills/ instead of .agents/skills for a personal install.
Codex skills documentation · loads skills from .agents/skills/
Install the "optimizing-performance" agent skill from https://github.com/rileyhilliard/claude-essentials/tree/main/plugins/ce/skills/optimizing-performance into .agents/skills/optimizing-performance/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "optimizing-performance", then confirm the skill loads.Codex copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ npx skills add rileyhilliard/claude-essentials --skill optimizing-performance -a cursorProject install goes to .agents/skills/; add -g for ~/.cursor/skills/.
$ gh skill install rileyhilliard/claude-essentials optimizing-performance --agent cursorProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/rileyhilliard/claude-essentials.git skills-src && mkdir -p .cursor/skills && cp -r skills-src/plugins/ce/skills/optimizing-performance .cursor/skills/optimizing-performance && rm -rf skills-srcUse ~/.cursor/skills/ instead of .cursor/skills for a personal install.
Cursor skills documentation · loads skills from .cursor/skills/, .agents/skills/, .claude/skills/, .codex/skills/
Install the "optimizing-performance" agent skill from https://github.com/rileyhilliard/claude-essentials/tree/main/plugins/ce/skills/optimizing-performance into .cursor/skills/optimizing-performance/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "optimizing-performance", then confirm the skill loads.Cursor copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ gemini skills install https://github.com/rileyhilliard/claude-essentials.git --path plugins/ce/skills/optimizing-performance--scope user (default) or --scope workspace; --path is the subfolder of the repo that holds the skill; --consent skips the security confirmation prompt.
$ npx skills add rileyhilliard/claude-essentials --skill optimizing-performance -a gemini-cliProject install goes to .agents/skills/; add -g for ~/.gemini/skills/.
$ gh skill install rileyhilliard/claude-essentials optimizing-performance --agent gemini-cliProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/rileyhilliard/claude-essentials.git skills-src && mkdir -p .gemini/skills && cp -r skills-src/plugins/ce/skills/optimizing-performance .gemini/skills/optimizing-performance && rm -rf skills-srcUse ~/.gemini/skills/ instead of .gemini/skills for a personal install, then run /skills reload.
Gemini CLI skills documentation · loads skills from .gemini/skills/, .agents/skills/
Install the "optimizing-performance" agent skill from https://github.com/rileyhilliard/claude-essentials/tree/main/plugins/ce/skills/optimizing-performance into .gemini/skills/optimizing-performance/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "optimizing-performance", then confirm the skill loads.Gemini CLI copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ gh skill install rileyhilliard/claude-essentials optimizing-performanceInstalls for Copilot at project scope by default; add --scope user for a personal install. Preview a skill first with gh skill preview. Needs GitHub CLI 2.90.0 or later (public preview).
$ npx skills add rileyhilliard/claude-essentials --skill optimizing-performance -a github-copilotProject install goes to .agents/skills/; add -g for ~/.copilot/skills/.
$ git clone --depth 1 https://github.com/rileyhilliard/claude-essentials.git skills-src && mkdir -p .github/skills && cp -r skills-src/plugins/ce/skills/optimizing-performance .github/skills/optimizing-performance && rm -rf skills-srcUse ~/.copilot/skills/ instead of .github/skills for a personal install. Commit .github/skills so cloud agent and code review can use it.
GitHub Copilot skills documentation · loads skills from .github/skills/, .claude/skills/, .agents/skills/
Install the "optimizing-performance" agent skill from https://github.com/rileyhilliard/claude-essentials/tree/main/plugins/ce/skills/optimizing-performance into .github/skills/optimizing-performance/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "optimizing-performance", then confirm the skill loads.GitHub Copilot copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ npx skills add rileyhilliard/claude-essentials --skill optimizing-performance -a opencodeOpenCode documents no install command of its own. Project install goes to .agents/skills/; add -g for ~/.config/opencode/skills/.
$ gh skill install rileyhilliard/claude-essentials optimizing-performance --agent opencodeProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/rileyhilliard/claude-essentials.git skills-src && mkdir -p .opencode/skills && cp -r skills-src/plugins/ce/skills/optimizing-performance .opencode/skills/optimizing-performance && rm -rf skills-srcUse ~/.config/opencode/skills/ instead of .opencode/skills for a personal install.
OpenCode skills documentation · loads skills from .opencode/skills/, .claude/skills/, .agents/skills/
Install the "optimizing-performance" agent skill from https://github.com/rileyhilliard/claude-essentials/tree/main/plugins/ce/skills/optimizing-performance into .opencode/skills/optimizing-performance/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "optimizing-performance", then confirm the skill loads.OpenCode copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
Facts
- Skill name
optimizing-performance- GitHub stars
- 130
- Token cost
- ~470 tokens
- SKILL.md length
- 113 words
- Files
- 1
- Skills in repo
- 17
- Repo updated
- First seen
- Licence
- MIT
At a glance
Measure-first performance optimization that balances gains against complexity.
- Addressing slow code
- SKILL.md covers The Golden Rule, Win-Win Optimizations (Always…, High-Value Optimizations and Red Flags
- Calls git
- Profiling issues
What it does
Optimizing Performance is an agent skill from rileyhilliard/claude-essentials. Measure-first performance optimization that balances gains against complexity. Use when addressing slow code, profiling issues, or evaluating optimization trade-offs.
Its SKILL.md is about 470 tokens, which your agent loads only when the skill is triggered. It is a single SKILL.md file with no bundled scripts.
It sits in Development, covering Performance optimization. The licence is MIT.
When your agent uses it
- Addressing slow code
- Profiling issues
- Evaluating optimization trade-offs
Example prompts
- “/optimizing-performance”
What it can do on your machine
Read from SKILL.md and the folder at commit 3a67a01. It shows what the files ask for, not the result of running them.
Tool permissions
Pre-approves nothing: there is no allowed-tools line, so your agent's usual permission prompts apply.
From allowed-tools in the SKILL.md frontmatter.
Runs code
Shell commands in SKILL.md call:
git
From the folder's file list and the shell code blocks in SKILL.md.
Network
No URLs in SKILL.md. Its commands use git, which can reach the network depending on how they are called.
From URLs in SKILL.md, links to its own repository left out.
Credentials
Names no API keys, tokens, secrets or passwords.
From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.
Context cost
Optimizing Performance loads about 470 tokens when it runs. Until then it costs about 47 tokens; SKILL.md has 113 words of instructions outside code blocks.
Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.
Safety
Auto-check passed
The automated check found no risky patterns in SKILL.md.
Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); files beside SKILL.md are not scanned.
SKILL.md
The full file from rileyhilliard/claude-essentials at commit 3a67a01, republished under its MIT licence (© rileyhilliard). 113 words, ~470 tokens.
Download SKILL.mdSave it as
.claude/skills/optimizing-performance/SKILL.md (or your agent's skills folder).- name
- optimizing-performance
- description
- Measure-first performance optimization that balances gains against complexity. Use when addressing slow code, profiling issues, or evaluating optimization trade-offs.
Optimizing Performance
Core principle: Readable code that's "fast enough" beats complex code that's "optimal". Measure first.
Focus area: Use an explicitly named target if one was given. Otherwise, run git diff and focus on unstaged changes. If no unstaged changes exist, ask the user what to optimize.
The Golden Rule
IF optimization reduces complexity AND improves performance → ALWAYS DO IT
IF optimization increases complexity → Only if 10x faster OR fixes critical UX (>16ms UI, >100ms input)Win-Win Optimizations (Always Do)
Multiple loops → Single loop:
// ❌ Three passes
const ids = users.map(u => u.id);
const active = users.filter(u => u.active);
// ✅ One pass
const { ids, active } = users.reduce((acc, u) => {
acc.ids.push(u.id);
if (u.active) acc.active.push(u);
return acc;
}, { ids: [], active: [] });Nested loops → Hash map (O(n²) → O(n)):
// ❌ O(n²)
const matched = orders.filter(o => users.some(u => u.id === o.userId));
// ✅ O(n)
const userIds = new Set(users.map(u => u.id));
const matched = orders.filter(o => userIds.has(o.userId));High-Value Optimizations
| Pattern | When | Fix |
|---|---|---|
| Virtualization | Lists >1000 items | react-window, tanstack-virtual |
| Memoization | >5ms calc OR unnecessary re-renders | useMemo, React.memo |
| Batching | Multiple state updates | Single setState, bulk INSERT |
| Lazy loading | Large dependencies | import('./heavy-lib') |
Red Flags
- Optimizing without benchmark data
- Micro-optimizing <16ms code
- Adding complexity for minimal gain
- Optimizing infrequently-run code
© rileyhilliard, MIT. Rendered from Markdown: HTML in the file is shown as text, images as links, and headings moved down two levels. Raw file
Files
Just SKILL.md in plugins/ce/skills/optimizing-performance of rileyhilliard/claude-essentials.
Open the folder on GitHubat commit 3a67a01
Compare with similar skills
Optimizing Performance next to the 5 skills that share the most tags, products or categories with it. Stars are the repository's; “used in” counts other GitHub owners with a copy.
| Skill | Stars | Used in | Tokens | Auto-check | Licence | Repo updated |
|---|---|---|---|---|---|---|
| Optimizing Performance this skillrileyhilliard/claude-essentials | 130 | — | ~470 | Automated safety check: Pass | MIT | |
| Code Review ChecklistshareAI-lab/learn-claude-code | 78k | 5 repos | ~1.1k | Automated safety check: Pass | MIT | |
| LLM Torch Profiler Analysissgl-project/sglang | 37k | 2 repos | ~6.4k | Automated safety check: Pass | Apache-2.0 | |
| Pycrazyguitar/pysheeet | 8.2k | — | ~886 | Automated safety check: Pass | MIT | |
| Cmux Debugging Guidemanaflow-ai/cmux | 28k | 1 repos | ~1.1k | Automated safety check: Pass | Custom licence | |
| Electron Heap Snapshot Analysiskeybase/client | 9.3k | — | ~875 | Automated safety check: Pass | BSD-3-Clause |
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Related
Categories
Questions about Optimizing Performance
What does Optimizing Performance do?
Measure-first performance optimization that balances gains against complexity. Optimizing Performance is an agent skill from rileyhilliard/claude-essentials. Measure-first performance optimization that balances gains against complexity.
When should I use Optimizing Performance?
Optimizing Performance fits situations like: addressing slow code; profiling issues; evaluating optimization trade-offs.
How do I install Optimizing Performance in Claude Code?
Run `npx skills add rileyhilliard/claude-essentials --skill optimizing-performance -a claude-code`. Or copy the skill folder (plugins/ce/skills/optimizing-performance in rileyhilliard/claude-essentials) into .claude/skills/optimizing-performance in your project. Claude Code loads it when a task matches its description.
How do I install Optimizing Performance in Codex?
Run `npx skills add rileyhilliard/claude-essentials --skill optimizing-performance -a codex`. Or copy the skill folder (plugins/ce/skills/optimizing-performance in rileyhilliard/claude-essentials) into .agents/skills/optimizing-performance in your project. Codex loads it when a task matches its description.
Can I use Optimizing Performance in Cursor, Gemini CLI or GitHub Copilot?
Cursor, Gemini CLI, GitHub Copilot and OpenCode also load SKILL.md folders. With the skills CLI, run `npx skills add rileyhilliard/claude-essentials --skill optimizing-performance -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/optimizing-performance, .gemini/skills/optimizing-performance, .github/skills/optimizing-performance and .opencode/skills/optimizing-performance in your project.
What does Optimizing Performance need to run?
Going by SKILL.md and its folder, Optimizing Performance needs the command-line tools its instructions call (git).
Does Optimizing Performance access the network?
SKILL.md contains no URLs. Its commands use git, which can reach the network depending on how they are called. This is read from the text; nothing was executed.
Is Optimizing Performance safe to install?
Our automated static check of SKILL.md found no risky patterns, such as piping downloads into a shell, reading credential files or hidden Unicode. It is not a guarantee. Review the folder before installing.
What licence does Optimizing Performance use?
Optimizing Performance is published under the MIT licence (the repository's licence). It allows redistribution, so the full SKILL.md is shown on this page.
How many tokens does Optimizing Performance use?
About 470 tokens (SKILL.md is roughly 1.9k characters). Agents keep only the skill's name and description in context until a task matches; then they load SKILL.md in full.
What are the alternatives to Optimizing Performance?
Skills that share tags, products or a category with Optimizing Performance: Code Review Checklist (shareAI-lab/learn-claude-code, 78k stars), LLM Torch Profiler Analysis (sgl-project/sglang, 37k stars), Py (crazyguitar/pysheeet, 8.2k stars) and Cmux Debugging Guide (manaflow-ai/cmux, 28k stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.
Who maintains Optimizing Performance?
rileyhilliard (a GitHub user) maintains it in rileyhilliard/claude-essentials, which has 130 GitHub stars. The repository holds 17 skills in this directory. The repository was last updated on August 18, 2026.
Source: rileyhilliard/claude-essentials on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.