performance

performance is a skill for Claude Code, Cursor from millionco/react-doctor. It costs 53 tokens per session (977 once invoked), scanned A, original, no licence file.

A procedure for investigating slow React applications, using traces and evidence about rendering and user interactions.

In plain words
What is it for?
It is for diagnosing React runtime performance and comparing measured results before and after a change.
Why use it?
It helps identify unnecessary re-renders, slow interactions, and long browser tasks instead of relying on guesses.

Skill for Claude CodeCursor

Written for Claude Code and Cursor: disable-model-invocation in frontmatter, but also shipped in a Cursor plugin.

Part of the react-doctor plugin — 16 skills shipped together

Good fit It is for diagnosing React runtime performance and comparing measured results before and after a change.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/millionco/react-doctor/performance
Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Any agent
npx skills add millionco/react-doctor --skill performance
Clone the repo
git clone --depth 1 https://github.com/millionco/react-doctor

Made for: Claude Code, Cursor.

Or install react-doctor, the plugin that ships this one along with the rest of its 16 skills.

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

README.md
[![agentmods](https://agentmods.dev/badge/skills/millionco/react-doctor/performance/github.svg)](https://agentmods.dev/skills/millionco/react-doctor/performance)
Your own site
<a href="https://agentmods.dev/skills/millionco/react-doctor/performance"><img src="https://agentmods.dev/badge/skills/millionco/react-doctor/performance/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for performance

Your own site · 80×15
<a href="https://agentmods.dev/skills/millionco/react-doctor/performance"><img src="https://agentmods.dev/badge/skills/millionco/react-doctor/performance.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 53 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 977 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe. Third-party audits
  • NVIDIA SkillSpector warn 7 Sept 2026
SkillSpector: 1 finding, up to medium

These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →

  • medium MCP Rug Pull · line 37
    npx commands without a version suffix (e.g. @1.0.0) create a rug-pull risk if the upstream server is compromised and publishes a malicious update.
    Fix: Pin the version: npx @scope/[email protected]
How audits are shown
Origin unknown 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 $0.00053 $0.00977
Opus 5.5 $0.00021 $0.00391
Sonnet 5.5 $0.00011 $0.00195
Haiku 4.5 $0.00005 $0.00098

Measured 1mo ago against content hash d5a8e1dede20, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

performance 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 1mo 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.

skills/performance/SKILL.md · 114 lines

The source is not reproduced here

A licence we could not identify

The repository carries a LICENSE file, but it is custom or dual enough that GitHub cannot name it and neither can this catalogue. Unknown terms are not permission, so the body is not copied here. Read the licence at the source and decide for yourself.

Read it on GitHub

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. 1mo ago First seen · 114 lines · 53 tokens per session scan A d5a8e1dede20

Subscribe to this mod's changes

performance is a skill published in the GitHub repository millionco/react-doctor (15,048 stars, last pushed today), with no licence file. It adds 53 tokens to every session and 977 once invoked, about $0.0002 per session on Opus 5.5. 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 2026-08-30.

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