performance-reviewer

performance-reviewer is a skill for Claude Code from majesticlabs-dev/majestic-marketplace. It costs 33 tokens per session (470 once invoked), scanned A, original, no licence file.

A review guide for finding performance problems in Rails code, including slow database queries and other bottlenecks. A bottleneck is a part of a system that limits its overall speed or capacity.

In plain words
What is it for?
Use it after implementing Rails features or when investigating slow queries, poor response times, or scalability concerns.
Why use it?
It helps identify what is making an application slow and points to areas that may need optimisation before the system must handle more work.

Skill for Claude Code

Written for Claude Code: allowed-tools in frontmatter.

Part of the majestic-rails plugin — 47 skills shipped together

Good fit Use it after implementing Rails features or when investigating slow queries, poor response times, or scalability concerns.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/majesticlabs-dev/majestic-marketplace/performance-reviewer
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 majesticlabs-dev/majestic-marketplace --skill performance-reviewer
Clone the repo
git clone --depth 1 https://github.com/majesticlabs-dev/majestic-marketplace

Made for: Claude Code.

Or install majestic-rails, the plugin that ships this one along with the rest of its 47 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-reviewer

README.md
[![agentmods](https://agentmods.dev/badge/skills/majesticlabs-dev/majestic-marketplace/performance-reviewer/github.svg)](https://agentmods.dev/skills/majesticlabs-dev/majestic-marketplace/performance-reviewer)
Your own site
<a href="https://agentmods.dev/skills/majesticlabs-dev/majestic-marketplace/performance-reviewer"><img src="https://agentmods.dev/badge/skills/majesticlabs-dev/majestic-marketplace/performance-reviewer/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-reviewer

Your own site · 80×15
<a href="https://agentmods.dev/skills/majesticlabs-dev/majestic-marketplace/performance-reviewer"><img src="https://agentmods.dev/badge/skills/majesticlabs-dev/majestic-marketplace/performance-reviewer.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 33 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 470 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.
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 $0.00033 $0.00470
Opus 5 $0.00016 $0.00235
Sonnet 5 $0.00007 $0.00094
Haiku 4.5 $0.00003 $0.00047

Measured yesterday against content hash 33535d55d1fa, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-12, from the pricing page.

Security

Grade A, and why

performance-reviewer 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 yesterday.

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.

plugins/majestic-rails/skills/performance-reviewer/SKILL.md · 65 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

Files

What ships with it

1 file beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

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. yesterday First seen · 65 lines · 33 tokens per session scan A 33535d55d1fa

Subscribe to this mod's changes

performance-reviewer is a skill published in the GitHub repository majesticlabs-dev/majestic-marketplace (50 stars, last pushed 2d ago), with no licence file. It adds 33 tokens to every session and 470 once invoked, about $0.0002 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 2026-09-11.

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