review-performance

review-performance is a skill for Claude Code, Codex from dhaupin/vant. It costs 7 tokens per session (490 once invoked), scanned A, original, MIT.

A checklist for measuring and reviewing how quickly an application runs. It covers response times, downloaded data, database queries, and asynchronous tasks.

In plain words
What is it for?
Use it to inspect APIs, pages, builds, network transfers, database access, and background tasks, then record issues and suggested fixes.
Why use it?
It helps identify slow parts using measurements rather than guesses, including repeated database queries and tasks that run one after another.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Good fit Use it to inspect APIs, pages, builds, network transfers, database access, and background tasks, then record issues and suggested fixes.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/dhaupin/vant/vant-skill-review-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 dhaupin/vant --skill vant-skill-review-performance
Clone the repo
git clone --depth 1 https://github.com/dhaupin/vant

Made for: Claude Code, Codex.

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 review-performance

README.md
[![agentmods](https://agentmods.dev/badge/skills/dhaupin/vant/vant-skill-review-performance.svg)](https://agentmods.dev/skills/dhaupin/vant/vant-skill-review-performance)
Your own site
<a href="https://agentmods.dev/skills/dhaupin/vant/vant-skill-review-performance"><img src="https://agentmods.dev/badge/skills/dhaupin/vant/vant-skill-review-performance.svg" alt="Measured on agentmods" height="20"></a>
Per session 7 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 490 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 1 finding. A grade says what 26 rules found in the file — not that it is safe.
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 $0.00007 $0.00490
Opus 5 $0.00003 $0.00245
Sonnet 5 $0.00001 $0.00098
Haiku 4.5 $0.00001 $0.00049

Measured 8d ago against content hash f3d8584df684, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-08, from the pricing page.

Security

Grade A, and why

review-performance scanned grade A with 1 finding 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 8d 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.

Makes network callslowCapability

Not a fault in itself. Listed so you know the mod talks to something, and to what.

curl -s -o /dev/null -w "%{size_download}" URL
models/public/skills/vant-skill-review-performance/SKILL.md · 124 lines

What it actually says

Performance Review

Is it fast?


Rule #1

Measure. Don't guess.

# Profile before you optimize
node --prof app.js

What To Check

1. Time

// Time operations
const start = Date.now()
doThing()
console.log(Date.now() - start)
Check Target
API < 200ms
Page < 1s
Build < 30s

2. Network

# Check size
curl -s -o /dev/null -w "%{size_download}" URL
Size Rating
> 1MB SLOW
> 500KB MEDIUM
< 100KB FAST

3. Queries

// N+1 query?
items.map(i => db.get(i.id))
Pattern Issue Fix
query in loop N+1 Batch
select * Too much Select needed
no cache Repeat Cache

4. Async

// Blocking?
await heavy()
await more()
Pattern Issue Fix
Sequential Slow Promise.all
No timeout Hang Timeout
No limit OOM Limit

Output

## Performance - [endpoint]

### Timing
- [TIME] [endpoint]: [ms]ms
- Target: [target]ms

### Network
- [SIZE] [kb]kb

### Queries
- [COUNT] queries for [records]
- Issue: [pattern]

### Recommendations
1. [fix 1]
2. [fix 2]

Fix Priority

Priority When
1 Blocks user
2 Noticeable delay
3 Optimization

Role: Performance Reviewer
Input: Code or endpoint
Output: Is fast?

Measure it. Fix what matters.

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. 8d ago First seen · 124 lines · 7 tokens per session scan A f3d8584df684

Subscribe to this mod's changes

review-performance is a skill published in the GitHub repository dhaupin/vant (9 stars, last pushed 8d ago), licensed MIT. It adds 7 tokens to every session and 490 once invoked, about $0.0000 per session on Opus 5. A static security scan graded it A with 1 finding (makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.

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