ios-perceived-performance

ios-perceived-performance is a skill for Claude Code, Codex from Livsy90/iOS-Performance-Agent-Skills. It costs 89 tokens per session (2,025 once invoked), scanned A, original, MIT.

An iOS review skill for how responsive an app feels while screens load or actions finish. It examines visible feedback such as loading states, placeholders, progressive content, optimistic updates, retries, and rollbacks.

In plain words
What is it for?
Use it to review loading and refresh flows, prevent duplicate taps or submissions, handle high-stakes actions safely, and validate responsiveness with tests, recordings, Instruments, MetricKit, or production signals.
Why use it?
It helps explain why an app feels slow, blank, jumpy, or stuck even when the underlying operation is not unusually slow.

Skill for Claude CodeCodex

Written for Claude Code and Codex: shipped in a Claude Code plugin, but also agents/openai.yaml present.

Part of the iOS-Performance-Agent-Skills plugin — 6 skills shipped together

Good fit Use it to review loading and refresh flows, prevent duplicate taps or submissions, handle high-stakes actions safely, and validate responsiveness with tests, recordings, Instruments, MetricKit, or production signals.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/livsy90/ios-performance-agent-skills/ios-perceived-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 Livsy90/iOS-Performance-Agent-Skills --skill ios-perceived-performance
Clone the repo
git clone --depth 1 https://github.com/Livsy90/iOS-Performance-Agent-Skills

Made for: Claude Code, Codex.

Or install iOS-Performance-Agent-Skills, the plugin that ships this one along with the rest of its 6 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 ios-perceived-performance

README.md
[![agentmods](https://agentmods.dev/badge/skills/livsy90/ios-performance-agent-skills/ios-perceived-performance/github.svg)](https://agentmods.dev/skills/livsy90/ios-performance-agent-skills/ios-perceived-performance)
Your own site
<a href="https://agentmods.dev/skills/livsy90/ios-performance-agent-skills/ios-perceived-performance"><img src="https://agentmods.dev/badge/skills/livsy90/ios-performance-agent-skills/ios-perceived-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 ios-perceived-performance

Your own site · 80×15
<a href="https://agentmods.dev/skills/livsy90/ios-performance-agent-skills/ios-perceived-performance"><img src="https://agentmods.dev/badge/skills/livsy90/ios-performance-agent-skills/ios-perceived-performance.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 89 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,025 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 high

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 →

  • high Memory Poisoning · line 121
    Skill manipulates agent memory, state, or stored context. Memory corruption can alter personality, override safety rules, or cause unpredictable behavior.
    Fix: Protect agent memory and state from modification by untrusted content. Use read-only memory for critical instructions and validate all state changes.
How audits are shown
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 $0.00089 $0.02025
Opus 5 $0.00044 $0.01012
Sonnet 5 $0.00018 $0.00405
Haiku 4.5 $0.00009 $0.00202

Measured 11d ago against content hash f9428a6b99c1, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-11, from the pricing page.

Security

Grade A, and why

ios-perceived-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 11d 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.

ios-perceived-performance/SKILL.md · 194 lines

How it starts

The opening of the file, as written. The whole thing — 194 lines — stays where its author put it; the contents beside it link to each section on GitHub.

iOS Perceived Performance

Purpose

Use this skill to review whether an iOS screen or flow feels responsive to users, even when raw execution time does not change.

This skill focuses on user-visible feedback, loading behavior, staged content, continuity, optimistic UI, high-stakes actions, and validation of perceived responsiveness.

When to use this skill

Use this skill when the task involves:

  • a screen that feels slow, stuck, blank, jumpy, or unresponsive;
  • no visible feedback after a tap or gesture;
  • delayed first meaningful content;
  • loading states, placeholders, skeletons, empty states, retry states, or refresh states;
  • progressive rendering, partial content, section-level loading, or stale-while-refreshing UI;
  • optimistic updates, pending state, rollback, retries, or local/server reconciliation;
  • high-stakes, irreversible, destructive, financial, legal, medical, identity, or security-sensitive actions;
  • duplicate submissions or repeated taps during async work;
  • perceived latency trade-offs where the product behavior matters as much as the raw duration;
  • validation using recordings, UI tests, Instruments, MetricKit, production logs, or user-visible signals.

When not to use this skill

Do not use this skill for:

  • low-level CPU, allocation, ARC, memory, runtime, or compiler-performance investigations;
  • SwiftUI invalidation, identity, layout, or scrolling problems unless the question is about perceived responsiveness;
  • Swift Concurrency internals unless task behavior affects visible UI feedback or staged loading;
  • app launch performance unless the question is about first useful screen or first interaction from the user's point of view;
  • visual redesign requests with no responsiveness, loading, or feedback concern;
  • claims that require running the app when no runtime evidence is available.

Use ios-performance-profiling, swiftui-performance, swift-concurrency-performance, swift-runtime-performance, or ios-launch-performance when those domains are the primary problem.

Read the full file on GitHub · 194 lines

Files

What ships with it

6 files 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. 11d ago First seen · 194 lines · 89 tokens per session scan A f9428a6b99c1

Subscribe to this mod's changes

ios-perceived-performance is a skill published in the GitHub repository Livsy90/iOS-Performance-Agent-Skills (113 stars, last pushed 2mo ago), licensed MIT. It adds 89 tokens to every session and 2,025 once invoked, about $0.0004 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 2026-08-30.

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