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.
npx skills add Livsy90/iOS-Performance-Agent-Skills --skill swiftui-performancegit clone --depth 1 https://github.com/Livsy90/iOS-Performance-Agent-SkillsWrote 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.
[](https://agentmods.dev/skills/livsy90/ios-performance-agent-skills/swiftui-performance)<a href="https://agentmods.dev/skills/livsy90/ios-performance-agent-skills/swiftui-performance"><img src="https://agentmods.dev/badge/skills/livsy90/ios-performance-agent-skills/swiftui-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.
<a href="https://agentmods.dev/skills/livsy90/ios-performance-agent-skills/swiftui-performance"><img src="https://agentmods.dev/badge/skills/livsy90/ios-performance-agent-skills/swiftui-performance.svg" alt="Reviewed on agentmods" width="80" height="20"></a>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.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00076 | $0.01335 |
| Opus 5 | $0.00038 | $0.00668 |
| Sonnet 5 | $0.00015 | $0.00267 |
| Haiku 4.5 | $0.00008 | $0.00134 |
Grade A, and why
swiftui-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.
How it starts
The opening of the file, as written. The whole thing — 158 lines — stays where its author put it; the contents beside it link to each section on GitHub.
SwiftUI Performance
Purpose
Use this skill to review and refactor SwiftUI code with a performance-first mental model focused on change locality.
SwiftUI performance work should explain which change invalidates which part of the UI, why that work matters, and how to keep updates local.
Scope
Use this skill for:
- SwiftUI screen, list, row, layout, drawing, animation, and lifecycle reviews
- targeted refactors that reduce unnecessary updates or rendering work
- profiling plans only when they validate a SwiftUI performance hypothesis
Do not use this skill for:
- UIKit-only performance problems
- app launch performance unless the issue is inside SwiftUI root view or scene construction
- networking, backend latency, database performance, or caching unless they affect SwiftUI updates
- generic Instruments walkthroughs without a SwiftUI code path
- broad architecture rewrites without a concrete SwiftUI performance risk
Core Model
Answer three questions first:
- What changed?
- Which views depend on that change?
- How much UI work happens because of it?
Then inspect:
- Identity: does SwiftUI preserve the same logical view across updates?
- Lifetime: is state owned by the smallest stable component that needs it?
- Dependencies: does each view read only the data it needs to render?
- Rendering: is
bodycheap, predictable, and free from heavy transformation work? - Lifecycle: is async work tied to
.task,.onAppear, or explicit actions rather than started frombody?
A SwiftUI view is a value description of UI. Do not treat it as a long-lived UIKit-style object.
Review Workflow
Inspect the smallest relevant code path before suggesting broad changes.
Check in this order:
- Stable and intentional identity.
- Expensive work in
body. - Broad state or model reads.
- State ownership and lifetime.
- List, row, and pagination structure.
- Closure-heavy inputs, custom bindings, and unnecessary type erasure.
- Layout, drawing, and animation cost in repeated content.
- Async lifecycle, cancellation, and main-actor work.
- Profiling or debug probes when confirmation is useful.
What ships with it
9 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.
- agents/openai.yaml 298 B
- references/async-lifecycle-and-mainactor.md 16 KB
- references/body-cost-and-render-models.md 17 KB
- references/closures-bindings-and-equatable.md 22 KB
- references/identity-and-state.md 18 KB
- references/layout-drawing-and-animation.md 18 KB
- references/lists-pagination-and-rows.md 17 KB
- references/observation-and-dependencies.md 16 KB
- references/profiling-validation.md 26 KB
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.
- 11d ago First seen · 158 lines · 76 tokens per session scan A 6ea3651240cc
swiftui-performance is a skill published in the GitHub repository Livsy90/iOS-Performance-Agent-Skills (113 stars, last pushed 2mo ago), licensed MIT. It adds 76 tokens to every session and 1,335 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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