swiftui-performance-audit

Audit and improve SwiftUI runtime performance from code review and architecture. Use for requests to diagnose slow rendering, janky scrolling, high CPU/memory usage, excessive view updates, or layout thrash in SwiftUI apps, and to provide guidance for user-run Instruments profiling when code review alone is insufficient.

Install with Tessl CLI

npx tessl i github:Dimillian/Skills --skill swiftui-performance-audit

What are skills?

100

Review — 100%

Does it follow best practices?

Validation — 11 / 11 Passed

Validation for skill structure

SKILL.md

Review

Evals

Evaluation results

100%

Fitness Tracker App — Performance Audit

Heavy body computation anti-patterns

Criteria

Without context

With context

Formatter in body

100%

Formatter cache fix

100%

Inline sort in ForEach

100%

Sort precomputation fix

100%

Computed filter on every eval

100%

Filter cache fix

100%

Impact ordering

100%

Proposed fix per issue

100%

NumberFormatter issue

100%

Body work explanation

100%

Without context: $0.2331 · 1m 18s · 6 turns · 7 in / 4,969 out tokens

With context: $0.4238 · 2m 8s · 15 turns · 96 in / 7,110 out tokens

92%

13%

Social Reading App — Excessive Re-render Investigation

Unstable identity and broad state dependencies

Criteria

Without context

With context

Broad observable dependency

100%

Granular view model fix

50%

100%

Top-level conditional swapping

100%

Stable base view fix

80%

100%

Narrow state scope

90%

FavoriteTagView fan-out

70%

60%

Avoiding environment for fast-changing values

10%

70%

Impact ordering

100%

Proposed fix per issue

100%

Update fan-out explanation

90%

100%

Without context: $0.3109 · 1m 58s · 7 turns · 8 in / 6,810 out tokens

With context: $0.4978 · 3m 8s · 14 turns · 13 in / 9,236 out tokens

90%

20%

Travel Photo Gallery — Performance Audit

Image decoding and layout thrash

Criteria

Without context

With context

Main-thread image decode

100%

Off-thread decode fix

100%

Image downsampling

GeometryReader layout thrash

100%

Reduce GeometryReader fix

100%

Top-level conditional swapping

100%

Stable overlay fix

100%

Formatter allocation in overlay

100%

Formatter cache fix

100%

Impact ordering

100%

Without context: $0.3076 · 1m 37s · 9 turns · 10 in / 5,954 out tokens

With context: $0.4788 · 2m 33s · 14 turns · 13 in / 8,533 out tokens

Evaluated: 3 days ago
Agent: Claude Code

Table of Contents

Fitness Tracker App — Performance Audit Social Reading App — Excessive Re-render Investigation Travel Photo Gallery — Performance Audit

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