AppBootstrapAI: Skill for Claude Code

.claude/skills/coredata-swift6-pro/SKILL.md

coredata-swift6-pro is a skill for Claude Code from kelvinkosbab/AppBootstrapAI. It costs 44 tokens per session (1,015 once invoked), scanned A, original, MIT.

A Swift code reviewer for Core Data, Apple’s framework for storing and querying app data, under Swift 6’s stricter concurrency rules. It checks which thread or actor accesses data and how data models are packaged with Swift Package Manager.

In plain words
What is it for?
Use it to review or write Core Data code involving the main context, background contexts, persistent containers, fetch results, object identifiers, and Swift Package Manager support.
Why use it?
It helps prevent unsafe access to stored objects from the wrong part of the program and errors caused by passing those objects between execution contexts. It also catches packaging problems in Swift packages.

Skill for Claude Code

Written for Claude Code: installed under .claude/.

This is kelvinkosbab/AppBootstrapAI's own configuration. It tells Claude Code how to work on AppBootstrapAI itself, so it is not a mod to install elsewhere. Copy it as a starting point and replace the rules that are about this project. Everything AppBootstrapAI configures →

Reuse

Borrowing it

Nothing to install: this file belongs to kelvinkosbab/AppBootstrapAI. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file
curl -O https://raw.githubusercontent.com/kelvinkosbab/AppBootstrapAI/main/.claude/skills/coredata-swift6-pro/SKILL.md
Clone the repo
git clone --depth 1 https://github.com/kelvinkosbab/AppBootstrapAI

Made for: Claude Code.

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 coredata-swift6-pro

README.md
[![agentmods](https://agentmods.dev/badge/skills/kelvinkosbab/appbootstrapai/coredata-swift6-pro/github.svg)](https://agentmods.dev/skills/kelvinkosbab/appbootstrapai/coredata-swift6-pro)
Your own site
<a href="https://agentmods.dev/skills/kelvinkosbab/appbootstrapai/coredata-swift6-pro"><img src="https://agentmods.dev/badge/skills/kelvinkosbab/appbootstrapai/coredata-swift6-pro/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 coredata-swift6-pro

Your own site · 80×15
<a href="https://agentmods.dev/skills/kelvinkosbab/appbootstrapai/coredata-swift6-pro"><img src="https://agentmods.dev/badge/skills/kelvinkosbab/appbootstrapai/coredata-swift6-pro.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 44 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,015 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 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 $0.00044 $0.01015
Opus 5 $0.00022 $0.00508
Sonnet 5 $0.00009 $0.00203
Haiku 4.5 $0.00004 $0.00102

Measured 11d ago against content hash ab0426c900e8, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-11, from the pricing page.

Security

Grade A, and why

coredata-swift6-pro 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.

.claude/skills/coredata-swift6-pro/SKILL.md · 111 lines

How it starts

The opening of the file, as written. The whole thing — 111 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Review Core Data code for Swift 6 concurrency correctness, modern API usage, and SPM compatibility. Report only genuine problems - do not nitpick or invent issues.

Review process:

  1. Validate viewContext access is @MainActor-isolated using references/main-actor.md.
  2. Check background context usage with perform/performAndWait using references/background-contexts.md.
  3. Verify SPM compatibility for .xcdatamodeld bundling using references/spm-limitations.md.
  4. Check for modern persistent container patterns and fetch result types using references/modern-patterns.md.
  5. Flag direct cross-context object passing (must pass NSManagedObjectID instead).

If doing a partial review, load only the relevant reference files.

Core Instructions

  • Target Swift 6 with strict concurrency. Core Data + Swift 6 has specific rules that must be followed.
  • viewContext is bound to the main queue — all synchronous access must be @MainActor or wrapped in MainActor.run.
  • NSManagedObject subclasses are NOT Sendable. Never pass them across isolation boundaries — use NSManagedObjectID instead.
  • All background context work goes through context.perform { } (async) or context.performAndWait { } (sync).
  • For SPM packages, .xcdatamodeld cannot be compiled to .momd by swift build — only Xcode can. Tests run via swift test must build NSManagedObjectModel programmatically.
  • Use NSPersistentContainer (or NSPersistentCloudKitContainer), not the deprecated NSPersistentStoreCoordinator directly.
  • Prefer .viewContext.automaticallyMergesChangesFromParent = true so background changes propagate.
  • For tests, use NSInMemoryStoreType so each test has an isolated store.

Output Format

Organize findings by file. For each issue:

  1. State the file and relevant line(s).
  2. Name the rule being violated.
  3. Show a brief before/after code fix.

Skip files with no issues. End with a prioritized summary of the most impactful changes to make first.

Read the full file on GitHub · 111 lines

Files

What ships with it

4 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 · 111 lines · 44 tokens per session scan A ab0426c900e8

Subscribe to this mod's changes

coredata-swift6-pro is a skill published in the GitHub repository kelvinkosbab/AppBootstrapAI (6 stars, last pushed yesterday), licensed MIT. It adds 44 tokens to every session and 1,015 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 2026-08-31.

Related

Other skills, from other repositories

kotlin-concurrency-and-flow

Use when writing or reviewing Kotlin coroutine scope ownership, raw Thread or Executor work, init launches, non-suspending launch APIs, runBlocking, cancellation, StateFlow, SharedFlow, Channel, stateIn, SharingStarted, state updates, or one-shot events.

chrisbanes/skills · 60 tokens

kotlin-api-design

Use when designing or reviewing Kotlin function ownership, member or extension functions, factories, single-field domain types, value classes, data classes, Kotlin Multiplatform expect/actual declarations, or platform service boundaries.

chrisbanes/skills · 46 tokens

swiftlint

Configure and roll out SwiftLint for an iOS/Swift (or KMP-iOS) fintech app — author .swiftlint.yml (disabledrules / optinrules / onlyrules / analyzerrules / included / excluded / customrules, per-rule severity thresholds, parentconfig / childconfig), wire it via the SwiftLintPlugins SPM build-tool plugin (SimplyDanny)…

TalissonVitorino/kmp-ios-skills · 251 tokens

compose-animations

Use when writing or reviewing Jetpack Compose motion: visibility enter/exit, animating one property toward a target, color or size transitions, multiple properties from one state, switching composable content, or choosing between AnimatedVisibility, animateAsState, rememberTransition, AnimatedContent, and Crossfade.

chrisbanes/skills · 64 tokens

compose-focus-navigation

Use when writing or reviewing Jetpack Compose UI for TV, keyboard, desktop, accessibility focus, D-pad navigation, FocusRequester, focusProperties, key events, or initial focus behavior.

chrisbanes/skills · 41 tokens

kotlin-control-flow

Use when writing or reviewing Kotlin branching and control flow: when expressions, guard conditions, sealed type exhaustiveness, smart casts, nullable branching, early returns, or replacing complex if/else chains.

chrisbanes/skills · 44 tokens