swiftdata-code-review

swiftdata-code-review is a skill for Claude Code from existential-birds/beagle. It costs 46 tokens per session (671 once invoked), scanned A, original, Apache-2.0.

A review guide for SwiftData, Apple's framework for storing app data in models and querying it. It checks model definitions, queries, concurrent access, and migrations between stored-data versions.

In plain words
What is it for?
Use it when reviewing Swift files that use SwiftData features such as @Model, @Query, @ModelActor, or VersionedSchema.
Why use it?
It helps find data-model mistakes, unsafe background operations, incorrect queries, and changes that could break existing user data.

Skill for Claude Code

Written for Claude Code: shipped in a Claude Code plugin.

Part of the beagle-ios plugin — 15 skills shipped together

Good fit Use it when reviewing Swift files that use SwiftData features such as @Model, @Query, @ModelActor, or VersionedSchema.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/existential-birds/beagle/swiftdata-code-review
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 existential-birds/beagle --skill swiftdata-code-review
Clone the repo
git clone --depth 1 https://github.com/existential-birds/beagle

Made for: Claude Code.

Or install beagle-ios, the plugin that ships this one along with the rest of its 15 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 swiftdata-code-review

README.md
[![agentmods](https://agentmods.dev/badge/skills/existential-birds/beagle/swiftdata-code-review/github.svg)](https://agentmods.dev/skills/existential-birds/beagle/swiftdata-code-review)
Your own site
<a href="https://agentmods.dev/skills/existential-birds/beagle/swiftdata-code-review"><img src="https://agentmods.dev/badge/skills/existential-birds/beagle/swiftdata-code-review/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 swiftdata-code-review

Your own site · 80×15
<a href="https://agentmods.dev/skills/existential-birds/beagle/swiftdata-code-review"><img src="https://agentmods.dev/badge/skills/existential-birds/beagle/swiftdata-code-review.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 46 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 671 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 $0.00046 $0.00671
Opus 5.5 $0.00018 $0.00268
Sonnet 5.5 $0.00009 $0.00134
Haiku 4.5 $0.00005 $0.00067

Measured 1mo ago against content hash 1be72ae3f577, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

swiftdata-code-review 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 1mo 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.

plugins/beagle-ios/skills/swiftdata-code-review/SKILL.md · 55 lines

How it starts

The opening of the file, as written. The whole thing — 55 lines — stays where its author put it; the contents beside it link to each section on GitHub.

SwiftData Code Review

Quick Reference

Issue Type Reference
@Model, @Attribute, @Relationship, delete rules references/model-design.md
@Query, #Predicate, FetchDescriptor, #Index references/queries.md
@ModelActor, ModelContext, background operations references/concurrency.md
VersionedSchema, MigrationStage, lightweight/custom references/migrations.md

Hard gates (before reporting findings)

Run in order; do not assert an issue until the gate for that issue passes.

  1. Scope — pass when: You have the target .swift path(s) and confirmed SwiftData surface in scope (e.g. import SwiftData, @Model, @Query, @ModelActor, VersionedSchema, or migration types). If none apply, stop or narrow scope with one sentence.
  2. Reference — pass when: For each checklist area you evaluate (models, queries, concurrency, migrations), you opened the matching references/*.md from the Quick Reference table or wrote N/A: no <area> in this review with a one-line reason.
  3. Evidence — pass when: Every finding uses the [FILE:LINE] ISSUE_TITLE header (line range allowed) from the file you read; no finding without a cite.
  4. Report — pass when: Findings list cites first (or inline) using [FILE:LINE] ISSUE_TITLE, then severity or checklist grouping—no uncited assertions.

Review Checklist

  • Models marked final (subclassing crashes)
  • @Relationship decorator on ONE side only (not both)
  • Delete rules explicitly set (not relying on default .nullify)
  • Relationships initialized to empty arrays, not default objects
  • Batch operations used for bulk inserts (append(contentsOf:))
  • @Query not loading thousands of items on main thread
  • External values in predicates captured in local variables
  • Scalar comparisons in predicates (not object references)
  • @ModelActor used for background operations
  • PersistentIdentifier/DTOs used to pass data between actors
  • VersionedSchema defined for each shipped version
  • MigrationPlan passed to ModelContainer

Read the full file on GitHub · 55 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. 1mo ago First seen · 55 lines · 46 tokens per session scan A 1be72ae3f577

Subscribe to this mod's changes

swiftdata-code-review is a skill published in the GitHub repository existential-birds/beagle (82 stars, last pushed 1mo ago), licensed Apache-2.0. It adds 46 tokens to every session and 671 once invoked, about $0.0002 per session on Opus 5.5. 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 2026-09-16.

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