swiftdata-auditor

swiftdata-auditor is an agent for Claude Code from CharlesWiltgen/Axiom. It costs 250 tokens per session (3,835 once invoked), scanned A, original, MIT.

A code-review agent for SwiftData, Apple's framework for storing app data, that checks models, relationships, migrations, and performance-related problems.

In plain words
What is it for?
Use it when reviewing SwiftData models, `@Model` declarations, relationships, migration safety, background contexts, or performance.
Why use it?
SwiftData mistakes can cause crashes, lost or corrupted data, sync failures, or slow apps. The agent checks the repository for critical violations instead of relying on a quick manual review.

Agent for Claude Code

Written for Claude Code: background in frontmatter. Also seen: model in frontmatter.

Part of the axiom plugin — 27 skills, 17 commands, 42 agents, 5 hooks shipped together

Good fit Use it when reviewing SwiftData models, @Model declarations, relationships, migration safety, background…

Compare 6 agents from other repositories ↓
Install with agentmods
npx agentmods add agents/charleswiltgen/axiom/swiftdata-auditor
About the project

Axiom is a toolkit of instructions, agents, commands, and development tools that give coding assistants specialized guidance for Apple operating-system development. It covers Swift, SwiftUI, interface design, data, concurrency, performance, networking, accessibility, logging, crash analysis, simulator testing, and profiling for iOS, iPadOS, watchOS, and tvOS. The catalogue contains 42 agents, 16 commands, and one plugin from this toolkit.

CharlesWiltgen/Axiom · 1,148 stars · on GitHub · charleswiltgen.github.io

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.

Clone the repo
git clone --depth 1 https://github.com/CharlesWiltgen/Axiom

Made for: Claude Code.

Or install axiom, the plugin that ships this one along with the rest of its 27 skills, 17 commands, 42 agents, 5 hooks.

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-auditor

README.md
[![agentmods](https://agentmods.dev/badge/agents/charleswiltgen/axiom/swiftdata-auditor.svg)](https://agentmods.dev/agents/charleswiltgen/axiom/swiftdata-auditor)
Your own site
<a href="https://agentmods.dev/agents/charleswiltgen/axiom/swiftdata-auditor"><img src="https://agentmods.dev/badge/agents/charleswiltgen/axiom/swiftdata-auditor.svg" alt="Measured on agentmods" height="20"></a>
Per session 250 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 3,835 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 $0.00250 $0.03835
Opus 5 $0.00125 $0.01917
Sonnet 5 $0.00050 $0.00767
Haiku 4.5 $0.00025 $0.00383

Measured 7d ago against content hash 7a927d29d25c, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-06, from the pricing page.

Security

Grade A, and why

swiftdata-auditor 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 7d 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-plugin/plugins/axiom/agents/swiftdata-auditor.md · 321 lines

How it starts

The opening of the file, as written. The whole thing — 321 lines — stays where its author put it; the contents beside it link to each section on GitHub.

SwiftData Auditor Agent

You are an expert at detecting SwiftData violations — both known anti-patterns AND missing/incomplete patterns that cause crashes, data loss, silent corruption, sync failures, and performance degradation.

Tool Use Is Mandatory

Run every Glob, Grep, and Read this prompt lists. Do not reason from training data instead of scanning.

  • Run each Grep pattern as written; do not collapse them into one mega-regex.
  • Run the Read verifications each section calls for.
  • "Build a mental model" / "map the architecture" means with tool output in hand, not from memory.

Files to Exclude

Skip: *Tests.swift, *Previews.swift, */Pods/*, */Carthage/*, */.build/*, */DerivedData/*, */scratch/*, */docs/*, */.claude/*, */.claude-plugin/*

Phase 1: Map SwiftData Architecture

Step 1: Identify the @Model Inventory

Glob: **/*.swift (excluding test/vendor paths)
Grep for:
  - `@Model\s+(final\s+)?class\s+\w+` — every @Model class declaration
  - `@Model\s+struct` — illegal struct models (Pattern 1)
  - `@Attribute(` — attribute customization
  - `@Relationship(` — relationship declarations and inverses
  - `@Transient` — properties excluded from persistence

Step 2: Identify Container & Context Topology

Grep for:
  - `ModelContainer(` — container construction sites
  - `ModelConfiguration(` — configuration (App Group, CloudKit, in-memory)
  - `.modelContainer(` — view modifier hookup
  - `@Environment(\.modelContext)` — UI-side context use
  - `ModelContext(` — explicit (often background) context creation
  - `mainContext` — explicit main-context access
  - `isAutosaveEnabled` — autosave configuration

Step 3: Identify Migration Surface

Grep for:
  - `VersionedSchema` — schema versions
  - `static var versionIdentifier` — version markers
  - `static var models` — model arrays per version
  - `SchemaMigrationPlan` — migration plan
  - `MigrationStage.lightweight`, `MigrationStage.custom` — stage types
  - `willMigrate`, `didMigrate` — custom migration hooks

Read the full file on GitHub · 321 lines

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. 7d ago First seen · 321 lines · 250 tokens per session scan A 7a927d29d25c

Subscribe to this mod's changes

swiftdata-auditor is an agent published in the GitHub repository CharlesWiltgen/Axiom (1,148 stars, last pushed yesterday), licensed MIT. It adds 250 tokens to every session and 3,835 once invoked, about $0.0013 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.