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 mwd1234/ios-agentic-skills --skill data-modeling-and-syncgit clone --depth 1 https://github.com/mwd1234/ios-agentic-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/mwd1234/ios-agentic-skills/data-modeling-and-sync)<a href="https://agentmods.dev/skills/mwd1234/ios-agentic-skills/data-modeling-and-sync"><img src="https://agentmods.dev/badge/skills/mwd1234/ios-agentic-skills/data-modeling-and-sync/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/mwd1234/ios-agentic-skills/data-modeling-and-sync"><img src="https://agentmods.dev/badge/skills/mwd1234/ios-agentic-skills/data-modeling-and-sync.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 | $0.00032 | $0.00490 |
| Opus 5 | $0.00016 | $0.00245 |
| Sonnet 5 | $0.00006 | $0.00098 |
| Haiku 4.5 | $0.00003 | $0.00049 |
Grade A, and why
data-modeling-and-sync scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 10d ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
What it actually says
Data Modeling & Sync
Ensure data integrity across iPhone and Apple Watch, with predictable conflict handling and resilient offline behavior.
When to use this skill
- When adding new data models or persistence changes
- After any WCSession messaging changes
- Before App Store submission
- When users report missing or out-of-sync data
Step 1: Model Stability & Migrations
Checklist:
- Models have stable identifiers (UUID or stable hash)
- Stored models include schema version
- Migration strategy exists for added/removed fields
If using Codable + UserDefaults:
- Provide default values for new fields
- Handle missing keys gracefully
Step 2: WCSession Reliability
WATCH_DIR="YourApp Watch App"
# WCSession usage
rg --type swift 'WCSession|sendMessage|transferUserInfo|updateApplicationContext' "$WATCH_DIR/"
rg --type swift 'WCSession' YourApp/
Checklist:
WCSession.isReachableonly used for interactive UI messagestransferUserInfofor eventual deliveryupdateApplicationContextfor latest state only- Retries or fallbacks for failures
Step 3: Conflict Resolution
Define a clear strategy:
- Last-write-wins with timestamps, or
- Merge by stable ID, or
- User choice for conflicts
Ensure conflict handling is deterministic and tested.
Step 4: Offline & Edge Cases
Checklist:
- App behaves predictably offline
- Pending changes queued and replayed
- No data loss if watch/app restarts mid-sync
Step 5: Data Integrity Tests
Suggested tests:
- Encode/decode round-trip for each model
- Migration tests between schema versions
- Sync payload validation
- Conflict-resolution unit tests
Output Format
| Category | Issues | Status |
|---|---|---|
| Model stability | X | ✅/❌ |
| Migration strategy | X | ✅/❌ |
| WCSession reliability | X | ✅/❌ |
| Conflict handling | X | ✅/❌ |
| Offline behavior | X | ✅/❌ |
| Integrity tests | X | ✅/❌ |
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.
- 10d ago First seen · 90 lines · 32 tokens per session scan A d34b9ab45b45
data-modeling-and-sync is a skill published in the GitHub repository mwd1234/ios-agentic-skills (50 stars, last pushed 7mo ago), licensed MIT. It adds 32 tokens to every session and 490 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 2026-08-30.
Other skills, from other repositories
setup-datamodel
Use when the user wants to design or redesign the Dataverse schema and connector plan for an existing mobile app, or has an ER diagram (image, Mermaid, or text) to apply. Skip when the user is creating a brand-new app — /create-mobile-app handles the data model inline.
axiom-audit-core-data
Use when the user mentions Core Data review, schema migration, production crashes, or data safety checking.
axiom-audit-swiftdata
Use when the user mentions SwiftData review, @Model issues, SwiftData migration safety, or SwiftData performance checking.
firebase-database
Use when syncing real-time data, structuring JSON trees, reading/writing, creating listeners, enabling offline persistence, managing presence, sharding, or writing security rules.
axiom-data
Use when working with ANY data persistence, database, storage, CloudKit, migration, or serialization. Covers SwiftData, Core Data, GRDB, SQLite, Realm, CloudKit sync, file storage, Codable, migrations.
android-data-layer
Guidance on implementing the Data Layer using Repository pattern, Room (Local), and Retrofit (Remote) with offline-first synchronization.