File Storage Audit

I'll perform a comprehensive file storage audit of your iOS/macOS codebase, checking for the most critical issues that cause data loss, backup bloat, and file access errors.

What I'll Check

1. Files in tmp/ Directory (CRITICAL)

Pattern: File writes to NSTemporaryDirectory() or tmp/ that aren't truly temporary Impact: iOS aggressively purges tmp/ - users lose data Risk: Data loss after device restart or storage pressure

2. Large Files Missing isExcludedFromBackup (HIGH)

Pattern: Files >1MB in Documents/ or Application Support/ without isExcludedFromBackupImpact: User's iCloud quota filled unnecessarily Risk: Backup bloat, iCloud storage pressure

3. Missing File Protection (MEDIUM)

Pattern: File writes without specifying FileProtectionTypeImpact: Sensitive data not encrypted at rest Risk: Security vulnerability, unauthorized data access

4. Wrong Storage Location (HIGH)

Pattern: Files stored in inappropriate directories Examples:

• User content in Application Support/ (not visible in Files app)
• Re-downloadable content in Documents/ (backup bloat)
• App data in tmp/ (data loss) Impact: User confusion, data loss, backup bloat

5. UserDefaults Abuse (MEDIUM)

Pattern: Storing >1MB data in UserDefaults Impact: Performance degradation on app launch Risk: Not designed for large data storage

Audit Process

1. Glob for all Swift files: **/*.swift
2. Search for storage anti-patterns using regex
3. Report findings with:
   • file:line references
   • Severity: CRITICAL/HIGH/MEDIUM/LOW
   • Risk description
   • Fix recommendation
   • Link to axiom:storage skill for decision framework

Output Format

=== FILE STORAGE AUDIT RESULTS ===

CRITICAL Issues (Data Loss Risk):
- src/Managers/DownloadManager.swift:45 - Writing to tmp/
  Risk: iOS purges tmp/ aggressively - downloads will be lost
  Fix: Move to Caches/ with isExcludedFromBackup:
    let cacheURL = FileManager.default.urls(for: .cachesDirectory, in: .userDomainMask)[0]
    var resourceValues = URLResourceValues()
    resourceValues.isExcludedFromBackup = true
    try downloadURL.setResourceValues(resourceValues)

HIGH Issues (Backup Bloat / Wrong Location):
- src/Cache/ImageCache.swift:67 - Large files in Documents/ without backup exclusion
  Impact: 500MB backed to iCloud (wastes user quota)
  Fix: Either move to Caches/ OR set isExcludedFromBackup

MEDIUM Issues (Security / Performance):
- src/Services/AuthManager.swift:34 - Writing token without file protection
  Risk: Sensitive data not encrypted at rest
  Fix: try tokenData.write(to: tokenURL, options: .completeFileProtection)

=== NEXT STEPS ===

For storage decision framework:
  /skill axiom:storage

For debugging missing files:
  /skill axiom:storage-diag

Storage Summary:
- CRITICAL Issues: 1 (immediate data loss risk)
- HIGH Issues: 2 (backup bloat, wrong location)
- MEDIUM Issues: 1 (security risk)

Detection Patterns

Files in tmp/

// BAD - Data loss risk
let tmpURL = FileManager.default.temporaryDirectory
try data.write(to: tmpURL.appendingPathComponent("download.pdf"))

// GOOD - Survives reboot
let cacheURL = FileManager.default.urls(for: .cachesDirectory, in: .userDomainMask)[0]
let downloadURL = cacheURL.appendingPathComponent("download.pdf")
try data.write(to: downloadURL)
var resourceValues = URLResourceValues()
resourceValues.isExcludedFromBackup = true
try downloadURL.setResourceValues(resourceValues)

Missing Backup Exclusion

// BAD - Backs up re-downloadable content
let documentsURL = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask)[0]
try largeImage.write(to: documentsURL.appendingPathComponent("cached.jpg"))

// GOOD - Excluded from backup
var resourceValues = URLResourceValues()
resourceValues.isExcludedFromBackup = true
try imageURL.setResourceValues(resourceValues)

Missing File Protection

// BAD - No encryption
try tokenData.write(to: tokenURL)

// GOOD - Encrypted at rest
try tokenData.write(to: tokenURL, options: .completeFileProtection)

Wrong Location

// BAD - User docs in hidden location
let appSupportURL = FileManager.default.urls(for: .applicationSupportDirectory, in: .userDomainMask)[0]
try userDocument.write(to: appSupportURL.appendingPathComponent("report.pdf"))

// GOOD - User-visible in Files app
let documentsURL = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask)[0]
try userDocument.write(to: documentsURL.appendingPathComponent("report.pdf"))

UserDefaults Abuse

// BAD - Large data in UserDefaults
UserDefaults.standard.set(largeData, forKey: "cache") // 2MB+

// GOOD - Use file storage
let appSupportURL = FileManager.default.urls(for: .applicationSupportDirectory, in: .userDomainMask)[0]
let cacheURL = appSupportURL.appendingPathComponent("cache.json")
try largeData.write(to: cacheURL)

Search Queries I'll Run

1. tmp/ Usage: Grep "NSTemporaryDirectory|temporaryDirectory|/tmp/"
2. Backup Exclusion: Grep "\.write\(to:|Data\(contentsOf:" -A 5 (check for isExcludedFromBackup)
3. File Protection: Grep "\.write\(to:|createFile" -A 5 (check for .completeFileProtection)
4. UserDefaults Size: Grep "UserDefaults.*set.*Data\(|UserDefaults.*set.*\["
5. Wrong Locations: Grep "/Documents/|/Library/|/tmp/" (hardcoded paths)

Storage Location Decision Tree

What are you storing?

User-created documents (PDF, images, text)?
  → Documents/ (user-visible in Files app, backed up)

App data (settings, cache, state)?
  ├─ Can regenerate/re-download? → Caches/ + isExcludedFromBackup
  └─ Can't regenerate? → Application Support/ (backed up, hidden)

Truly temporary (<1 hour lifetime)?
  → tmp/ (aggressive purging)

Limitations

• Cannot detect: Runtime file sizes, actual backup size, runtime storage pressure
• False positives: Truly temporary files in tmp/ (deleted within minutes)
• Test with low storage scenarios after fixes

Post-Audit

After fixing issues:

1. Test file persistence after device reboot
2. Test storage pressure (fill device to <500MB free)
3. Check backup size: Settings → [Profile] → iCloud → Manage Storage → [App]
4. Verify file locations with Files app

For comprehensive storage guidance:

• /skill axiom:storage — Storage decision framework
• /skill axiom:file-protection-ref — Encryption details
• /skill axiom:storage-management-ref — Purging policies