Swift Logging Pro

Review Swift logging code for correctness, privacy compliance, and consistent subsystem conventions. Report only genuine problems - do not nitpick or invent issues.

Review process:

1. Check os.Logger usage and subsystem/category conventions using references/os-logger.md.
2. Validate privacy markers on logged values using references/privacy.md.
3. Verify log level choice matches the message severity using references/log-levels.md.
4. Flag print() statements in production code (acceptable in tests, scripts).

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

Core Instructions

• Use os.Logger (modern API), not OSLog (legacy) or print() (no privacy, no levels, no subsystem filtering).
• Always specify subsystem (typically reverse-DNS bundle ID) and category (component name) when creating a Logger.
• All interpolated values default to private — explicitly mark with .public only when safe (e.g., status enums, fixed strings).
• Never log usernames, passwords, tokens, email addresses, or PII — even with .public.
• Use the appropriate level: .debug for development noise, .info for normal events, .notice for important events, .error for recoverable failures, .fault for programmer errors.
• A single Logger instance per type/category — store as static let to avoid re-creating on each log call.

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.

Example output:

MyService.swift

Line 18: Privacy violation — user identifier logged as .public.

// Before
logger.info("Loaded user \(userId, privacy: .public)")

// After
logger.info("Loaded user \(userId, privacy: .private)")

Line 34: Use .error level for recoverable failures, not .info.

// Before
logger.info("Network request failed: \(error.localizedDescription)")

// After
logger.error("Network request failed: \(error.localizedDescription)")

Line 45: print() statement in production code — replace with Logger.

// Before
print("Cache miss for key \(key)")

// After
logger.debug("Cache miss for key \(key, privacy: .public)")

Summary

1. Privacy (high): User-identifying data logged as .public on line 18 — change to .private.
2. Severity (medium): Recoverable failure logged at .info — should be .error.
3. Modernization (low): print() statement should use Logger.

End of example.

References

• references/os-logger.md — os.Logger basics, subsystem/category conventions, instance creation patterns.
• references/privacy.md — .public, .private, .sensitive markers, redaction, what never to log.
• references/log-levels.md — .debug, .info, .notice, .error, .fault semantics, performance impact.

Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

• Author: kelvinkosbab
• Source: kelvinkosbab/AppBootstrapAI
• License: MIT

Install and usage instructions live in the source repository linked above.