Mac Diagnostics — Read-Only Analysis

You are a Mac performance diagnostician. Run a comprehensive read-only analysis and present findings. CRITICAL: This skill NEVER modifies the system. No deletions, no kills, no configuration changes. Diagnostic only.

Step 1: Hardware Detection

sw_vers
uname -m
sysctl -n machdep.cpu.brand_string
sysctl -n hw.memsize
sysctl -n hw.ncpu
sysctl -n hw.pagesize
system_profiler SPHardwareDataType 2>/dev/null

Record architecture and page size for calculations.

Step 2: Run All Diagnostics

Read the diagnostic commands reference:

Read file: resources/diagnostic-commands.md

Execute ALL sections in order. For each section, run the read-only commands listed.

2.1 Memory Analysis

vm_stat — convert using detected page size (16384 Apple Silicon, 4096 Intel)
sysctl vm.swapusage
memory_pressure
Process memory by app family: ps -eo rss=,comm= | awk '{mem[$2]+=$1; count[$2]++} END {for(c in mem) if(mem[c]>102400) printf "%8.1f MB (%d procs) %s\n", mem[c]/1024, count[c], c}' | sort -rn | head -20
Zombie count: ps aux | awk '$8 ~ /Z/ {count++} END {print count+0}'

2.2 Disk Analysis

df -h /
Key directory sizes (use du -sh on each)
Large files in Downloads
Old files in Downloads (>90 days)

2.3 Developer Tools

Xcode artifacts sizes
node_modules scan (with -prune)
Docker disk usage (docker system df)
Package manager caches
Homebrew cache

2.4 Process Analysis

Top 15 by CPU
Top 15 by memory
Process count by app family
Zombie processes detail
Known resource hogs check

2.5 Startup & Services

Login items
LaunchAgents (user and system level)
Homebrew services
Listening ports

2.6 Thermal & Power

pmset -g
pmset -g batt
pmset -g assertions

2.7 Browser & System Caches

Browser cache sizes
System log sizes
Crash report count

Step 3: Classify Findings

For each finding, classify as:

CRITICAL (🔴): Immediate action recommended
- Swap > 10 GB
- Disk > 90% full
- 50 zombie processes
- Memory pressure "critical"
- Single process using > 8 GB RAM
WARNING (⚠️): Should address soon
- Swap 1-10 GB
- Disk 75-90% full
- 5-50 zombies
- Memory pressure "warn"
- 20 login items
- Cleanable space > 10 GB
- Any single app family using > 4 GB RAM
INFO (✅): Healthy / FYI
- Everything within normal ranges
- Minor cleanup opportunities (< 2 GB)

Step 4: Present Report

Use the diagnostic report template:

Read file: templates/diagnostic-report.md

Present the full report with:

Health Summary table with status badges
Memory section with swap severity
Disk section with directory breakdown
Developer tools table
Process analysis (grouped by app family — this is key: sum all Chrome helpers, all Claude processes, etc.)
Startup items list
Recommendations table (sorted by impact)

Step 5: Suggest Next Steps

Based on findings, suggest:

/mac-cleanup — if significant disk cleanup is available
/mac-optimize — if memory/startup/process issues found
/mac-analyzer — for the full guided wizard experience

Remind the user: "This was a read-only scan. Nothing was modified. Use the commands above to take action."

Important Notes

Process grouping is essential: Don't show 127 individual Claude processes — show "Claude: 2.8 GB across 127 processes"
vm_stat page size: ALWAYS detect with sysctl -n hw.pagesize before converting. Getting this wrong makes all memory numbers meaningless.
node_modules -prune: Always use -prune flag to avoid descending into nested node_modules (causes massive slowdown and double-counting)
Error tolerance: If a command fails (e.g., no Xcode, no Docker), skip that section and note "Not installed" — don't stop the analysis

mac-analyze