performance-check

name	performance-check
description	This skill should be used when the user asks to "check performance", "mac is slow", "why is my mac slow", "cpu usage", "memory pressure", or "what's slowing me down". Reports load average, memory pressure, swap, top processes, thermal state, and battery health, then writes a JSON result to ~/.mac-guardian/data/.

performance-check

Captures a point-in-time performance snapshot on macOS.

When to invoke

Trigger on phrases like: "check performance", "mac is slow", "why is my mac slow", "cpu usage", "memory pressure", "what's slowing me down".

What to check

1. Load averages — sysctl -n vm.loadavg or uptime. Compare 1-minute load to sysctl -n hw.ncpu.

• load / ncpu < 0.7: ok
• 0.7–1.0: info
• 1.0–2.0: warn

• 2.0: critical

2. Memory pressure — vm_stat (pages free / active / inactive / speculative / wired). Compute pressure ratio: (free + inactive) / total.

• 20% free+inactive: ok

• 10–20%: info
• 5–10%: warn
• <5%: critical

Also parse memory_pressure output when available (memory_pressure 2>/dev/null | tail -5).

3. Swap usage — sysctl vm.swapusage. Parse "used = X.XXM".

• used = 0: ok
• used < 512 MB: info
• 512 MB – 2 GB: warn

• 2 GB: critical

4. Top 10 CPU consumers — top -l 1 -n 10 -o cpu -stats pid,command,cpu,mem. Record rows.

5. Top 10 memory consumers — top -l 1 -n 10 -o mem -stats pid,command,cpu,mem. Record rows.

6. Thermal state — pmset -g therm 2>/dev/null. Non-zero CPU_Speed_Limit = warn with the value.

7. Battery status (laptops only) — pmset -g batt. Parse percentage, AC Power/Battery Power, charging state. Low percentage on battery with no charger: info.

8. Battery health (laptops only) — ioreg -rc AppleSmartBattery 2>/dev/null. Extract CycleCount, MaxCapacity, DesignCapacity, AppleRawMaxCapacity. Compute MaxCapacity/DesignCapacity × 100:

• ≥ 85%: ok
• 75–85%: info
• 60–75%: warn
• < 60%: critical Skip gracefully on desktops.

9. Power summary — system_profiler SPPowerDataType 2>/dev/null | head -60 in raw.

10. Uptime — uptime. Uptime > 14 days: info "Consider rebooting; uptime N days."

Output contract

Standard envelope. Write to ~/.mac-guardian/data/performance-check-<ISOdate>.json.

Summary example: "Load 1.32 / 10, 18% memory free, swap 0.0 MB, battery health 92%."

Handoff

• On direct invocation: bash ${CLAUDE_PLUGIN_ROOT}/scripts/render-single.sh performance-check.
• When invoked by daily-health-report, return JSON path only.

Safety

• Read-only. Do not kill processes. Do not change pmset settings.
• No sudo.