How do I install the Disk Usage skill?

Run npx skillmds@latest add dennisonbertram/disk-usage in your terminal (requires Node.js), paste this page's agent-chat prompt into Claude, Cursor, or any MCP-connected agent, or download the SKILL.md file and copy it into your agent's skills directory.

Is Disk Usage safe to use?

This skill has not completed SkillMD's automated safety review yet. SkillMD never runs a skill's scripts for you; review the SKILL.md before installing.

Which AI agents work with Disk Usage?

This skill is tagged as working with Claude Code, Claude.ai, OpenAI Codex. SKILL.md is an open format, so most agents that read a skills directory can load it too.

Is Disk Usage free to use?

Yes. Installing skills from SkillMD is free, and the skill stays under its author's original license.

Who published Disk Usage?

dennisonbertram (@dennisonbertram) published this skill. Their other Agent Skills are listed on their SkillMD profile.

Disk Usage by dennisonbertram — Agent Skill

Name: Disk Usage
Author: dennisonbertram

Disk Usage

This skill should be used when the user asks to "check disk usage", "is my drive full", "what's using my disk", "disk space", "free up space", or mentions low storage. Reports free space, largest directories, caches, Time Machine local snapshots, Xcode simulator footprint, and node_modules sizes, then writes a JSON result to ~/.mac-guardian/data/.

File contents

disk-usage

Surveys storage usage on macOS without deleting anything.

When to invoke

Trigger on phrases like: "check disk usage", "is my drive full", "what's using my disk", "disk space", "free up space".

What to check

1. Per-volume free space — df -h. Filter to apfs and hfs volumes. For each volume:

/ free ≥ 20 GB or ≥ 15%: ok.
/ free 10–20 GB or 5–15%: info.
/ free 5–10 GB or 2–5%: warn.
/ free < 5 GB or < 2%: critical.

2. Top 20 home directories by size — du -shx ~/* 2>/dev/null | sort -rh | head -20. Record as raw. Individual dirs ≥ 50 GB get an info finding.

3. Library caches — du -shx ~/Library/Caches 2>/dev/null. If ≥ 20 GB, info "Library caches at ".

4. System / user log sizes — du -shx ~/Library/Logs /private/var/log 2>/dev/null. Record in raw.

5. Time Machine local snapshots — tmutil listlocalsnapshots / 2>/dev/null. Report the count. ≥ 10 snapshots: info.

6. Xcode / iOS simulator footprint — du -shx ~/Library/Developer/CoreSimulator/Devices ~/Library/Developer/Xcode/DerivedData ~/Library/Developer/Xcode/iOS\ DeviceSupport 2>/dev/null. Sum ≥ 30 GB: info. Sum ≥ 100 GB: warn.

7. node_modules across common dev roots (optional and guarded) — only run when the user's home has a Develop/ or Projects/ or code/ directory: find ~/Develop ~/Projects ~/code -type d -name node_modules -maxdepth 6 -prune -exec du -shx {} + 2>/dev/null | sort -rh | head -20. Guard this with a soft timeout (use timeout 60s if gtimeout or coreutils timeout is available; otherwise include only if find completes within reason, and skip with an info finding "skipped — search would take too long" if not).

8. Large Downloads / Trash — du -shx ~/Downloads ~/.Trash 2>/dev/null. Each ≥ 10 GB: info.

Output contract

Standard envelope. Write to ~/.mac-guardian/data/disk-usage-<ISOdate>.json.

Top-level severity = max across all checks. Summary example: "44 GB free on / (warn). Biggest: ~/Library/Caches 38 GB, DerivedData 27 GB."

Handoff

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

Safety

Read-only. Never delete caches, snapshots, DerivedData, or node_modules.
If the user asks to clean up after seeing the report, explain what the commands would be and prompt for confirmation.
Do not call sudo.

---name: disk-usagedescription: This skill should be used when the user asks to "check disk usage", "is my drive full", "what's using my disk", "disk space", "free up space", or mentions low storage. Reports free space, largest directories, caches, Time Machine local snapshots, Xcode simulator footprint, and node_modules sizes, then writes a JSON result to ~/.mac-guardian/data/.---# disk-usageSurveys storage usage on macOS without deleting anything.## When to invokeTrigger on phrases like: "check disk usage", "is my drive full", "what's using my disk", "disk space", "free up space".## What to check**1. Per-volume free space** — `df -h`. Filter to `apfs` and `hfs` volumes. For each volume:- `/` free ≥ 20 GB or ≥ 15%: `ok`.- `/` free 10–20 GB or 5–15%: `info`.- `/` free 5–10 GB or 2–5%: `warn`.- `/` free < 5 GB or < 2%: `critical`.**2. Top 20 home directories by size** — `du -shx ~/* 2>/dev/null | sort -rh | head -20`. Record as raw. Individual dirs ≥ 50 GB get an `info` finding.**3. Library caches** — `du -shx ~/Library/Caches 2>/dev/null`. If ≥ 20 GB, `info` "Library caches at <size>".**4. System / user log sizes** — `du -shx ~/Library/Logs /private/var/log 2>/dev/null`. Record in raw.**5. Time Machine local snapshots** — `tmutil listlocalsnapshots / 2>/dev/null`. Report the count. ≥ 10 snapshots: `info`.**6. Xcode / iOS simulator footprint** — `du -shx ~/Library/Developer/CoreSimulator/Devices ~/Library/Developer/Xcode/DerivedData ~/Library/Developer/Xcode/iOS\ DeviceSupport 2>/dev/null`. Sum ≥ 30 GB: `info`. Sum ≥ 100 GB: `warn`.**7. node_modules across common dev roots (optional and guarded)** — only run when the user's home has a `Develop/` or `Projects/` or `code/` directory: `find ~/Develop ~/Projects ~/code -type d -name node_modules -maxdepth 6 -prune -exec du -shx {} + 2>/dev/null | sort -rh | head -20`. Guard this with a soft timeout (use `timeout 60s` if `gtimeout` or coreutils `timeout` is available; otherwise include only if `find` completes within reason, and skip with an `info` finding "skipped — search would take too long" if not).**8. Large Downloads / Trash** — `du -shx ~/Downloads ~/.Trash 2>/dev/null`. Each ≥ 10 GB: `info`.## Output contractStandard envelope. Write to `~/.mac-guardian/data/disk-usage-<ISOdate>.json`.Top-level severity = max across all checks. Summary example: "44 GB free on / (warn). Biggest: ~/Library/Caches 38 GB, DerivedData 27 GB."## Handoff- On direct invocation: `bash ${CLAUDE_PLUGIN_ROOT}/scripts/render-single.sh disk-usage`.- When invoked by `daily-health-report`, return JSON path only.## Safety- Read-only. Never delete caches, snapshots, DerivedData, or node_modules.- If the user asks to clean up after seeing the report, explain what the commands would be and prompt for confirmation.- Do not call `sudo`.

Frequently asked questions