Mac Disk Cleanup

Mac Disk Cleanup

Use this skill to reclaim macOS disk space without accidental data loss.

The default workflow is: read-only audit, trusted-tool research, action table, explicit batch approval, cleanup, verification, and durable notes.

Safety Rules

• Do not run destructive commands until the user approves the exact batch.
• Treat user media, Documents, Downloads, browser profiles, app support data, secrets, project data, active worktrees, virtualenvs, Docker volumes, Photos libraries, and external-drive moves as protected by default.
• Do not use /Volumes/* as an archive destination unless the user explicitly includes archive/offload scope.
• Ask narrowly for macOS privacy permissions only when a blocked path matters to an approved cleanup branch.
• Save one-off audit and cleanup scripts under the active task's task-progress-artifacts/scratchpad/ before running them.
• Capture before/after evidence for every cleanup batch.

Read-Only Audit

Start with bounded checks:

df -h / /System/Volumes/Data /Volumes/* 2>/dev/null
tmutil listlocalsnapshots / 2>&1
du -sh "$HOME/.cache" "$HOME/.npm" "$HOME/Library/Caches" "$HOME/Library/Logs" "$HOME/Library/Developer" 2>&1

Then inspect likely candidates, keeping output bounded:

• ~/.cache children.
• ~/Library/Caches children.
• ~/Library/Logs children.
• ~/Library/Developer/Xcode/DerivedData, Archives, iOS DeviceSupport.
• ~/Library/Developer/CoreSimulator.
• package-manager cache paths from owner commands.
• Docker state from docker system df.
• selected project build artifacts such as build, dist, .next, target, node_modules, .venv, and cache directories, without deleting them.
• user-facing folders such as Downloads/Documents only for size review.

Avoid broad recursive scans when the disk is critically low or macOS privacy blocks many subtrees.

Trusted Cleanup Mechanisms

Prefer owner commands over manual deletion:

• Homebrew: brew cleanup --dry-run --prune=all before brew cleanup --prune=all.
• npm: npm config get cache; npm cache clean --force only with approval.
• pnpm: pnpm store path; pnpm store prune.
• uv: uv cache dir; prefer uv cache prune over uv cache clean.
• pip: pip3 cache info; pip3 cache purge.
• Docker: docker system df; docker system prune -af only when volumes should be preserved.
• Xcode simulators: xcrun simctl list devices unavailable; xcrun simctl delete unavailable only if useful.

For current behavior, check installed help (<tool> --help) and official docs when needed. Record what was reused, avoided, or adapted.

Action Table

Before cleanup, write an action table with:

• path or command
• size/evidence
• risk
• exact proposed action
• reversibility
• approval status

Recommended batch categories:

• High-dividend generated data: Docker unused images/build cache without volumes, Xcode DerivedData, large app logs.
• Smaller package caches: Homebrew, npm, pnpm, uv, pip.
• Developer project artifacts: generated build outputs and dependency directories, only after repo/worktree review.
• User-facing files: Downloads/Documents/media, only with path-level approval.
• Browser/app support data: usually defer; browser profiles are not cache.

Proven High-Dividend Pattern

On a near-full Mac, this approved batch reclaimed meaningful space:

docker system prune -af
rm -rf "$HOME/Library/Developer/Xcode/DerivedData"/*
rm -rf "$HOME/Library/Logs/activitywatch"

Important constraints:

• Do not add --volumes to Docker prune unless the user explicitly approves volume deletion.
• docker system prune -af removes stopped containers, unused networks, unused images, and build cache; images may need rebuild or re-pull later.
• Xcode DerivedData is generated build data and will be recreated.
• Running apps may recreate log directories during deletion; verify final size rather than treating a tiny leftover log directory as failure.

Verification

After each approved batch:

df -h / /System/Volumes/Data
du -sh <approved-targets> 2>&1
docker system df 2>&1

Record:

• before and after free-space numbers
• command transcript
• target sizes before/after
• nonzero exit statuses and whether they are material
• skipped/deferred items
• recovery notes, such as "rebuild Docker image" or "Xcode will recreate DerivedData"

For tracked tasks, update status.md, save curated summaries under task-progress-artifacts/, and keep raw logs in task-progress-artifacts/scratchpad/.