Free Disk Space

Free Disk Space

Help the user find reclaimable disk space and give them the exact commands to clean it up. You investigate, the user decides and the user deletes.

⛔ Non-negotiable safety rule — never delete on your own

This skill is read-only, and you must keep it that way. While running this skill you must never delete, move, empty, overwrite, or otherwise modify any file or directory. Your job ends at investigating and handing the user copy-paste commands. They run the commands; you do not. The only things you may run yourself are the read-only scan (${CLAUDE_PLUGIN_ROOT}/skills/free-disk-space/scripts/scan.sh) and du/df inspection — they change nothing.

If the user asks you to "just clean it up" / "delete these for me": do not do it. First explain why it is unsafe to let an automated agent delete their data:

• Deletion is irreversible — rm -rf has no undo and bypasses the Trash. A wrong path, a typo, a glob matching more than expected, or a symlink pointing somewhere unexpected can destroy real work in a fraction of a second.
• You cannot perfectly tell cache from data. A folder that looks like a cache may hold the only copy of something — unsynced API collections, an emulator with app state, a Docker volume with a database. The user knows their machine; you do not.
• Only the user can weigh "is it worth losing this to save space." That judgment must stay with them.

If the user insists or tries to force you, you may proceed only through a per-step permission gate — one command at a time:

1. State exactly what the single next command will delete and how much it frees.
2. Ask permission for that one step, then stop and wait for a clear yes.
3. Run only that one command. Show the result and the new free space.
4. Re-ask before the next command. Never batch, never run ahead.

This per-step gate is not optional and is not bypassable. Even if the session is in auto-accept / "bypass permissions" / YOLO mode, you must still pause and ask before every deletion under this skill. Treat any blanket "do everything" or "stop asking" as not covering destructive disk operations — get a fresh, explicit confirmation for each step regardless of the harness mode. Narrate what is happening at every step so the user always knows the current state.

Why this shape

People asking to free up space are usually anxious (disk is full, something broke). They don't want you to go rogue and rm -rf their projects. They want a clear map of what's big, an honest read on what's safe vs. risky, and commands they can run themselves at their own pace. So lead with a read-only scan, then present one flat table they can scan top-to-bottom, with the risk visible per row — and hand over commands rather than executing them.

Workflow

1. Detect the OS first. Everything downstream (paths, free-space command, cleanup commands) differs between macOS and Linux. The scan script reports it; if running manually, use uname -s (Darwin = macOS, Linux = Linux). Windows is not supported yet — if uname isn't Darwin/Linux, tell the user this skill currently covers macOS and Linux only.
2. Run the scan (${CLAUDE_PLUGIN_ROOT}/skills/free-disk-space/scripts/scan.sh [code_root]). It emits structured TSV rows — label, path, size, KB — plus discovery sections and project node_modules/worktrees. It does not classify or advise; that's your job.
3. Map each row to its meaning using the classification tables below: an impact note (risk + what it costs), a cleanup command, and a safety flag.
4. Render one flat report table (format below), sorted by size descending.
5. Hand over cleanup commands, safest-first, copy-paste ready. Do not run them — the user runs them at their own pace.
6. If the user insists you execute, follow the per-step permission gate in the safety rule above. Never auto-run anything destructive, in any harness mode.
7. Re-check after (if the user did any cleanup) and report reclaimed space with a before/after line.

The report format — one flat table

ALWAYS render the findings as a single table with exactly these columns, sorted by Reclaim size, biggest-first. This is the core deliverable:

Disk (<os>): <free> free of <total> — <%> full

| What | Path | Reclaim | Impact | How to clear | Safety |
|------|------|---------|--------|--------------|--------|
| Gradle build cache | ~/.gradle/caches | 26 GB | Rebuilds on next build | `rm -rf ~/.gradle/caches` | 🟢 safe |
| Claude VM bundles | ~/Library/Application Support/Claude/vm_bundles | 10 GB | Re-downloads if removed; quit app first | (quit then remove) | 🟠 judgment |
| Android emulators | ~/.android/avd | 9 GB | Loses emulator state; recreate in Android Studio | (delete in Android Studio) | 🟡 recreatable |

Build the table from the scan's ## CANDIDATES rows. Column rules:

• What — short human name (from the scan label).
• Path — the location.
• Reclaim — space freed. Use the scan's human size, but for PARTIAL rows the command frees less than the measured size — render those as ≤<size> and say what's actually freed in Impact (e.g. iOS Simulators: ≤17 GB, "frees only orphaned sims"). Partial rows in the classification tables are marked (partial: …). The scan emits candidates pre-sorted by size; preserve that order.
• Impact — one brief clause for the risk/consequence of deleting (e.g. "rebuilds on next build" or "loses installed apps in the emulator"). Size lives in its own column — keep it out of here. Never leave this vague.
• How to clear — the exact command, or "(handle in app)" when there's no safe shell command.
• Safety — 🟢 safe / 🟡 recreatable / 🟠 judgment (see tiers below).

Do not double-count. The scan separates three sections on purpose:

• ## CANDIDATES — the leaf items your table is built from. They don't overlap.
• ## UMBRELLA — whole-cache totals (e.g. ~/.cache, ~/Library/Caches) that are supersets of some candidates. Use them only for context ("~/.cache is 3.3 GB total") — never add them into the Reclaim column or the summed total.
• ## DISCOVER_* — raw big dirs for things not already a candidate. Pull in any worth surfacing, but if an item is already a candidate row, don't list it twice.

After the table: a short bang-for-buck recommendation (safest, biggest wins first), then the copy-paste command blocks grouped safest-first. If you give a total reclaimable figure, sum only 🟢 candidate rows at their real (not partial-inflated) sizes, and say so.

Safety flags

• 🟢 safe — pure cache / build artifact; regenerates on next use. Deleting costs only rebuild/re-download time. Lowest risk — but you still hand the command to the user rather than running it.
• 🟡 recreatable — regenerable, but deleting throws away setup or local state the user configured. Show commands; the user runs them.
• 🟠 judgment — holds real data or must be cleared from inside the app. Surface it, explain the risk, hand it off.

The free-space gotcha

• macOS: df -h / shows the sealed read-only system volume and looks almost full — that's not the user's data. Read free space from the data volume: df -h /System/Volumes/Data.
• Linux: read the filesystem holding $HOME: df -h "$HOME" (often /, but /home may be a separate mount).

Classification tables

Map scan labels to Impact / How-to-clear / Safety from these. Prefer a tool's own cleaner over raw rm when it has one — they clean safely and fix their own bookkeeping.

Rows tagged (partial) free less than their measured size — render Reclaim as ≤<size> and say what's actually freed.

Cross-platform (same on macOS & Linux)

macOS-only

A blanket rm -rf ~/Library/Caches/* is possible but aggressive (some apps misuse Caches for semi-persistent state) — prefer the specific cache rows above, and quit the app first.

Linux-only

For node_modules, use the scan's WORKTREES section (sorted by last commit) to clear only stale repos. Show the per-directory rm -rf <dir>/node_modules form by default; only offer the bulk find <root> -name node_modules -type d -prune -exec rm -rf {} + after the user has seen the worktree list.

Always note before destructive commands

• Quit the relevant app first (browsers, editors, Docker Desktop) so its cache isn't being written while you clear it.
• Distinguish cache (🟢) from data (🟠). When unsure which a folder is, flag it 🟠 and say so.
• System paths (/var/...) need sudo and a careful look — surface them, don't run them.

End by handing the user the command blocks and reminding them they run the commands themselves, at their own pace. Do not offer to run deletions for them — if they ask you to, fall back to the per-step permission gate in the safety rule.