# Usage > Survey disk usage across every filesystem layer and classify what is reclaimable, without deleting anything - Skill: `tony/usage` (Agent Skill) - Install (CLI): `npx skillmds@latest add tony/usage` - Raw SKILL.md: https://api.skillmd.com/api/skills/tony/usage/raw - Safety review: pending - Works with: Claude Code, Claude.ai, OpenAI Codex - Category: Coding & Dev Tools - Author: tony (https://skillmd.com/u/tony) - Updated: 2026-09-17 - Page: https://skillmd.com/skills/tony/usage --- Survey this machine's disk usage and report where the space went. Scope: $ARGUMENTS — when empty, survey every mounted filesystem. This command is read-only. Do not delete, move, compress, or modify anything. Do not halt a virtual machine or WSL guest under any circumstance. Produce an analysis the user can act on, and end by offering `/disk:reclaim`. ## Establish the layer structure Read `../../references/virtual-disks.md` first. Run `df -h` and identify every distinct filesystem with its used and available space. Determine which of them is the binding constraint — the one closest to full — because that governs which findings matter. When a filesystem is a virtual disk, find its backing file on the host and compare that file's allocated size against the used space reported inside the guest. The gap is balloon: space recoverable by compaction alone, without deleting anything. Report it as a distinct figure. Check whether the guest issues TRIM, so the report can explain whether balloon will keep re-accumulating. ## Measure Survey each filesystem separately. Prefer `dust` with an explicit depth and minimum size, falling back to `du` when unavailable. Set the minimum size relative to the filesystem rather than using a fixed value, so a small disk still produces findings and a large one is not drowned in them. Around one percent of total capacity works. Resolve symlinks before recording a size. Configuration directories managed by a dotfiles repository routinely appear under two paths, and counting both inflates the total while implying a duplicate that does not exist. ## Classify Assign every candidate to a tier from `../../references/candidate-catalog.md`. Classify at the level where content is homogeneous — a protected history root frequently contains regenerable build artifacts, and those are separable. For anything holding agent transcripts or session data, read `../../references/agent-history.md`. Identify each tool's discovery glob, whether it maintains a state database, and whether it supports compressing its own history natively. Report what is protected and why; propose nothing destructive here. For candidates that look like duplicates, run the path-set comparison in `../../references/redundancy-proofs.md` and record the outcome as redundant, mergeable, conflicted, or unique. A directory named like a backup is not a backup until the proof says so — and a `diff` reporting no differing files proves nothing on its own. For directories of upstream clones kept for reading, read `../../references/study-repos.md`. Report huge clones, clones that are not shallow, and build artifacts as three separate groups, and check each clone for unpushed work before calling it a conversion candidate. ## Output Follow `../../references/output-contract.md`. Lead with the binding constraint in one line. An inventory of large directories does not answer "where did my space go" when the real limit is a different layer the user has not looked at.