# Disk Pressure Proactive

> In a disk-constrained environment, proactively prune caches and build output for headroom *before* operations fail, while foreground work continues in parallel. State the safety property of each prune so the user trusts it without a confirm. Use when disk free space is low (~<2-3 GB), when heavy installs/builds are incoming, or in repos with a known disk blocker (BLK-DISK).

- Skill: `jcdavis131/disk-pressure-proactive` (Agent Skill)
- Install (CLI): `npx skillmds@latest add jcdavis131/disk-pressure-proactive`
- Raw SKILL.md: https://api.skillmd.com/api/skills/jcdavis131/disk-pressure-proactive/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Coding & Dev Tools
- Author: jcdavis131 (https://skillmd.com/u/jcdavis131)
- Updated: 2026-09-21
- Page: https://skillmd.com/skills/jcdavis131/disk-pressure-proactive

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# Disk Pressure Proactive

In a constrained-disk environment, installs fail mid-flight and leave broken state. Pruning *before* the failure is cheaper than recovering after. And the prune runs in parallel with foreground work — disk-headroom work doesn't block feature work.

## The trigger

Check free space at session start (see `session-orient`) and before any heavy install/build:

```powershell
Get-PSDrive C | Select-Object Used,Free
```

If free space is under ~2-3 GB, or a heavy install/build is incoming and space is under ~5 GB, prune proactively. Don't wait for the ENOSPC failure.

## The prune cascade (priority order)

Hit the cheap wins first, measure before deleting, bound the recursion:

1. **Recycle Bin** — `Clear-RecycleBin -Force -ErrorAction SilentlyContinue`. Always safe; often a few hundred MB.
2. **Build output dirs** — bounded recursion, measure, delete:
   ```powershell
   $dirs = Get-ChildItem apps -Recurse -Directory -Filter ".next" -Depth 3 -ErrorAction SilentlyContinue
   $dirs | ForEach-Object { "{0:N0} MB {1}" -f ((Get-ChildItem $_.FullName -Recurse -File -EA SilentlyContinue | Measure-Object Length -Sum).Sum / 1MB), $_.FullName }
   # then delete the confirmed ones
   ```
   `-Depth 3` bounds the scan so it doesn't cost more than the reclaim. Targets: `.next/`, `dist/`, `build/`, `.output/`, `.turbo/`, `.vercel/`.
3. **Package store (unreferenced only)** — `pnpm store prune`, `uv cache clean`. Safe — removes only unreferenced packages.
4. **Temp** — `Remove-Item $env:TEMP\* -Recurse -Force -EA SilentlyContinue` (selective; don't nuke files in use).

## State the safety property before each prune

A prune sounds destructive. Name its safety property so the user trusts it without a confirm round-trip:

> "Pruning the pnpm store (safe, removes only unreferenced packages)."
> "Clearing the Recycle Bin (no project files there)."

If a prune is *not* safe by default (e.g. deleting `.next/` while a dev server is running), say so and either skip it or stop the server first (see `shell-confirm-hygiene`).

## Run the prune in parallel with foreground work

The prune is disk-headroom work; it doesn't block feature work. While it runs, continue the foreground task ("pruning the uv cache for headroom while I build agentkit"). This is `fill-the-wait` applied to maintenance.

## When NOT to prune

- Free space is healthy (> ~5 GB and no heavy install incoming). Pruning then is churn.
- The prune target is in active use (a dev server writing to `.next/`). Stop the server or skip that target.
- The reclaim is smaller than the scan cost. Measure first; skip targets under ~50 MB.

## Anti-patterns

- **Waiting for ENOSPC.** Recovery from a half-installed package is harder than a prune.
- **`docker system prune -a` as the first move.** Nukes everything including images you wanted; targeted prunes first.
- **Unbounded recursion.** Scanning the whole tree costs more than the reclaim; use `-Depth`.
- **Pruning without stating safety.** Forces a confirm or a user "wait, is this safe?" — name the property.
- **Blocking feature work on the prune.** Run them in parallel.

## Pair with

- `session-orient` — the disk check at session start is the trigger source.
- `fill-the-wait` — the prune runs alongside the foreground task.
- `shell-confirm-hygiene` — a non-safe prune gets a confirm; a safe one says so and runs.
- `background-failure-triage` — if a prune fails, it doesn't abort the foreground build.