config-gc

Config GC — Garbage Collection for Claude Code Setups

Borrowed from runtime garbage collection: periodically scan for objects that are no longer referenced, redundant, expired, or low-value, and reclaim the space. The critical difference: here, collection requires a human in the loop. Never delete autonomously.

When to Activate

• The user asks to clean up, audit, or slim down their Claude Code configuration
• The user complains about too many skills, noisy hooks, or slow session startup
• A monthly/periodic config review is due
• After installing a large skill pack (e.g. this repo), to reconcile overlaps with existing setup

Do NOT activate for: cleaning project source code (that's refactoring), clearing chat history, or uninstalling Claude Code itself.

Design Philosophy

1. Append-only configs leak. Skills, memory files, hooks, and permission entries only ever get added. Without periodic review they rot silently.
2. Regular audits beat one-time purges. Scan every ~30 days, propose a small batch of candidates each time.
3. Per-channel strategies. Each accumulation type (skills, hooks, permissions, ...) has its own staleness signals — don't apply one rule everywhere.
4. Soft-delete first. Rename to .disabled > move to ~/.claude/_gc_trash/ > real deletion. Always keep an undo path.
5. Forced human-in-the-loop. Every candidate gets its own [y/n/skip] confirmation. No "yes to all" shortcut.
6. Keep a log. Every GC run appends to ~/.claude/gc_log.md: what was touched, why, and how to undo it.

Scan Channels

Workflow

1. Scan all channels (or the subset the user names). Collect candidates with: path, channel, signal that flagged it, size, last-modified.
2. Rank by confidence (broken/orphaned = high; merely old = low) and present as a numbered table. Cap each run at ~20 candidates — GC is periodic, not exhaustive.
3. Confirm one by one. For each candidate show the evidence, then ask [y/n/skip]. The user can stop at any point.
4. Soft-delete confirmed items: prefer .disabled rename for skills/hooks and _gc_trash/<date>/ move for files. Permission entries live in JSON (no comments possible): back up the settings file, record each removed entry verbatim in gc_log.md, then remove it from the allow array with jq. Only hard-delete when the user explicitly asks.
5. Log the run to ~/.claude/gc_log.md: timestamp, items actioned, undo instructions.
6. Report: reclaimed size, channels still healthy, suggested next review date.

Example Scan Commands

Orphaned hook scripts (channel 3) — scripts on disk that no hook config references:

for f in ~/.claude/hooks/*; do
  name=$(basename "$f")
  grep -rq "$name" ~/.claude/settings.json ~/.claude/settings.local.json 2>/dev/null \
    || echo "ORPHAN: $f"
done

Redundant permission entries (channel 4) — duplicates, and specific grants shadowed by a wildcard:

jq -r '.permissions.allow[]' ~/.claude/settings.local.json | sort | uniq -d
if jq -e '.permissions.allow | index("Bash(*)")' ~/.claude/settings.local.json >/dev/null; then
  jq -r '.permissions.allow[]' ~/.claude/settings.local.json \
    | grep '^Bash(' | grep -vF 'Bash(*)'
fi

Largest stale caches (channel 8) — du -k instead of GNU-only find -printf, so it works on macOS/BSD too:

find ~/.claude/file-history ~/.claude/shell-snapshots -type f -mtime +30 \
  -exec du -k {} + 2>/dev/null | sort -rn | head -20

Soft-delete with undo path (capture the date once so the log can't disagree with the directory):

gc_date=$(date +%Y-%m-%d)
mkdir -p ~/.claude/_gc_trash/$gc_date
mv ~/.claude/skills/dead-skill ~/.claude/_gc_trash/$gc_date/
echo "$(date -Iseconds) moved skills/dead-skill -> _gc_trash/$gc_date/ (undo: mv back)" >> ~/.claude/gc_log.md

Removing a confirmed-redundant permission entry (JSON has no comments — back up, log, then edit):

cp ~/.claude/settings.local.json ~/.claude/settings.local.json.bak
echo "$(date -Iseconds) removed permission entry: Bash(git push) (undo: restore from .bak or re-add)" >> ~/.claude/gc_log.md
jq '.permissions.allow -= ["Bash(git push)"]' ~/.claude/settings.local.json.bak \
  > ~/.claude/settings.local.json

Anti-Patterns

• Bulk approval. Asking "delete all 15? [y/n]" defeats the design. One item, one decision.
• Hard-deleting on first pass. If there's no _gc_trash/ copy or .disabled rename, you did it wrong.
• Treating "old" as "dead". A skill untouched for 60 days may be seasonal (tax season, quarterly reviews). Age is a signal, not a verdict — that's why a human confirms.
• Cleaning memory by truncation. Merging two contradicting memory files requires reading both and keeping the newer truth, not deleting the longer one.
• Touching anything outside `~/.claude` (or the project's .claude/). Config GC never wanders into source trees.

Best Practices

• Run after big additions, not just on a calendar: installing a 50-skill pack is exactly when overlap with existing skills appears.
• When two skills overlap, prefer disabling the one with the weaker trigger description — it's the one that was probably never firing anyway.
• Permission cleanup is the highest-value channel per minute spent: redundant allow-entries make security review harder.
• Keep gc_log.md forever. It's tiny, and "when did I disable that hook and why" comes up more often than you'd think.

Related Skills

• skill-stocktake — audits skill quality; config-gc audits skill existence. Run stocktake on what survives GC.
• workspace-surface-audit — the additive counterpart: recommends what to install. config-gc is the subtractive half of the same lifecycle.
• configure-ecc — after installing skills with it, run config-gc to reconcile overlaps with your pre-existing setup.
• continuous-learning — produces the memory files this skill later audits.
• security-review — pairs well with the permissions channel.