Conciseness

The body is lean with zero padding: 'This destroys containers, images, volumes, and networks. Any stopped container will be wiped and data will be lost.' plus a single command, a four-item deletion list, and four one-line use cases. It explains nothing Claude already knows and every token earns its place — a clean match for anchor 5.

Actionability

The guidance is a fully executable, copy-paste-ready command ('```bash /workspaces/NetAlertX/.devcontainer/scripts/confirm-docker-prune.sh ```') that covers the single common case completely, matching the anchor-5 'copy-paste ready commands' example. Not 4 because there are no gaps for this one-task skill — the command is exact and absolute.

Workflow Clarity

The operation is destructive and destructive/batch skills without validation steps are capped at 3, taking precedence over the simple-skill exception. The content only states 'The script requires explicit confirmation before proceeding' — no verify-before/after step, no dry-run, no post-check (e.g. confirm free disk space), which lands on anchor 3 ('sequence present but checkpoints missing or implicit'). Not 2 because the sequence is unambiguous and the confirmation gate is at least named; not 4 because no verification content exists in the body.

Progressive Disclosure

This is an under-50-line single-task skill with no external references needed, and the sections (DANGER, Command, What Gets Deleted, When to Use, Safety) are well-organized and easy to navigate — the rubric's stated condition for a 5 in this case. No bundle files exist (no references/, scripts/, or assets/ directories), so nothing is inappropriately inlined or buried.

Specificity

The description names the domain and one action ('Clean up unused Docker resources') but the 'what' is generic — it never enumerates the concrete operations (pruning containers, images, volumes, networks) that the body lists. Anchor 3 ('names domain and 1-2 concrete actions, but not comprehensive') fits; it is above 2 because Docker plus cleanup is concrete, and below 4 because no multi-action enumeration exists.

Completeness

Both parts are present: 'what' ('Clean up unused Docker resources') and an explicit 'when' ('Use this when asked to prune docker, clean docker, remove unused images, free disk space, or docker cleanup'). Not 5 because the 'what' is a single generic clause rather than the concrete action enumeration of the anchor-5 example, though the 'when' itself is explicit with concrete triggers.

Trigger Term Quality

Quotes natural user phrasings: 'prune docker, clean docker, remove unused images, free disk space, or docker cleanup' — good keyword coverage of how a user would actually ask. Not 5: common variations like 'docker system prune', 'reclaim disk space', or 'delete old images' are missing.

Distinctiveness Conflict Risk

The docker-prune niche is distinct with dedicated triggers ('prune docker', 'docker cleanup'). Not 5 because 'free disk space' is a broad trigger that could also fire general disk-cleanup skills; not 3 because the dominant triggers are unambiguously docker-scoped.