Conciseness

The body is mostly lean and operational, but the 'Key facts' section restates five points already made verbatim-earlier ('check with `command -v devbox` and install via curl', 'devbox.json may live in the repo root or a subdir root', 'Prefer `devbox run` over `devbox shell`', 'first run ... can be slow'). That duplication is more than 'minor instances that could be trimmed', so it fits the 3 anchor rather than 4; it is not a 2 because no space is spent explaining concepts Claude already knows.

Actionability

Every section gives copy-paste-ready commands: `command -v devbox`, the curl install one-liner, `ls devbox.json 2>/dev/null || find . -maxdepth 2 -name devbox.json`, `devbox run psql "$MASTER_DB_URL" -c 'SHOW wal_level;'`, `devbox search`/`devbox add`, and `devbox services ls/up/stop`. The examples cover the common cases with real invocations, matching the 5 anchor.

Workflow Clarity

There is a clear implicit sequence (detect devbox.json → check installed → install with error recovery for PATH → run) and a numbered decision list for binary sourcing with a `devbox search` checkpoint and a user-confirmation gate before `devbox add`. It is a 4 rather than 5 because the steps are spread across sections with no single end-to-end sequence and some checkpoints (e.g. confirming devbox.json exists before running) are implicit; it is above 3 because checkpoints and error-recovery guidance are present.

Progressive Disclosure

The body is well-organized into clearly signaled sections (When to reach for it, Check it's installed, How to run, Project scripts, Services, Discovering more) with no bundle files, so nothing is buried or nested. It scores 4 rather than 5 because at ~119 lines it exceeds the simple-skill threshold and carries the duplicated 'Key facts' section that should either be merged into the body or split out — a minor organization gap, not the structural problems of a 3.

Specificity

The description names concrete actions ('Run commands inside a devbox environment', 'prefer it over the system binary') and concrete tools ('psql, python, gcloud, node'), but coverage is incomplete — package installation, project scripts, and services are unmentioned. It lists several specific actions with minor gaps, matching the 4 anchor rather than the comprehensive 5.

Completeness

It explicitly answers both 'what' ('Run commands inside a devbox environment when a directory provides one') and 'when' ('If a `devbox.json` exists in the current directory (or an ancestor/subdir root)') with a concrete trigger phrase. The 'when' is an explicit conditional rather than weakly implied, matching the 5 anchor and not the 4.

Trigger Term Quality

Natural trigger terms are present: 'devbox', '`devbox.json`', 'environment', and the tool names a user would mention. A few natural synonyms/variants (e.g. 'nix', 'jetify') are missing, which fits the 4 anchor (good coverage, a few terms missing) rather than the comprehensive 5.

Distinctiveness Conflict Risk

'devbox' is a unique, specific niche trigger tied to a concrete file ('devbox.json'), with minimal overlap risk against any other skill. This matches the 5 anchor (clear niche with distinct triggers); the 4 anchor would require some overlap with closely related skills, which is not the case.