Audit a skill with Skill Crossroads

Grade the target skill and report every finding evidence-cited (file and line) — work from the receipts, not vibes. Only when the user asks for fixes, apply the highest-impact ones and re-grade until the score stops improving.

Overview

Most skills fail silently: they never trigger, over-grant tools, or leak secrets, and the author only finds out after publishing. This skill closes that loop before you ship. It runs the free skillcrossroads CLI (MIT) against a skill directory, producing a letter grade, a file:line-cited scorecard across six rubric categories, and a ranked fix list. Auditing is read-only; when the user also wants the skill improved, it walks that list, applying the smallest change that resolves each finding, until the grade stops improving.

Prerequisites

• Node.js 20+ with npx available, and network access to the npm registry (the CLI is fetched on demand; the version is pinned below for reproducibility).
• A skill directory containing a SKILL.md file.
• No credential is required, and by default nothing about your skill leaves the machine. Every command in this skill passes --no-llm, so all six rubric categories are scored deterministically and locally.
• The one exception is --suggest in step 4, which is opt-in and requires your explicit consent. Without --no-llm, the CLI sends content to Anthropic's Messages API (api.anthropic.com) whenever ANTHROPIC_API_KEY is present in the environment — it does not prompt. That path upgrades the Triggering category to an LLM judge and adds checks VERIFY-04, CLARITY-02 and CLARITY-05, sending per-check excerpts of 1,500-2,500 characters; --suggest sends up to 24,000 characters of the entry file. Requests are billed to your own key. Treat the key as a credential: never echo or commit it.
• Model results are cached on disk between runs, keyed by content hash: ./.beacon-cache if that directory already exists, otherwise %LOCALAPPDATA%\skillcrossroads\cache on Windows, $XDG_CACHE_HOME/skillcrossroads when set, or ~/.cache/skillcrossroads.

Steps

1. Identify the skill directory (it contains a SKILL.md). Use Glob to find **/SKILL.md candidates or Grep to search for the skill by name. If more than one candidate exists, ask the user which skill to audit.
2. Run the audit and capture the report. Single-quote the directory argument — single quotes prevent the shell from expanding $(...), backticks, and $variables hidden in a path (double quotes do NOT stop command substitution). Before running, inspect the path: if it contains a single quote, $, a backtick, or a newline, do not pass it to a shell at all — such characters in a skill directory name are themselves a red flag; rename the directory or ask the user for a safe path first.

   npx skillcrossroads@0.11.4 '<skill-dir>' --no-llm --markdown

1. Report the scorecard and the Top fixes list (ranked by grade impact) to the user. Auditing is read-only. If the user asked only to audit, grade, check, or lint, stop here — do not edit anything. Proceed to step 4 only when the user explicitly asked to fix or improve the skill, or confirms they want the fixes applied after seeing the report.
2. Apply fixes (only on explicit request or confirmation). The deterministic report from step 2 is normally enough to work from.

Optionally, model-drafted rewrites are available — but --suggest is the only command in this skill that sends anything off the machine, so ask the user before running it and proceed only on an explicit yes:

> --suggest sends up to 24,000 characters of this skill's entry file to Anthropic's API > (api.anthropic.com), billed to your own ANTHROPIC_API_KEY, and caches the result on > disk. Run it, or continue with the local findings?

On a yes, and only when ANTHROPIC_API_KEY is set:

   npx skillcrossroads@0.11.4 '<skill-dir>' --suggest

If the user declines, or no key is set, continue with the step 2 findings — they already cover all six rubric categories. Either way, treat suggestions as proposals to review and never apply one unread. For each fix, Read the cited file:line, confirm the finding is real, and apply the smallest Edit that resolves it. Typical high-impact fixes: rewrite the frontmatter description to lead with the use case and include the phrases a user would actually say; add a verification step; state constraints and failure modes; remove hardcoded secrets or over-broad allowed-tools.

1. Re-run the audit. Repeat steps 4–5 until the grade stops improving or only intentional trade-offs remain.
2. Offer the badge: npx skillcrossroads@0.11.4 '<skill-dir>' --no-llm --badge writes an SVG the user can embed in their README, linking to https://skillcrossroads.com for the hosted version. It lands in the current working directory as <name>.beacon.svg, not inside the skill directory; pass --badge=<path> to choose where it goes.

Output

• A markdown scorecard: overall letter grade, per-category scores across the six rubric categories, and every finding cited with file and line.
• A ranked Top fixes list ordered by grade impact.
• After the fix loop (when the user requested fixes): the before → after grades, reported to the user.
• With --badge: an SVG badge file, <name>.beacon.svg, written to the current working directory — not into the skill directory; --badge=<path> chooses another location.

Error Handling

• If npx fails (offline, registry blocked, unsupported Node version), report the error verbatim and stop — do not hand-estimate a grade.
• If no SKILL.md is found in the target directory, ask the user for the correct path instead of guessing.
• If the grade plateaus with findings remaining, list each residual finding and ask the user whether it is an intentional trade-off; never mask a finding to force a grade.
• Never suppress, delete, or work around a SAFETY-* finding — fix the underlying problem (remove the secret, narrow the tool grant). Safety findings always count.
• Do not pad the skill with filler to game a check; if a finding is a deliberate trade-off, say so to the user instead of masking it.
• Say which mode ran (keyless deterministic vs. LLM-upgraded) so the user knows what the grade covers.

Examples

User: "Audit my skill in skills/deploy-checker — why doesn't it trigger?"

npx skillcrossroads@0.11.4 'skills/deploy-checker' --no-llm --markdown

The report grades Triggering low, citing SKILL.md:3 — the description lacks the phrases a user would say. Report that finding and stop (the user asked why, not for edits). If they then say "fix it", rewrite the description to lead with the use case, re-run the audit, and report the before → after grade (for example C → A). Alternatively, run with --suggest to review proposed rewrites before applying them.

Verify

Done means: for an audit-only request, the scorecard and Top fixes list were reported with no files modified. For a fix request: the final npx skillcrossroads@0.11.4 '<skill-dir>' --no-llm --markdown run shows the improved grade with no fail-status findings remaining (or each remaining one acknowledged by the user as intentional), and the before → after grades are reported to the user.

Resources

• references/rubric-categories.md — the six rubric categories, their weights, and keyless vs. LLM-upgraded coverage.
• references/flags-quick-reference.md — --markdown / --suggest / --badge / --min-grade at a glance.
• skillcrossroads on npm — the CLI this skill runs (pinned to 0.11.4).
• skillcrossroads.com — hosted scans, badges, and per-check fix documentation.
• Check reference — what every rubric check measures and how to fix it.
• Source repository — plugin/ there is the canonical copy; the marketplace entry is a mirror of it, so fixes land upstream first.