ctx-skill-audit

name	ctx-skill-audit
description	Audit skills against Anthropic prompting best practices. Use when reviewing skill quality, after creating or modifying a skill, before releasing skills, or when a skill produces inconsistent results. Also use when the user says 'audit this skill', 'check skill quality', 'review the skills', or 'are our skills any good?'

Audit one or more skills against Anthropic's prompting best practices. The goal is to find patterns that degrade skill effectiveness with current Claude models and suggest concrete improvements.

When to Use

• After creating or modifying a skill (quality gate)
• Reviewing all skills before a release (batch audit)
• When a skill produces inconsistent or poor results
• When skills were written for older models and may need calibration for Claude 4.5/4.6

Before Auditing

1. Read references/anthropic-best-practices.md from this skill's directory: it contains the condensed audit criteria.
2. Identify which skill(s) to audit. If the user names a specific skill, audit that one. If they say "audit all skills," plan a batch pass.
3. For bundled skills, read from internal/assets/claude/skills/*/SKILL.md. For live skills, read from .claude/skills/*/SKILL.md.

Audit Dimensions

Apply these checks to each skill. Each dimension maps to a section in the best practices reference.

1. Positive Framing

Scan for negative instructions ("don't", "never", "avoid", "do not") that lack a positive counterpart. Every negative should be paired with what the agent should do instead.

Pass: negative instructions are supplements to clear positive guidance. Fail: primary instructions are negative, leaving the agent to guess the desired behavior.

Do not create new files. Do not modify tests. Do not add comments. Edit only the files specified in the task. Preserve existing tests and comments: add new ones only when the user requests them.

2. Motivation Over Mandates

Check for MUST, NEVER, ALWAYS, CRITICAL used as emphasis without explaining why the rule matters. Claude 4.5/4.6 responds better to reasoning than rigid directives.

Pass: important instructions include motivation ("because X" or "so that Y") that lets the model generalize. Fail: instructions rely on emphasis alone to convey importance.

You MUST ALWAYS run tests before reporting completion. Run tests before reporting completion: untested changes create silent regressions that compound across sessions.

3. XML Tag Structure

Check whether the skill mixes instructions with variable content (file paths, user input, injected code) without clear delimiters. XML tags prevent the model from confusing injected content with skill instructions.

Pass: variable content is wrapped in descriptive tags, or the skill doesn't inject variable content. Fail: the skill templates in external content alongside instructions without delimiters.

4. Few-Shot Examples

Check whether non-trivial behaviors (output formats, decision logic, style requirements) are demonstrated with examples. Skills that describe complex output without showing it drift over time.

Pass: key behaviors have at least one good/bad example pair, or the behavior is simple enough that examples would be redundant. Fail: the skill describes a specific output format or decision process but provides no examples.

5. Subagent Guard

If the skill spawns or encourages spawning subagents (via the Agent tool), check that it states when subagents are and aren't warranted. Claude Opus 4.6 over-delegates to subagents when a direct tool call would be faster.

Pass: subagent usage has explicit scope (when to use, when not to), or the skill doesn't involve subagents. Fail: the skill defaults to subagent delegation without stating when direct execution is preferable.

6. Overtriggering Calibration

Check for language written to combat undertriggering in older models that may cause overtriggering in Claude 4.5/4.6: excessive caps emphasis (CRITICAL, MUST), redundant capability statements ("You are an expert"), or aggressive always/never framing.

Pass: instructions use natural language with emphasis reserved for genuinely critical points. Fail: the skill reads like it was written for a less capable model that needed constant nudging.

7. Phantom References

Every file path, tool name, and command referenced in the skill must exist. Broken references are a form of hallucination in the skill itself.

Pass: all references resolve to real files/tools. Fail: the skill mentions files or commands that don't exist.

8. Scope Discipline

Check whether the skill encourages work beyond what's requested: "while you're in there" improvements, unsolicited refactoring, or scope creep. Skills should state the minimum viable outcome.

Pass: the skill's scope matches its stated purpose. Fail: the skill encourages additional work beyond its core task.

9. Description Trigger Quality

The description field determines when the skill activates. Check that it:

• Covers concrete trigger situations and user phrases
• Includes synonyms and related concepts
• Is specific enough to avoid false triggers
• Is "pushy" enough to avoid undertriggering

Pass: reading the description alone, you'd know exactly when to use this skill. Fail: the description is vague ("use for general tasks") or too narrow (misses common phrasings).

Process

Single Skill Audit

1. Read the skill's SKILL.md.
2. Apply all 9 audit dimensions.
3. Report findings using the output format below.
4. Suggest specific rewrites for any failures: show the current text and the proposed replacement.

Batch Audit

1. List all skills to audit (bundled, live, or both).
2. Audit each skill directly in the main conversation: spawning one subagent per skill adds latency and context overhead that outweighs parallelism for typical batch sizes.
3. Report concisely: only dimensions that fail or have notable findings.
4. Summarize with a scorecard at the end.

Output Format

For each audited skill, report:

### /skill-name

**Overall:** X/9 pass

| # | Dimension              | Result | Notes                    |
|---|------------------------|--------|--------------------------|
| 1 | Positive framing       | pass   |                          |
| 2 | Motivation over mandates | fail | 3 bare MUST/NEVER found  |
| 3 | XML tag structure      | pass   |                          |
| 4 | Few-shot examples      | fail   | No output format example |
| 5 | Subagent guard         | n/a    | No subagent usage        |
| 6 | Overtriggering         | pass   |                          |
| 7 | Phantom references     | pass   |                          |
| 8 | Scope discipline       | pass   |                          |
| 9 | Description quality    | warn   | Missing synonym coverage |

**Suggested fixes:**
- [Dimension 2] Line "You MUST ALWAYS run tests" →
  "Run tests before completion: untested changes create
  silent regressions."
- [Dimension 4] Add example showing expected output format
  after the "Report results" section.

For batch audits, end with a summary:

## Batch Summary

| Skill              | Score | Top Issue                |
|--------------------|-------|--------------------------|
| ctx-commit         | 8/9   | Missing example          |
| ctx-drift          | 7/9   | 2 bare mandates          |
| ctx-verify         | 9/9   | -                        |

Quality Checklist

Before reporting audit results:

• Read the best practices reference before starting
• Applied all 9 dimensions (mark n/a where inapplicable)
• Every "fail" has a specific suggested rewrite, not just a description of the problem
• Phantom reference check actually verified file existence (used Glob/Read, not assumption)
• Description quality check considered real user phrases, not hypothetical ones