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create-skill

Scaffolds, diagnoses, and prunes agent skills. Modes: `scaffold` (default — runs the job once without a skill on a real input, records every correction, then writes a skill made of only those corrections), `diagnose` (retrospective failure analysis that emits a confidence-gated unified diff against any skill declaring a diagnostic surface), `prune` (deletes unused skills and trims or deletes those whose with/without-skill eval shows no lift over a same-length dummy). Triggers on "create a skill", "scaffold a skill", "new SKILL.md", "diagnose this skill", "why did the skill miss this", "prune my skills", "clean up my skills", "/create-skill".

Quality

91%

Does it follow best practices?

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SecuritybySnyk

Passed

No findings from the security scan

SKILL.md
Quality
Evals
Security

Quality

Content

85%Weight 40%Scale 1-5

Reviews the quality of instructions and guidance provided to agents. Good implementation is clear, handles edge cases, and produces reliable results.

The body is a dense, highly actionable multi-mode procedure with phased gates, validation scripts, feedback loops, and destructive-operation safeguards — near the top of the rubric for actionability and workflow clarity. Its main weaknesses are restating the same material across four sections (links, reading table, principles, definition of done) and a bundle that omits almost all of the `rules/` and `templates/` files the body depends on, breaking progressive disclosure in practice.

Suggestions

Ship the referenced bundle files: the body defers core procedure to `rules/run-first.md`, `rules/diagnose-mode.md`, `rules/prune-mode.md`, and `templates/SKILL.minimal.md`, none of which exist in the provided bundle — either include them or inline the minimal procedure for Phases 0–2 so the skill is self-sufficient.

Consolidate the four passes over the same content: the inline rule links, the "Required Reading by Phase" table, "Core Principles", and the "Definition of Done" checklists largely restate each other; keep one navigation map and one checklist and cut the rest to reclaim ~40 lines.

In "Phase 1 — Run", state what happens when the user rejects the output after several iterations (e.g. an escalation or stop condition), since the loop 'repeat until they accept it' is the only unbounded step in the scaffold workflow.

DimensionReasoningScore

Conciseness

Quotes: "Never add a step the agent did correctly in the run, a heading with no ledger row under it, or frontmatter the run did not need"; "Load these on demand — do not preload them all" — the body assumes Claude's competence and adds only skill-specific procedure, with compact ✗/✓ examples. Not 5: the same material is restated across passes — inline rule links, the "Required Reading by Phase" table, "Core Principles", and the "Definition of Done" checklists repeat the phase gates and run-first rationale, so several dozen lines could be trimmed. Not 3: there is no padding or explanation of concepts Claude already knows; the redundancy is navigational, not educational.

4 / 5

Actionability

Quotes: "Run `node ${CLAUDE_SKILL_DIR}/scripts/validate-skill.mjs <dir> [--portable]`"; "/create-skill diagnose <target-skill-name> [--symptom "..."] [--scope <phase|companion>] [--apply] [--pr] [--no-write]"; "Report `Verify: PASS — fresh run, 0 of <n> corrections recurred`"; the ledger path `.agent/{branch}/skill-run-<task-slug>.md` — commands, file paths, invocation syntax, and exact report lines are copy-paste ready, and the wrong/right dialogs give concrete behavioral contrasts. The instruction-only guidance is fully actionable without code.

5 / 5

Workflow Clarity

Quotes: the phased gate table ("Phase 1 — Run ... every correction is in the ledger — or the run was waived with a recorded reason"), "fix every `FAIL`, and report its `Self-check:` line verbatim", and "A recurring correction means the line meant to prevent it is wrong or missing: fix that line and re-run once" — explicit validation gates, feedback loops for error recovery, and per-mode checklists in the Definition of Done. Destructive operations are covered: prune requires "the user's explicit yes per skill before deleting or trimming anything" and caller migration, and diagnose's `--apply` is gated at "confidence(analysis) ≥ 90 %" with explicit confirmation before `git apply`, so the destructive/batch cap at 3 does not apply.

5 / 5

Progressive Disclosure

Quotes: "Detailed rules live in `rules/*.md` and templates in `templates/*.md`; load them on demand" and the "Required Reading by Phase" table — the body is designed for one-level-deep, clearly signaled, on-demand references. But scored against the actual bundle, only `references/run-first-rationale.md`, `references/lift-and-prune-rationale.md`, and `scripts/validate-skill.mjs` exist; the 16 referenced `rules/*.md` and `templates/*.md` paths (e.g. `rules/run-first.md`, which holds "The full procedure for Phases 0–2") are absent, so the disclosure chain cannot actually be followed. Not 4: missing the majority of referenced files is not a "minor organization gap"; not 2: the SKILL.md itself is well-structured and every reference is clearly signaled and correctly scoped, not buried or inlined.

3 / 5

Total

17

/

20

Passed

Description

100%Weight 40%Scale 1-5

Based on the skill's description, can an agent find and select it at the right time? Clear, specific descriptions lead to better discovery.

A model description: third person, states what it does for all three modes in concrete mechanical terms, and follows with an explicit trigger list of natural user phrasings covering each mode. It is dense but every clause carries information, so verbosity is not penalized.

DimensionReasoningScore

Specificity

Quotes: "runs the job once without a skill on a real input, records every correction, then writes a skill made of only those corrections"; "emits a confidence-gated unified diff against any skill declaring a diagnostic surface"; "deletes unused skills and trims or deletes those whose with/without-skill eval shows no lift over a same-length dummy" — every one of the three modes is unpacked into concrete, differentiated actions with comprehensive coverage. Not 4: there are no coverage gaps; each mode's mechanics are specified, not just named.

5 / 5

Completeness

What: "Scaffolds, diagnoses, and prunes agent skills" with per-mode elaboration; When: an explicit "Triggers on ..." clause enumerating eight concrete trigger phrases. Both questions are answered explicitly and concretely, so the 'missing when' cap at 3 does not apply. Not 4: the 'when' is not merely present — it is a dedicated, specific trigger list rather than a general 'Use when working with skills' clause.

5 / 5

Trigger Term Quality

Quotes: "create a skill", "scaffold a skill", "new SKILL.md", "diagnose this skill", "why did the skill miss this", "prune my skills", "clean up my skills", "/create-skill" — natural user phrasings with multiple synonyms per mode plus the file name and slash command. Not 4: it covers the common variations users would actually say across all three modes, matching the 'PDF files, PDFs, forms, .pdf' comprehensiveness anchor.

5 / 5

Distinctiveness Conflict Risk

Quotes: "Scaffolds, diagnoses, and prunes agent skills" — a clear meta-niche (skill lifecycle management) with mode-specific triggers ("why did the skill miss this", "prune my skills") that few other skills would claim. Not 4: overlap risk is limited to hypothetical rival skill-authoring skills; nothing generic in the description would fire for an unrelated skill.

5 / 5

Total

20

/

20

Passed

Validation

75%

Checks the skill against the spec for correct structure and formatting. All validation checks must pass before discovery and implementation can be scored.

Validation — 12 / 16 Passed

Validation for skill structure

CriteriaDescriptionResult

metadata_field

'metadata' should map string keys to string values

Warning

frontmatter_unknown_keys

Unknown frontmatter key(s) found; consider removing or moving to metadata

Warning

relative_links

Relative link issues: 16 missing

Warning

referenced_paths_exist

Referenced path issues: 3 missing

Warning

Total

12

/

16

Passed

Repository

mthines/agent-skills

Path

skills/authoring/create-skill/SKILL.md

Reviewed

Table of Contents

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