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authoring-skills

How to create and maintain agent skills in .agents/skills/. Use when creating a new SKILL.md, writing skill descriptions, choosing frontmatter fields, or deciding what content belongs in a skill vs AGENTS.md. Covers the supported spec fields, description writing, naming conventions, and the relationship between always-loaded AGENTS.md and on-demand skills.

Quality

89%

Does it follow best practices?

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SKILL.md
Quality
Evals
Security

Quality

Content

83%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.

A well-crafted, token-efficient reference: concrete templates, examples, and naming conventions with essentially no padding, and excellent copy-paste-ready frontmatter guidance. Its weakest area is workflow clarity — the authoring process is conveyed through well-ordered sections rather than an explicit step sequence with validation checkpoints — and progressive disclosure relies entirely on inline sections with no reference files. Both are reasonable choices at this scale but leave room for a more procedural, checkpoint-driven layout.

Suggestions

Add a numbered "Creating a skill" procedure that sequences the existing sections into explicit steps (1. decide skill vs AGENTS.md, 2. create the directory and frontmatter from the template, 3. write the description using the checklist, 4. add the `$skill-name` pointer to AGENTS.md), so the implicit section order becomes an explicit workflow.

Include a validation checkpoint at the end of the creation workflow, e.g. re-read the description and confirm it names the trigger scenario and key file names, or verify the frontmatter contains only supported fields — closing the checkpoint gap that currently caps workflow clarity.

If the skill grows beyond its current size (e.g. adding a full worked SKILL.md example), move the description-writing guide and content conventions into a reference file (e.g. writing-descriptions.md) referenced one level deep from SKILL.md, exercising the hub + detail pattern the skill itself teaches.

DimensionReasoningScore

Conciseness

The body is a lean reference of repo-specific conventions — the supported-frontmatter field table, good/bad description examples, naming rules, and the AGENTS.md-vs-skill comparison table — with no explanation of concepts Claude already knows. Every section carries non-obvious prescriptive information ("Only use fields from this list. Unknown fields are silently ignored.", "No repo prefix (already scoped by `.agents/skills/`)"), matching the anchor for every token earning its place. At most the two file-tree diagrams trivially overlap, which is not enough to drop to anchor 4's "minor instances of over-explanation".

5 / 5

Actionability

For an instruction-only skill, the guidance is fully actionable and copy-paste ready: a complete frontmatter template with per-field semantics ("argument-hint: '<pr-number>' # Optional. Hint for expected arguments."), concrete good/bad description examples ("description: Helps with flags." vs the good multi-line form), explicit naming rules ("Hyphens for multi-word names"), and the hub + detail file pattern. These cover the common case — creating a new skill — end to end. The one gap is that no full worked example of a finished SKILL.md body is shown, but the pieces provided are executable as-is, so this sits at anchor 5 rather than 4.

5 / 5

Workflow Clarity

Sections are logically ordered (when to create → file structure → frontmatter → description writing → content conventions → naming), but the sequence is only implicit: there is no explicit step-by-step authoring procedure and no validation checkpoints (e.g. a step to verify the new skill triggers or that the frontmatter parses). This matches anchor 3 ("sequence present but checkpoints missing or implicit") rather than anchor 4, which requires most checkpoints to be present. It is above anchor 2 because the organization is coherent with few gaps, and the skill involves no destructive or batch operations, so the workflow-clarity cap does not apply.

3 / 5

Progressive Disclosure

The body has good structure with clear, well-scoped sections and appropriately sized inline content (~104 lines), and it models the hub + detail pattern for other skills (workflow.md, local-repro.md). No bundle files exist (references/, scripts/, assets/ are absent), so everything is inline — appropriate at this size but without any actual one-level-deep reference split, which is what anchor 5 rewards. This places it at anchor 4 (good structure, minor organization gaps) rather than 5; not 3, since no content that clearly belongs in a separate file is inlined and navigation is easy.

4 / 5

Total

17

/

20

Passed

Description

92%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 strong description: it states concrete capabilities, includes an explicit multi-scenario "Use when..." clause, and names the specific artifacts (SKILL.md, frontmatter, AGENTS.md) that serve as reliable triggers. The only weakness is keyword breadth — a few natural phrasings a user might use are absent. Voice is appropriate (no first/second person), and there is no fluff or over-claiming.

DimensionReasoningScore

Specificity

The description lists multiple concrete actions across the whole skill-authoring domain: "create and maintain agent skills", "writing skill descriptions", "choosing frontmatter fields", and "deciding what content belongs in a skill vs AGENTS.md", plus topic coverage of "supported spec fields, description writing, naming conventions". Coverage is comprehensive with no meaningful gaps, matching the anchor for multiple specific concrete actions rather than the anchor-4 case of minor gaps.

5 / 5

Completeness

It explicitly answers both questions: the "what" ("How to create and maintain agent skills... Covers the supported spec fields, description writing, naming conventions, and the relationship between always-loaded AGENTS.md and on-demand skills") and the "when" with four concrete trigger scenarios ("Use when creating a new SKILL.md, writing skill descriptions, choosing frontmatter fields, or deciding what content belongs in a skill vs AGENTS.md"). This clearly matches the anchor-5 example pairing a concrete capability statement with explicit 'Use when...' triggers.

5 / 5

Trigger Term Quality

Natural trigger terms are present and specific — "SKILL.md", "skill descriptions", "frontmatter fields", "AGENTS.md", "agent skills" — which a user requesting this work would plausibly say. A few natural variants are missing (e.g. "add a new skill", "skill metadata", "slash command"), so it falls short of the anchor-5 standard of comprehensive synonym- and extension-level coverage but exceeds anchor 3, which requires missing common variations.

4 / 5

Distinctiveness Conflict Risk

It occupies a clear niche — authoring skills in `.agents/skills/` — with triggers anchored to distinct artifacts (SKILL.md, frontmatter fields, AGENTS.md), making accidental activation for unrelated skills unlikely. It is far more distinct than the anchor-4 example ("Works with PDF and Word document files"), which still carries cross-format overlap risk.

5 / 5

Total

19

/

20

Passed

Validation

87%

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

Validation — 14 / 16 Passed

Validation for skill structure

CriteriaDescriptionResult

metadata_version

'metadata.version' is missing

Warning

metadata_field

'metadata' should map string keys to string values

Warning

Total

14

/

16

Passed

Repository

vercel/next.js

Path

.agents/skills/authoring-skills/SKILL.md

Reviewed

Table of Contents

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