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builtin-skills

Use when creating a new builtin skill for Crush, editing an existing builtin skill (internal/skills/builtin/), or when the user needs to understand how the embedded skill system works.

71

Quality

86%

Does it follow best practices?

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SecuritybySnyk

Passed

No findings from the security scan

SKILL.md
Quality
Evals
Security

Quality

Content

86%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 concise, well-structured, and actionable with concrete paths and commands, plus a clear numbered workflow ending in a build/test verification step. As a simple instruction-only skill under 50 lines it appropriately needs no external references.

Suggestions

Add a brief feedback loop to the 'Adding a New Builtin Skill' workflow, e.g. 'If the build fails, verify the directory name matches the name field and that SKILL.md frontmatter is valid.'

Show a minimal concrete example of the test assertion expected in TestDiscoverBuiltin rather than only describing it in prose.

DimensionReasoningScore

Conciseness

The body is lean (~33 lines), assumes Claude's knowledge of Go embed directives and testing, and avoids explaining what skills or PDFs are; every line earns its place. Not below 5 because there is no detectable padding or redundant explanation.

5 / 5

Actionability

Provides concrete file paths (internal/skills/builtin/<skill-name>/SKILL.md), exact build/test commands (go build . && go test ./internal/skills/...), and a precise embed directive (//go:embed builtin/*). Score capped below 5 because it is instruction-only with no executable code block, and the "add a test assertion" step is described but not shown concretely.

4 / 5

Workflow Clarity

The "Adding a New Builtin Skill" section is a clear 4-step numbered sequence culminating in a build-and-test verification command (step 4). Not a 5 because there is no explicit feedback loop describing what to do if the build/test fails, though the operation is non-destructive so the missing feedback loop is a minor gap rather than a hard cap.

4 / 5

Progressive Disclosure

Content is under 50 lines, single-purpose, with well-organized section headers (How It Works, Adding a New Builtin Skill, Existing Builtin Skills) and no need for external references; per the simple-skills note this qualifies for a 5. No bundle files exist, so no nested-reference risk.

5 / 5

Total

18

/

20

Passed

Description

87%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.

The description is clear, well-scoped, and uses an explicit "Use when" trigger with multiple concrete scenarios tied to the Crush builtin skill system. It distinguishes itself well from generic skills and answers both what and when.

DimensionReasoningScore

Specificity

Names the domain (Crush builtin skills) and several concrete actions — "creating a new builtin skill", "editing an existing builtin skill", "understand how the embedded skill system works" — with only minor coverage gaps. Not a 5 because it lacks additional specific sub-tasks like discovery testing or embedding details explicitly as capabilities.

4 / 5

Completeness

Clearly answers "what" (creating/editing/understanding builtin skills) and explicitly answers "when" via the "Use when ... or when the user needs to understand" trigger clause with concrete scenarios. Not below 5 because both what and when are explicit and concrete.

5 / 5

Trigger Term Quality

Includes natural trigger phrases such as "Use when creating", "editing an existing builtin skill", and "understand how the embedded skill system works" that a user might say, but misses common synonyms or variations. Not a 5 because coverage of alternative phrasings is thin; not a 3 because the present terms are genuinely natural rather than generic.

4 / 5

Distinctiveness Conflict Risk

The niche is tightly scoped to Crush's embedded skill system at internal/skills/builtin/, with triggers unlikely to fire for unrelated skills. Minimal conflict risk because the path and "builtin skill" framing are specific to this single domain.

5 / 5

Total

18

/

20

Passed

Validation

100%

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

Validation16 / 16 Passed

Validation for skill structure

No warnings or errors.

Repository
charmbracelet/crush
Reviewed

Table of Contents

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