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skill-creator

Guide for creating effective skills. This skill should be used when users want to create a new skill (or update an existing skill) that extends Gemini CLI's capabilities with specialized knowledge, workflows, or tool integrations.

56

Quality

66%

Does it follow best practices?

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SecuritybySnyk

Passed

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tessl review fix ./packages/core/src/skills/builtin/skill-creator/SKILL.md
SKILL.md
Quality
Evals
Security

Quality

Content

63%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-structured meta-skill with a clear seven-step workflow, explicit validation feedback loops, and concrete commands for the main operations. Its main deficits are broken references (workflows.md, output-patterns.md, and the 'available_resources' section do not exist in the bundle), placeholder paths, and some padded explanation that could be tightened.

Suggestions

Ship references/workflows.md and references/output-patterns.md (or remove the pointers) — Step 4 directs the agent to consult files that are not in the bundle.

Resolve the '<path-to-skill-creator>' placeholders and the missing 'available_resources' section, or replace them with the actual relative script paths in this skill's scripts/ directory.

Trim redundant content: the bridge/cliffs analogy, the duplicated references-guidance paragraphs, and the stray 'REDLINING.md or OOXML.md' sentence under the CSV example (which references PANDAS.md/STREAMING.md/TIMESTAMPS.md).

DimensionReasoningScore

Conciseness

The body is mostly efficient imperative guidance, but includes unnecessary padding: the bridge/cliffs analogy, 'The context window is a public good' framing, re-explaining the same references guidance twice in the References section, and leftover boilerplate like 'Gemini CLI reads REDLINING.md or OOXML.md' under a CSV example that names different files. This matches anchor 3 ('mostly efficient but includes some unnecessary explanation or could be tightened') rather than 4, since multiple sections could be trimmed.

3 / 5

Actionability

Concrete executable commands are given for init, packaging, and both install scopes, plus explicit naming rules and a worked example of description writing. It falls short of anchor 5 because key paths are placeholders ('<path-to-skill-creator>', an 'available_resources' section that does not exist in this SKILL.md) and Step 4 directs the reader to consult references/workflows.md and references/output-patterns.md, which are not in the bundle.

4 / 5

Workflow Clarity

The 7-step creation process is clearly sequenced with per-step skip conditions, an automatic validation pass in packaging, an explicit error-recovery loop ('If validation fails... fix any validation errors and run the packaging command again'), and a testing requirement for added scripts. It misses anchor 5 because Step 4's 'Learn Proven Design Patterns' points to nonexistent reference files, leaving a gap an agent cannot actually execute.

4 / 5

Progressive Disclosure

The body teaches and models progressive-disclosure patterns well, but measured against the actual bundle: references/workflows.md and references/output-patterns.md are cited yet no references/ directory exists, the 'available_resources' section it points to is absent, and validate_skill.cjs exists in scripts/ but is never mentioned. Per the guideline to score against the actual bundle structure, broken/unverified reference paths place this at anchor 3 (references present but not reliably signaled/organized) rather than 4.

3 / 5

Total

14

/

20

Passed

Description

70%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 solid description with an explicit 'when' trigger clause naming both create and update paths, written in third person. Its main weaknesses are a thin 'what' (it never says what the guide covers — naming, structure, packaging, installation) and limited trigger-term variation.

Suggestions

Enumerate the concrete actions the skill performs, e.g. 'Creates, validates, and packages skill bundles: naming, frontmatter description writing, scripts/references/assets structure, and .skill installation.'

Add natural trigger variations users might say, such as 'build a skill', 'make a new skill', 'add a skill to Gemini CLI', or 'fix a skill that triggers badly'.

Make the 'what' concrete instead of 'effective skills' — state that it generates the skill scaffold, writes the SKILL.md, and packages/installs it.

DimensionReasoningScore

Specificity

The description names the domain ("creating effective skills") and one or two actions ("create a new skill (or update an existing skill)"), but does not enumerate the concrete capabilities involved (naming conventions, init/packaging scripts, installation scopes). This matches the anchor 'Names domain and 1-2 concrete actions, but not comprehensive' — above 2 because the actions are concrete, below 4 because coverage is not several specific actions.

3 / 5

Completeness

Both parts are present and explicit: what ("Guide for creating effective skills") and when ("This skill should be used when users want to create a new skill (or update an existing skill) that extends Gemini CLI's capabilities..."). The 'when' clause is strong, but the 'what' is thin and generic ("effective skills" does not state what the guide actually covers), so it falls short of the anchor-5 example where both are concrete and comprehensive.

4 / 5

Trigger Term Quality

It captures the natural phrasings a user would say — "when users want to create a new skill (or update an existing skill)" — plus "specialized knowledge, workflows, or tool integrations". This sits between anchor 3 (missing common variations) and anchor 5 (comprehensive synonyms/extensions): core triggers are natural and complete, but variations like "build/make/write a skill" or "skill package" are absent.

4 / 5

Distinctiveness Conflict Risk

Skill creation is a clear niche with distinct triggers ("create a new skill", "update an existing skill") that would not fire for ordinary domain tasks. It stays below 5 only because phrases like "Guide for..." and "specialized knowledge, workflows, or tool integrations" are broad enough to mildly overlap with general authoring/documentation skills.

4 / 5

Total

15

/

20

Passed

Validation

81%

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

Validation — 13 / 16 Passed

Validation for skill structure

CriteriaDescriptionResult

skill_md_line_count

SKILL.md is long (520 lines); consider splitting into references/ and linking

Warning

relative_links

Relative link issues: 6 missing

Warning

referenced_paths_exist

Referenced path issues: 17 missing

Warning

Total

13

/

16

Passed

Repository
google-gemini/gemini-cli
Reviewed

Table of Contents

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