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nushell-usage

Essential patterns, idioms, and gotchas for writing Nushell code. Use when writing Nushell scripts, functions, or working with Nushell's type system, pipelines, and data structures. Complements plugin development knowledge with practical usage patterns.

83

1.02x
Quality

79%

Does it follow best practices?

Impact

85%

1.02x

Average score across 3 eval scenarios

SecuritybySnyk

Advisory

Suggest reviewing before use

Fix and improve this skill with Tessl

tessl review fix ./nushell-usage/SKILL.md
SKILL.md
Quality
Evals
Security

Quality

Content

77%

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

This is a strong, highly actionable Nushell patterns reference with excellent use of concrete code examples and clear ❌/✅ comparisons. The critical distinction between pipeline input and parameters is well-highlighted. Minor weaknesses include some verbosity in best practices (items Claude already knows), dead references to bundle files that weren't provided, and a document length that could benefit from more aggressive splitting into referenced files.

Suggestions

Trim the best practices list to only Nushell-specific guidance — remove generic advice like 'document with comments' and 'test incrementally' that Claude already knows.

Provide the referenced bundle files (references/advanced-patterns.md and references/type-system.md) or remove the references to avoid dead links.

DimensionReasoningScore

Conciseness

Generally efficient with good use of code examples, but includes some unnecessary explanations (e.g., 'Why this matters' section explaining lazy vs eager evaluation, the best practices list has items Claude already knows like 'document with comments' and 'test incrementally'). The external resources section at the end adds little value. Overall mostly lean but could be tightened.

2 / 3

Actionability

Excellent actionability throughout — nearly every pattern includes executable, copy-paste-ready Nushell code with correct syntax. The ❌/✅ pattern clearly shows wrong vs right approaches. Code examples are concrete and complete, covering real use cases like records, tables, closures, error handling, and iteration.

3 / 3

Workflow Clarity

For a reference/patterns skill (not a multi-step workflow skill), the content is exceptionally well-sequenced. It progresses logically from critical distinctions through common patterns to pitfalls and advanced topics. Each section is self-contained and clearly labeled. Since this is a patterns reference rather than a destructive/batch operation workflow, explicit validation checkpoints aren't required.

3 / 3

Progressive Disclosure

The skill references two bundle files (references/advanced-patterns.md and references/type-system.md) which is good structure, but no bundle files were provided, making these dead references. The main file itself is quite long (~300+ lines) and some sections like the detailed iteration patterns or row conditions vs closures could potentially be split out. The external resources section at the end is a nice touch but the internal references can't be verified.

2 / 3

Total

10

/

12

Passed

Description

82%

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 effectively communicates when to use the skill with explicit trigger guidance and good Nushell-specific keywords. Its main weakness is the lack of concrete action verbs—'patterns, idioms, and gotchas' is abstract rather than describing specific capabilities like parsing, error handling, or command definition. The relationship to the companion plugin development skill could also be more precisely delineated.

Suggestions

Replace abstract terms like 'patterns, idioms, and gotchas' with concrete actions such as 'define custom commands, handle types and errors, manipulate tables and records, construct pipelines'.

Clarify the boundary with the plugin development skill more explicitly, e.g., 'Use for general Nushell scripting; for building Nushell plugins, use [other skill]'.

DimensionReasoningScore

Specificity

The description names the domain (Nushell) and mentions some areas like 'type system, pipelines, and data structures,' but uses abstract terms like 'patterns, idioms, and gotchas' rather than listing concrete actions (e.g., 'parse tables, define custom commands, handle errors').

2 / 3

Completeness

Clearly answers both 'what' (patterns, idioms, and gotchas for writing Nushell code) and 'when' (explicit 'Use when writing Nushell scripts, functions, or working with Nushell's type system, pipelines, and data structures').

3 / 3

Trigger Term Quality

Includes strong natural trigger terms: 'Nushell scripts', 'Nushell functions', 'Nushell's type system', 'pipelines', 'data structures', and 'Nushell code'. These are terms users would naturally use when seeking help with Nushell programming.

3 / 3

Distinctiveness Conflict Risk

The mention of 'Complements plugin development knowledge' suggests there's a related skill, and the description does differentiate itself somewhat. However, terms like 'pipelines' and 'data structures' are generic enough to potentially overlap with other shell or scripting skills. The Nushell specificity helps but the boundary with the plugin development skill could be clearer.

2 / 3

Total

10

/

12

Passed

Validation

90%

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

Validation10 / 11 Passed

Validation for skill structure

CriteriaDescriptionResult

frontmatter_unknown_keys

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

Warning

Total

10

/

11

Passed

Repository
YPares/agent-skills
Reviewed

Table of Contents

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