nushell-plugin-builder

Guide for creating Nushell plugins in Rust using nu_plugin and nu_protocol crates. Use when users want to build custom Nushell commands, extend Nushell with new functionality, create data transformations, or integrate external tools/APIs into Nushell. Covers project setup, command implementation, streaming data, custom values, and testing.

1.20x

Quality

83%

Does it follow best practices?

Impact

95%

1.20x

Average score across 3 eval scenarios

Securityby

Low

Low-risk findings worth noting

Quality

Content

78%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 skill body is a code-dense, actionable guide with a clean quick-start flow and well-organized one-level-deep references that all exist on disk. Its main weakness is a few placeholder snippets and only implicit error-recovery feedback in the dev workflow.

Suggestions

Make the streaming PipelineData example executable by replacing the `/* condition */` placeholder and `...` with a concrete filter predicate and full signature.

Add an explicit validation/feedback checkpoint in the Development Workflow (e.g. 'If `cargo build` fails, fix the errors then rebuild before re-registering the plugin').

Convert the bare backtick reference paths (e.g. `references/advanced-features.md`) into markdown links so they are directly navigable.

Dimension	Reasoning	Score
Conciseness	Mostly lean code-first content with brief framing and no over-explanation of basic Rust/plugin concepts; a few minor sentences ('This shows users exactly where the error occurred in their command') could be trimmed.	4 / 5
Actionability	Provides extensive copy-paste-ready Rust and shell commands across project setup, signatures, argument access, error handling, serialization, common patterns, and testing, with only minor gaps (e.g. the streaming example uses `/* condition */` and `...` placeholders).	4 / 5
Workflow Clarity	Quick Start and Development Workflow give clearly sequenced, concrete steps with build/test commands and a reload loop; this is non-destructive plugin scaffolding so the destructive-cap does not apply, but explicit 'if build fails, fix and rebuild' feedback checkpoints are only implicit.	4 / 5
Progressive Disclosure	Clear overview body with well-signaled, one-level-deep references (advanced-features.md, examples.md, testing-debugging.md, plugin-protocol.md) plus a scaffold script and template asset, all verified to exist; navigation is easy via the Reference Documentation section.	5 / 5
	Total	17 / 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 third-person, clearly scoped to Nushell Rust plugin development, and answers both 'what' and 'when' with concrete triggers. It is strong across the board, with only slight room to tighten trigger-term variants.

Dimension	Reasoning	Score
Specificity	Lists several concrete actions ('build custom Nushell commands', 'create data transformations', 'integrate external tools/APIs') plus a coverage list ('project setup, command implementation, streaming data, custom values, and testing'), with only minor generic phrasing like 'extend Nushell with new functionality'.	4 / 5
Completeness	Explicitly answers both what ('Guide for creating Nushell plugins in Rust... Covers project setup, command implementation, streaming data, custom values, and testing') and when ('Use when users want to build custom Nushell commands...') with concrete trigger phrases.	5 / 5
Trigger Term Quality	Good natural keyword coverage ('Nushell plugins', 'custom Nushell commands', 'data transformations', 'integrate external tools/APIs') that users would plausibly say, though a few common variants (e.g. file extensions or 'Rust plugin') are absent.	4 / 5
Distinctiveness Conflict Risk	Names a very specific niche ('creating Nushell plugins in Rust using nu_plugin and nu_protocol crates') with distinct triggers and minimal overlap risk with other skills.	5 / 5
	Total	18 / 20 Passed

Validation

100%

Warnings & errors only

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

Validation — 16 / 16 Passed

Validation for skill structure

No warnings or errors.

Repository: YPares/agent-skills
Path: nushell-plugin-builder/SKILL.md
Commit: e9d2149

Reviewed: 3 days ago

Table of Contents

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