nix-profile-manager

Expert guidance for agents to manage local Nix profiles for installing tools and dependencies. Covers flakes, profile management, package searching, and registry configuration.

1.42x

Quality

52%

Does it follow best practices?

Impact

74%

1.42x

Average score across 3 eval scenarios

Securityby

Advisory

Suggest reviewing before use

Optimize this skill with Tessl

npx tessl skill review --optimize ./nix-profile-manager/SKILL.md

Quality

Discovery

32%

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 identifies the Nix ecosystem domain and lists relevant subtopics but lacks concrete actions and explicit trigger guidance. It reads more like a table of contents than a discriminating skill description. The absence of a 'Use when...' clause and specific actionable verbs significantly weakens its utility for skill selection.

Suggestions

Add an explicit 'Use when...' clause, e.g., 'Use when the user asks about installing packages with Nix, managing Nix profiles, configuring flakes, or searching nixpkgs.'

Replace topic-area nouns with concrete actions, e.g., 'Installs packages via nix profile install, searches nixpkgs, configures flake registries, and manages profile generations.'

Include common user-facing trigger terms like 'nix install', 'nixpkgs', 'nix shell', 'nix develop', and 'nix-env' to improve matching against natural user requests.

Dimension	Reasoning	Score
Specificity	Names the domain (Nix profiles) and lists some areas (flakes, profile management, package searching, registry configuration), but these are more like topic areas than concrete actions. It doesn't specify actions like 'install packages', 'remove packages', 'switch generations', etc.	2 / 3
Completeness	Describes what it covers at a high level but completely lacks a 'Use when...' clause or any explicit trigger guidance for when Claude should select this skill. Per the rubric, a missing 'Use when...' clause caps completeness at 2, and the 'what' is also weak, so this scores a 1.	1 / 3
Trigger Term Quality	Includes relevant terms like 'Nix', 'flakes', 'profile management', 'package searching', and 'registry configuration', but misses common user phrases like 'nix install', 'nix-env', 'nixpkgs', 'nix develop', 'nix shell', or 'install a tool with nix'.	2 / 3
Distinctiveness Conflict Risk	The mention of 'Nix profiles' and 'flakes' provides some distinctiveness from general package management skills, but 'installing tools and dependencies' is broad enough to overlap with skills for apt, brew, pip, or other package managers.	2 / 3
	Total	7 / 12 Passed

Implementation

72%

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

This is a solid skill with excellent actionability and good progressive disclosure. Its main weaknesses are moderate verbosity in the Core Concepts section (explaining things Claude already knows about Nix fundamentals) and a workflow that lacks explicit validation/verification steps after package installation. The troubleshooting section and agent implementation notes are practical additions.

Suggestions

Trim the 'Core Concepts' section significantly—Claude knows what flakes and profiles are. Keep only non-obvious details like nested package paths and the install/add version difference.

Add a verification step to the General Workflow after installation, e.g., `which git` or `nix profile list --profile "$AGENT_PROFILE"` to confirm success before proceeding.

Dimension	Reasoning	Score
Conciseness	The skill includes some unnecessary explanations (e.g., explaining what a profile directory contains, what a flake is, the difference between packages and flakes) that Claude likely already knows. The 'Core Concepts' section could be significantly trimmed. However, it's not egregiously verbose and most content is relevant.	2 / 3
Actionability	Commands are concrete, executable, and copy-paste ready throughout. The essential commands section provides specific bash commands with proper syntax, and the workflow section gives a clear end-to-end example. The NOTE about older Nix versions ('install' vs 'add') is a practical, actionable detail.	3 / 3
Workflow Clarity	The General Workflow section provides a clear sequence but lacks validation checkpoints. There's no verification step after installation (e.g., confirming the tool is accessible via `which tool-cmd`), and no error recovery loop. The troubleshooting section partially compensates but isn't integrated into the workflow itself.	2 / 3
Progressive Disclosure	The skill has a clear quick start, well-organized sections, and a References section pointing to one-level-deep external files (flakes.md, package-search.md, profile-internals.md, registry.md). Content is appropriately split between the overview and referenced materials.	3 / 3
	Total	10 / 12 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 — 11 / 11 Passed

Validation for skill structure

No warnings or errors.

Repository: YPares/agent-skills
Commit: aed1afb

Reviewed: 2 days ago

Table of Contents

Discovery Implementation Validation

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