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

48%

Does it follow best practices?

Impact

74%

1.42x

Average score across 3 eval scenarios

Securityby

Advisory

Suggest reviewing before use

Fix and improve this skill with Tessl

tessl review fix ./nix-profile-manager/SKILL.md

Quality

Content

64%

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

The skill provides solid, actionable Nix profile management guidance with executable commands and good troubleshooting coverage. Its main weaknesses are verbosity in the conceptual sections (explaining things Claude already knows about Nix fundamentals) and a lack of explicit validation steps in the workflow. The reference file structure is well-designed but cannot be verified without bundle files.

Suggestions

Trim or remove the 'Core Concepts' section — Claude already understands flakes, profiles, and the package/flake distinction. Keep only non-obvious details like the nested package syntax note.

Add a validation step after `nix profile add` in the General Workflow, e.g., `nix profile list --profile "$AGENT_PROFILE" | grep git` or running the installed tool to confirm success.

Include the referenced bundle files (references/flakes.md, etc.) or remove the references section if they don't exist.

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 would already know. The 'Core Concepts' section could be significantly trimmed. However, the command examples themselves are lean and useful.	2 / 3
Actionability	The skill provides fully executable, copy-paste ready commands for all operations: searching, installing, listing, removing, upgrading, and registry management. The commands use concrete examples with proper syntax and flags.	3 / 3
Workflow Clarity	The 'General Workflow' section provides a clear sequence but lacks validation checkpoints — there's no step to verify the package was installed successfully (e.g., checking `nix profile list` output or running the tool). The note about checking `$AGENT_PROFILE` is good, but there's no error recovery loop after installation.	2 / 3
Progressive Disclosure	The skill references four files under 'References' (flakes.md, package-search.md, profile-internals.md, registry.md) which is good structure, but no bundle files were provided, so these references are unverifiable. The inline content includes conceptual material (Core Concepts) that could have been offloaded to reference files, making the main skill leaner.	2 / 3
	Total	9 / 12 Passed

Description

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 topic areas 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 significantly weakens its utility for skill selection among many options.

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 listings with concrete actions, e.g., 'Installs, removes, and lists packages in local Nix profiles. Configures flake inputs and Nix registries. Searches nixpkgs for available packages.'

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

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 what actions are performed (e.g., 'install packages', 'remove packages', 'list installed packages').	2 / 3
Completeness	It describes what the skill 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 only weakly specified, so this scores a 1.	1 / 3
Trigger Term Quality	Includes relevant terms like 'Nix', 'flakes', 'profile management', 'package searching', and 'registry configuration', which are natural for Nix users. However, it misses common variations like 'nix-env', 'nix profile install', 'nixpkgs', 'nix shell', or simpler terms like 'install package with nix'.	2 / 3
Distinctiveness Conflict Risk	The mention of 'Nix profiles' and 'flakes' provides some distinctiveness since Nix is a specific ecosystem. However, 'installing tools and dependencies' is generic enough to potentially overlap with other package management skills (e.g., apt, brew, pip).	2 / 3
	Total	7 / 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: bc4c2ce

Reviewed: 9 days ago

Table of Contents

Discovery Implementation Validation

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