nix-best-practices
Nix patterns for flakes, overlays, unfree handling, and binary overlays. Use when working with flake.nix or shell.nix.
79
70%
Does it follow best practices?
Impact
91%
1.59xAverage score across 3 eval scenarios
Passed
No known issues
Optimize this skill with Tessl
npx tessl skill review --optimize ./data/skills-md/0xbigboss/claude-code/nix-best-practices/SKILL.mdQuality
Discovery
75%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 establishes a clear niche in the Nix ecosystem and includes an explicit 'Use when' clause with file-based triggers, which is strong. However, it describes capabilities as 'patterns' rather than listing concrete actions (like creating, configuring, debugging), and could benefit from broader trigger term coverage to capture more Nix-related user queries.
Suggestions
Replace 'Nix patterns for' with concrete actions like 'Creates and configures Nix flakes, sets up overlays, handles unfree packages, and manages binary overlays'
Expand trigger terms to include common variations like 'nixpkgs', 'devShell', 'nix develop', 'derivation', or 'NixOS configuration'
| Dimension | Reasoning | Score |
|---|---|---|
Specificity | Names the domain (Nix) and lists some specific concepts (flakes, overlays, unfree handling, binary overlays), but describes them as 'patterns' rather than concrete actions. It doesn't specify what actions are performed (e.g., 'create flakes', 'configure overlays', 'enable unfree packages'). | 2 / 3 |
Completeness | Clearly answers both 'what' (Nix patterns for flakes, overlays, unfree handling, binary overlays) and 'when' (Use when working with flake.nix or shell.nix) with an explicit 'Use when...' clause. | 3 / 3 |
Trigger Term Quality | Includes relevant keywords like 'flake.nix', 'shell.nix', 'flakes', 'overlays', and 'Nix', which users would naturally mention. However, it misses common variations like 'nixpkgs', 'nix-shell', 'devShell', 'nix develop', 'nixos', or 'derivation' that users might also say. | 2 / 3 |
Distinctiveness Conflict Risk | Nix is a very specific ecosystem, and the mention of flake.nix and shell.nix creates a clear, distinct niche that is unlikely to conflict with other skills. The trigger files are unique to Nix. | 3 / 3 |
Total | 10 / 12 Passed |
Implementation
64%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, actionable Nix reference skill with comprehensive, executable code examples covering flakes, overlays, unfree packages, and dev shells. Its main weaknesses are the monolithic structure that could benefit from progressive disclosure into separate files, and the lack of explicit validation/verification steps in multi-step workflows like creating binary overlays. The content is mostly concise but has room for tightening in a few areas.
Suggestions
Add explicit validation checkpoints to multi-step workflows, e.g., after creating a binary overlay: 'Verify: nix build .#tool && nix run .#tool -- --version'
Split the binary overlay pattern and dev shell patterns into separate referenced files to improve progressive disclosure and reduce the main file's length
| Dimension | Reasoning | Score |
|---|---|---|
Conciseness | The skill is mostly efficient with good code examples, but includes some unnecessary explanations (e.g., 'Overlays modify or add packages to nixpkgs') and could be tightened in places. The binary overlay section is quite lengthy with placeholder hashes that add bulk. However, most content is genuinely useful Nix-specific knowledge that Claude wouldn't inherently know. | 2 / 3 |
Actionability | Provides fully executable, copy-paste ready Nix code for every pattern — flake structure, overlays, unfree handling, binary overlays, dev shells, direnv integration, and CLI commands. The code examples are complete and concrete with specific syntax rather than pseudocode. | 3 / 3 |
Workflow Clarity | Individual patterns are clear, but multi-step processes lack explicit validation checkpoints. For example, the binary overlay creation doesn't include a 'build and test' verification step, and the overlay application workflow doesn't mention checking that overlays were applied correctly. The troubleshooting section partially compensates but is reactive rather than proactive. | 2 / 3 |
Progressive Disclosure | The content is well-organized with clear section headers, but it's a monolithic document (~200 lines) that could benefit from splitting detailed patterns (binary overlay repos, dev shell patterns) into separate referenced files. No bundle files are provided, and no references to external files exist for advanced topics. | 2 / 3 |
Total | 9 / 12 Passed |
Validation
100%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
- NeverSight/skills_feed
- Commit
aa009ea
- Reviewed
Table of Contents
Is this your skill?
If you maintain this skill, you can claim it as your own. Once claimed, you can manage eval scenarios, bundle related skills, attach documentation or rules, and ensure cross-agent compatibility.