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nix-best-practices

Nix patterns for flakes, overlays, unfree handling, and binary overlays. Use when working with flake.nix or shell.nix.

82

1.59x
Quality

75%

Does it follow best practices?

Impact

91%

1.59x

Average score across 3 eval scenarios

SecuritybySnyk

Passed

No findings from the security scan

Fix and improve this skill with Tessl

tessl review fix ./data/skills-md/0xbigboss/claude-code/nix-best-practices/SKILL.md
SKILL.md
Quality
Evals
Security

Quality

Content

82%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.

A highly actionable, well-organized reference of executable Nix patterns with clear troubleshooting. It earns top actionability marks but would benefit from validation checkpoints in its risky workflows and from offloading the large binary-overlay template to a reference file.

Suggestions

Add explicit validation checkpoints to destructive/batch workflows — e.g., after fetching a binary, verify the SRI hash with 'nix hash to-sri' and re-validate before declaring the overlay complete.

Move the lengthy binary-overlay template and SHA256 tooling into a separate references file (e.g., BINARY-OVERLAY.md) and link to it from the body to improve progressive disclosure.

Trim the inline comments in code blocks that restate obvious behavior, and consolidate the three unfree-handling options with a clearer decision sequence (try Option 1, fall back to Option 2/3) with verification steps.

DimensionReasoningScore

Conciseness

Mostly efficient: code blocks are annotated with brief inline comments and minimal prose, assuming Claude's knowledge of Nix; a few sections (e.g., the large binary-overlay template) could be trimmed or moved to a reference.

4 / 5

Actionability

Copy-paste-ready executable Nix snippets and concrete commands (e.g., 'nix-prefetch-url', 'nix hash to-sri') covering the common cases across flakes, overlays, unfree, dev shells, and direnv.

5 / 5

Workflow Clarity

Procedures are clearly sequenced with troubleshooting sections, but the destructive/batch operations (binary overlay creation, hash re-fetching) lack explicit validate-then-proceed checkpoints and feedback loops.

4 / 5

Progressive Disclosure

Well-organized into topical sections with no bundle files and no nested references; the only gap is that the long binary-overlay template and hash tooling could be split into a separate reference file.

4 / 5

Total

17

/

20

Passed

Description

67%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.

A solid, concise description that states capabilities and a 'Use when' trigger, with clear file-name anchors. Trigger-term coverage and explicitness of the 'when' could be broadened slightly.

DimensionReasoningScore

Specificity

Names the domain (Nix) plus several concrete actions/patterns ('patterns for flakes, overlays, unfree handling, and binary overlays'), with minor gaps (e.g., dev shells not surfaced in the description).

4 / 5

Completeness

Clearly states both what ('Nix patterns for flakes, overlays, unfree handling, and binary overlays') and when ('Use when working with flake.nix or shell.nix'), though the 'when' could be more explicit about additional triggers.

4 / 5

Trigger Term Quality

Includes core natural terms ('flake.nix', 'shell.nix', 'overlays') but lacks common synonyms a user might say (e.g., 'NixOS', 'nix develop', 'nixpkgs') and has no file extensions beyond .nix.

3 / 5

Distinctiveness Conflict Risk

Targets a clear, specific niche (Nix flake/shell patterns) with file-name triggers, giving minimal overlap risk with general coding skills.

4 / 5

Total

15

/

20

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.

Validation16 / 16 Passed

Validation for skill structure

No warnings or errors.

Repository
NeverSight/skills_feed
Reviewed

Table of Contents

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