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posix-shell-pro

Expert in strict POSIX sh scripting for maximum portability across Unix-like systems. Specializes in shell scripts that run on any POSIX-compliant shell (dash, ash, sh, bash --posix).

38

Quality

36%

Does it follow best practices?

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tessl review fix ./skills/posix-shell-pro/SKILL.md
SKILL.md
Quality
Evals
Security

Quality

Content

32%Scale 1-5

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

This skill is a comprehensive but bloated reference document for POSIX shell scripting. Its main weakness is extreme verbosity with heavy repetition across sections (constraints, pitfalls, and best practices all cover the same bash-isms to avoid). It lacks a clear workflow, has no complete executable examples, and inlines far too much content that should be in separate reference files. The content reads more like a wiki article than an actionable skill for Claude.

Suggestions

Consolidate the overlapping sections (POSIX Constraints, Common Pitfalls, POSIX-Specific Best Practices) into a single concise reference table, and move detailed tool/reference lists to a separate bundle file.

Add a clear multi-step workflow: write script → run `shellcheck -s sh` → test with dash/ash → fix issues → re-validate, with explicit validation checkpoints.

Include at least one complete, executable example script (e.g., a portable argument-parsing template) rather than scattered one-liner snippets.

Move the tool lists, CI/CD integration details, embedded systems guidance, and references into separate bundle files (e.g., `resources/tools.md`, `resources/ci-cd.md`) and reference them from the main skill.

DimensionReasoningScore

Conciseness

Extremely verbose at ~300+ lines with massive repetition across sections. Many sections overlap (e.g., 'POSIX Constraints', 'Common Pitfalls to Avoid', 'POSIX-Specific Best Practices' all cover the same ground). Lists of tools, references, and focus areas are padded well beyond what Claude needs. Claude already knows most of these POSIX shell concepts.

2 / 5

Actionability

Provides concrete inline code snippets and patterns (e.g., trap usage, positional parameters for arrays, portable conditionals), but most guidance is bullet-point lists rather than executable, copy-paste-ready scripts. No complete script example demonstrating the full workflow. Many items are high-level directives ('Sanitize user input before using in commands') without showing how.

3 / 5

Workflow Clarity

No clear multi-step workflow is defined. The skill is a collection of categorized bullet points with no sequencing, no validation checkpoints, and no feedback loops. The 'Instructions' section is only 4 vague lines. The migration section hints at a workflow but lacks explicit steps with validation. For a skill that involves writing and validating scripts, there should be a clear write → lint → test → fix cycle.

2 / 5

Progressive Disclosure

References `resources/implementation-playbook.md` but no bundle files are provided, making this a dead reference. The massive amount of content (tool lists, references, advanced techniques, migration guides, CI/CD integration) is all inlined in a single file when much of it should be split into separate reference documents. The structure has many section headers but the content is monolithic.

2 / 5

Total

9

/

20

Passed

Description

39%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 establishes a clear niche in POSIX-compliant shell scripting with good distinctiveness, but it reads more like a bio ('Expert in...', 'Specializes in...') than an actionable skill description. It lacks concrete actions the skill performs and has no 'Use when...' clause to guide skill selection.

Suggestions

Add a 'Use when...' clause with trigger phrases like 'Use when the user asks for portable shell scripts, POSIX-compliant scripting, or scripts that must avoid bash-specific features.'

Replace the expertise claim with concrete actions, e.g., 'Writes portable POSIX sh scripts, converts bash scripts to POSIX-compliant equivalents, identifies bashisms, and ensures compatibility across dash, ash, and other POSIX shells.'

Include natural user terms and synonyms such as '.sh files', 'portable script', 'avoid bashisms', 'cross-platform shell script' to improve trigger term coverage.

DimensionReasoningScore

Specificity

Names the domain (POSIX sh scripting) and mentions portability, but the concrete actions are minimal — 'specializes in shell scripts that run on any POSIX-compliant shell' is more of a quality claim than a list of specific actions the skill performs.

2 / 5

Completeness

The 'what' is vaguely stated (writes POSIX sh scripts for portability) but lacks concrete actions. There is no 'when' clause — no 'Use when...' or equivalent trigger guidance, which per the rubric should cap completeness at 3, and the weak 'what' brings it to 2.

2 / 5

Trigger Term Quality

Includes relevant keywords like 'POSIX', 'sh', 'dash', 'ash', 'bash --posix', 'shell scripts', and 'portability', but misses natural user phrases like 'write a shell script', 'portable script', '.sh files', or 'POSIX-compatible'. The shell names are helpful but somewhat niche.

3 / 5

Distinctiveness Conflict Risk

The focus on strict POSIX sh scripting and portability across specific shells (dash, ash) is fairly distinctive and unlikely to conflict with general bash scripting or programming skills. Minor overlap risk with broader shell scripting skills.

4 / 5

Total

11

/

20

Passed

Validation

90%

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

Validation10 / 11 Passed

Validation for skill structure

CriteriaDescriptionResult

frontmatter_unknown_keys

Unknown frontmatter key(s) found; consider removing or moving to metadata

Warning

Total

10

/

11

Passed

Repository
administrakt0r/AI-Agents-Safe-Coding-Skills
Reviewed

Table of Contents

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