sandi-metz-rules

This skill should be used when users request code review, refactoring, or code quality improvements for Ruby codebases. Apply Sandi Metz's four rules for writing maintainable object-oriented code - classes under 100 lines, methods under 5 lines, no more than 4 parameters, and controllers instantiate only one object. Use when users mention "Sandi Metz", "code quality", "refactoring", or when reviewing Ruby code for maintainability.

Install with Tessl CLI

npx tessl i github:Dicklesworthstone/pi_agent_rust --skill sandi-metz-rules

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Review — 86%

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Learn more

Validation — 11 / 11 Passed

Validation for skill structure

SKILL.md

Review

Evals

Evaluation results

100%

14%

Ruby Code Quality Audit

Precise code measurement rules

Criteria

Without context

With context

Method line counting

100%

Blank lines excluded from methods

100%

Block param excluded

100%

Keyword args counted as params

100%

Default params counted

50%

100%

Class line counting

100%

Violation prioritization

100%

Routes DSL acceptable

100%

Specific line numbers

100%

Method extraction suggestion

100%

Parameter object suggestion

100%

Without context: $0.8927 · 4m 28s · 20 turns · 27 in / 19,061 out tokens

With context: $0.8053 · 3m 1s · 24 turns · 2,651 in / 13,314 out tokens

100%

11%

Ruby Codebase Health Review

Full codebase review with refactoring examples

Criteria

Without context

With context

File locations and line numbers

100%

Largest violations identified first

100%

Parameter violation flagged

100%

Method length violation flagged

25%

100%

Prioritized severity list

100%

Named pattern for long method

70%

100%

Named pattern for too many params

100%

Before/after for parameter violation

100%

Before/after for method length

80%

100%

Refactoring benefit explained

100%

Summary statistics

100%

Without context: $0.3402 · 1m 51s · 13 turns · 18 in / 6,639 out tokens

With context: $0.8515 · 3m 22s · 23 turns · 2,651 in / 14,149 out tokens

100%

20%

Rails Controller Cleanup and Enforcement Setup

Fat controller refactoring and automation

Criteria

Without context

With context

Single object instantiation

100%

Finder calls not counted

100%

Named extraction pattern

100%

Before/after controller comparison

100%

RuboCop ClassLength limit

100%

RuboCop MethodLength limit

100%

RuboCop ParameterLists limit

100%

Additional tools mentioned

100%

Violation counts identified

100%

Service object handles full flow

100%

Without context: $0.3118 · 1m 32s · 16 turns · 23 in / 5,179 out tokens

With context: $0.6204 · 1m 59s · 27 turns · 2,907 in / 7,553 out tokens

Evaluated: about 13 hours ago
Agent: Claude Code

Table of Contents

Ruby Code Quality Audit Ruby Codebase Health Review Rails Controller Cleanup and Enforcement Setup

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