rails-concern
Creates Rails concerns for shared behavior across models or controllers with TDD. Use when extracting shared code, creating reusable modules, DRYing up models/controllers, or when user mentions concerns, modules, mixins, or shared behavior.
Install with Tessl CLI
npx tessl i github:fernandezbaptiste/rails_ai_agents --skill rails-concern90
Does it follow best practices?
If you maintain this skill, you can automatically optimize it using the tessl CLI to improve its score:
npx tessl skill review --optimize ./path/to/skillValidation for skill structure
Discovery
100%Based on the skill's description, can an agent find and select it at the right time? Clear, specific descriptions lead to better discovery.
This is a well-crafted skill description that excels across all dimensions. It clearly specifies the concrete action (creating Rails concerns with TDD), provides comprehensive trigger terms that users would naturally use, and explicitly states both what the skill does and when to use it. The Rails-specific focus with concern/mixin terminology makes it highly distinctive.
| Dimension | Reasoning | Score |
|---|---|---|
Specificity | Lists multiple specific concrete actions: 'Creates Rails concerns', 'shared behavior across models or controllers', 'with TDD', 'extracting shared code', 'creating reusable modules', 'DRYing up models/controllers'. | 3 / 3 |
Completeness | Clearly answers both what ('Creates Rails concerns for shared behavior across models or controllers with TDD') and when ('Use when extracting shared code, creating reusable modules, DRYing up models/controllers, or when user mentions concerns, modules, mixins, or shared behavior'). | 3 / 3 |
Trigger Term Quality | Excellent coverage of natural terms users would say: 'concerns', 'modules', 'mixins', 'shared behavior', 'DRYing up', 'extracting shared code', 'reusable modules', 'models/controllers'. | 3 / 3 |
Distinctiveness Conflict Risk | Clear niche focused specifically on Rails concerns with distinct triggers like 'concerns', 'mixins', 'shared behavior' that are unlikely to conflict with general Rails or Ruby skills. | 3 / 3 |
Total | 12 / 12 Passed |
Implementation
77%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 skill with excellent TDD workflow clarity and fully executable code examples. The main weakness is verbosity - it includes more patterns than necessary and some explanatory content about when to use concerns that experienced Rails developers don't need. The content would benefit from being split into a leaner main file with patterns in a separate reference.
Suggestions
Move the 5 'Common Concern Patterns' to a separate PATTERNS.md file and reference it from the main skill
Trim the 'When to Use Concerns' section - Claude knows Rails conventions; a brief 'Avoid single-use or god concerns' note suffices
Reduce redundancy between the two spec approaches (test class vs actual model) - pick one as primary, mention the other briefly
| Dimension | Reasoning | Score |
|---|---|---|
Conciseness | The skill is reasonably efficient but includes some redundancy - multiple similar concern patterns (5 patterns) when 2-3 would suffice, and the 'When to Use Concerns' section explains concepts Rails developers already know. The content could be tightened by ~30%. | 2 / 3 |
Actionability | Excellent executable code throughout - all examples are complete, copy-paste ready Ruby code with proper module structure, RSpec syntax, and realistic implementations. The patterns show real-world usage with actual method bodies. | 3 / 3 |
Workflow Clarity | Clear 4-step TDD workflow (RED → confirm RED → implement → GREEN) with explicit validation checkpoints. Each step includes the exact command to run and what to expect. The checklist at the end provides additional verification. | 3 / 3 |
Progressive Disclosure | Content is well-structured with clear sections, but it's a monolithic file that could benefit from splitting. The 5 common patterns section could be a separate PATTERNS.md reference, keeping SKILL.md focused on the core workflow. | 2 / 3 |
Total | 10 / 12 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.
Validation — 10 / 11 Passed
Validation for skill structure
| Criteria | Description | Result |
|---|---|---|
allowed_tools_field | 'allowed-tools' contains unusual tool name(s) | Warning |
Total | 10 / 11 Passed | |
- Reviewed
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