# Andrew Kane Gem Writer

> This skill should be used when writing Ruby gems following Andrew Kane's proven patterns and philosophy. It applies when creating new Ruby gems, refactoring existing gems, designing gem APIs, or when clean, minimal, production-ready Ruby library code is needed. Triggers on requests like "create a gem", "write a Ruby library", "design a gem API", or mentions of Andrew Kane's style.

- **Type:** Skill
- **Install:** `agentstack add skill-antifragiletech-antifragile-claude-code-andrew-kane-gem-writer`
- **Verified:** Yes — security-reviewed for prompt injection and unsafe behavior
- **Seller:** [AntifragileTech](https://agentstack.voostack.com/s/antifragiletech)
- **Installs:** 0
- **Category:** [Agent Skills](https://agentstack.voostack.com/c/agent-skills)
- **Latest version:** 0.1.0
- **License:** MIT
- **Upstream author:** [AntifragileTech](https://github.com/AntifragileTech)
- **Source:** https://github.com/AntifragileTech/antifragile-claude-code/tree/master/assets/skills/dev/andrew-kane-gem-writer

## Install

```sh
agentstack add skill-antifragiletech-antifragile-claude-code-andrew-kane-gem-writer
```

Requires the [AgentStack CLI](https://agentstack.voostack.com/docs/cli). Works with Claude Code, Cursor, and any MCP-compatible agent.

## About

# Andrew Kane Gem Writer

Write Ruby gems following Andrew Kane's battle-tested patterns from 100+ gems with 374M+ downloads (Searchkick, PgHero, Chartkick, Strong Migrations, Lockbox, Ahoy, Blazer, Groupdate, Neighbor, Blind Index).

## Core Philosophy

**Simplicity over cleverness.** Zero or minimal dependencies. Explicit code over metaprogramming. Rails integration without Rails coupling. Every pattern serves production use cases.

## Entry Point Structure

Every gem follows this exact pattern in `lib/gemname.rb`:

```ruby
# 1. Dependencies (stdlib preferred)
require "forwardable"

# 2. Internal modules
require_relative "gemname/model"
require_relative "gemname/version"

# 3. Conditional Rails (CRITICAL - never require Rails directly)
require_relative "gemname/railtie" if defined?(Rails)

# 4. Module with config and errors
module GemName
  class Error = 3.1"
  spec.files = Dir["*.{md,txt}", "{lib}/**/*"]
  spec.require_path = "lib"
  # NO add_dependency lines - dev deps go in Gemfile
end
```

## Anti-Patterns to Avoid

- `method_missing` (use `define_method` instead)
- Configuration objects (use class accessors)
- `@@class_variables` (use `class << self`)
- Requiring Rails gems directly
- Many runtime dependencies
- Committing Gemfile.lock in gems
- RSpec (use Minitest)
- Heavy DSLs (prefer explicit Ruby)

## Reference Files

For deeper patterns, see:
- **[references/module-organization.md](references/module-organization.md)** - Directory layouts, method decomposition
- **[references/rails-integration.md](references/rails-integration.md)** - Railtie, Engine, on_load patterns
- **[references/database-adapters.md](references/database-adapters.md)** - Multi-database support patterns
- **[references/testing-patterns.md](references/testing-patterns.md)** - Multi-version testing, CI setup
- **[references/resources.md](references/resources.md)** - Links to Kane's repos and articles

## Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

- **Author:** [AntifragileTech](https://github.com/AntifragileTech)
- **Source:** [AntifragileTech/antifragile-claude-code](https://github.com/AntifragileTech/antifragile-claude-code)
- **License:** MIT

Install and usage instructions live in the source repository linked above.

## Pricing

- **Free** — Free

## Security capabilities

Automated source analysis of v0.1.0 — what this tool can access:

- **Network access:** no
- **Filesystem access:** no
- **Shell / process execution:** no
- **Environment & secrets:** no
- **Dynamic code execution:** no

*"Yes" means the capability is present in the source — more access means more to trust, not that it is unsafe.*


## Versions

- **0.1.0** — security scan: passed — Imported from the upstream source.

## Links

- Listing page: https://agentstack.voostack.com/l/skill-antifragiletech-antifragile-claude-code-andrew-kane-gem-writer
- Seller: https://agentstack.voostack.com/s/antifragiletech
- Browse the marketplace: https://agentstack.voostack.com/browse

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Listed on AgentStack — the marketplace for AI agent skills and MCP servers. Every listing is security-reviewed. Creators keep 70%.