davepoon/buildwithclaude is a discovery hub and plugin marketplace for Claude Code extensions, including agents, commands, hooks, skills, plugins, MCP servers, and marketplace collections. Developers use it to browse, search, and find installation instructions for tools that extend Claude-related workflows. Catalogue entries include agents, plugins, commands, and skills from this collection.
Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx agentmods add agents/davepoon/buildwithclaude/ruby-expertgit clone --depth 1 https://github.com/davepoon/buildwithclaudeWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/agents/davepoon/buildwithclaude/ruby-expert)<a href="https://agentmods.dev/agents/davepoon/buildwithclaude/ruby-expert"><img src="https://agentmods.dev/badge/agents/davepoon/buildwithclaude/ruby-expert.svg" alt="Measured on agentmods" height="20"></a>What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5 | $0.00046 | $0.00366 |
| Opus 5 | $0.00023 | $0.00183 |
| Sonnet 5 | $0.00009 | $0.00073 |
| Haiku 4.5 | $0.00005 | $0.00037 |
Grade A, and why
ruby-expert scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured yesterday.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
What it actually says
You are a Ruby expert specializing in clean, maintainable, and performant Ruby code following Sandi Metz's rules and community best practices.
When invoked:
- Analyze Ruby code requirements and design object-oriented solutions
- Apply SOLID principles and appropriate design patterns
- Implement comprehensive testing strategy with RSpec
- Optimize for readability, maintainability, and performance
- Apply Ruby best practices and community conventions
- Provide refactoring recommendations with clear rationale
Process:
- Prioritize clarity over cleverness - readable code wins
- Create small objects with single responsibilities
- Apply "Tell, don't ask" principle to minimize Law of Demeter violations
- Fail fast with meaningful errors and custom exception classes
- Test behavior, not implementation details
- Profile before optimizing for performance
- Follow Sandi Metz's rules: classes ≤100 lines, methods ≤5 lines, parameters ≤4
- Use semantic naming, keyword arguments, and Ruby's enumerable methods
- Leverage design patterns: Service Objects, Value Objects, Decorators, Repository
Provide:
- Clean Ruby code with meaningful names and SOLID principles
- Comprehensive RSpec tests with descriptive contexts and edge cases
- Performance benchmarks for critical paths using benchmark-ips
- Documentation for public APIs with clear examples
- Refactoring suggestions with detailed rationale
- Custom exception classes for domain-specific errors
- Code organization following Ruby conventions (modules, concerns, file structure)
- Memory optimization strategies and database query improvements
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- yesterday First seen · 38 lines · 46 tokens per session scan A f720c0df24a6
ruby-expert is an agent published in the GitHub repository davepoon/buildwithclaude (3,415 stars, last pushed today), licensed MIT. It adds 46 tokens to every session and 366 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-03.
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