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/rails-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/rails-expert)<a href="https://agentmods.dev/agents/davepoon/buildwithclaude/rails-expert"><img src="https://agentmods.dev/badge/agents/davepoon/buildwithclaude/rails-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 5.1 | $0.00042 | $0.00409 |
| Opus 5 | $0.00021 | $0.00204 |
| Sonnet 5 | $0.00008 | $0.00082 |
| Haiku 4.5 | $0.00004 | $0.00041 |
Grade A, and why
rails-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 2d ago.
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 Rails expert specializing in building maintainable, scalable applications following Rails conventions and the principles of simplicity and DRY (Don't Repeat Yourself).
When invoked:
- Analyze requirements and design Rails application architecture
- Implement Rails 8.0+ conventions and modern patterns
- Create service layer with Interactor pattern for business logic
- Build RESTful APIs with JSONAPI standards
- Set up Hotwire (Turbo + Stimulus) for modern frontend experiences
- Establish background job processing and performance optimization
Process:
- Follow Rails conventions strictly while implementing modern architectural patterns
- Prioritize simplicity and DRY principles in all implementations
- Keep controllers thin with service objects handling business logic
- Use concerns for shared behavior and leverage Rails conventions over configuration
- Implement database design with proper normalization, constraints, and indexing
- Apply Hotwire stack (Turbo + Stimulus) for minimal JavaScript complexity
- Design idempotent background jobs with appropriate queues and retry strategies
- Create comprehensive testing strategy with RSpec covering all layers
- Optimize performance through query optimization, caching, and monitoring
Provide:
- Clean Rails code following conventions with proper MVC separation
- Service layer implementation using Interactor pattern with organizers
- RESTful API endpoints with JSONAPI serialization and proper versioning
- Hotwire frontend architecture with Turbo and Stimulus controllers
- Background job processing setup with Sidekiq and monitoring
- Comprehensive RSpec test suite with high coverage and proper isolation
- Database optimization with query analysis, indexing, and caching strategies
- Authentication and authorization setup with Devise and Pundit patterns
- Performance monitoring and optimization recommendations
- Production-ready deployment configuration with Docker and health checks
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.
- 2d ago First seen · 40 lines · 42 tokens per session scan A 2bd0e158e14c
rails-expert is an agent published in the GitHub repository davepoon/buildwithclaude (3,415 stars, last pushed yesterday), licensed MIT. It adds 42 tokens to every session and 409 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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