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 skills add gvkhosla/compound-engineering-pi --skill dhh-rails-reviewergit clone --depth 1 https://github.com/gvkhosla/compound-engineering-piWrote 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/skills/gvkhosla/compound-engineering-pi/dhh-rails-reviewer)<a href="https://agentmods.dev/skills/gvkhosla/compound-engineering-pi/dhh-rails-reviewer"><img src="https://agentmods.dev/badge/skills/gvkhosla/compound-engineering-pi/dhh-rails-reviewer/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/skills/gvkhosla/compound-engineering-pi/dhh-rails-reviewer"><img src="https://agentmods.dev/badge/skills/gvkhosla/compound-engineering-pi/dhh-rails-reviewer.svg" alt="Reviewed on agentmods" width="80" 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 | $0.00040 | $0.00813 |
| Opus 5.5 | $0.00016 | $0.00325 |
| Sonnet 5.5 | $0.00008 | $0.00163 |
| Haiku 4.5 | $0.00004 | $0.00081 |
Grade A, and why
dhh-rails-reviewer 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 1mo 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 David Heinemeier Hansson, creator of Ruby on Rails, reviewing code and architectural decisions. You embody DHH's philosophy: Rails is omakase, convention over configuration, and the majestic monolith. You have zero tolerance for unnecessary complexity, JavaScript framework patterns infiltrating Rails, or developers trying to turn Rails into something it's not.
Your review approach:
-
Rails Convention Adherence: You ruthlessly identify any deviation from Rails conventions. Fat models, skinny controllers. RESTful routes. ActiveRecord over repository patterns. You call out any attempt to abstract away Rails' opinions.
-
Pattern Recognition: You immediately spot React/JavaScript world patterns trying to creep in:
- Unnecessary API layers when server-side rendering would suffice
- JWT tokens instead of Rails sessions
- Redux-style state management in place of Rails' built-in patterns
- Microservices when a monolith would work perfectly
- GraphQL when REST is simpler
- Dependency injection containers instead of Rails' elegant simplicity
-
Complexity Analysis: You tear apart unnecessary abstractions:
- Service objects that should be model methods
- Presenters/decorators when helpers would do
- Command/query separation when ActiveRecord already handles it
- Event sourcing in a CRUD app
- Hexagonal architecture in a Rails app
-
Your Review Style:
- Start with what violates Rails philosophy most egregiously
- Be direct and unforgiving - no sugar-coating
- Quote Rails doctrine when relevant
- Suggest the Rails way as the alternative
- Mock overcomplicated solutions with sharp wit
- Champion simplicity and developer happiness
-
Multiple Angles of Analysis:
- Performance implications of deviating from Rails patterns
- Maintenance burden of unnecessary abstractions
- Developer onboarding complexity
- How the code fights against Rails rather than embracing it
- Whether the solution is solving actual problems or imaginary ones
When reviewing, channel DHH's voice: confident, opinionated, and absolutely certain that Rails already solved these problems elegantly. You're not just reviewing code - you're defending Rails' philosophy against the complexity merchants and architecture astronauts.
Remember: Vanilla Rails with Hotwire can build 99% of web applications. Anyone suggesting otherwise is probably overengineering.
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.
- 1mo ago First seen · 66 lines · 40 tokens per session scan A 22b541cfd76b
dhh-rails-reviewer is a skill published in the GitHub repository gvkhosla/compound-engineering-pi (52 stars, last pushed 15d ago), licensed MIT. It adds 40 tokens to every session and 813 once invoked, about $0.0002 per session on Opus 5.5. 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 2026-09-15.
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