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 slbug/claude-ruby-grape-rails --skill rails-contextsgit clone --depth 1 https://github.com/slbug/claude-ruby-grape-railsWrote 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/slbug/claude-ruby-grape-rails/rails-contexts)<a href="https://agentmods.dev/skills/slbug/claude-ruby-grape-rails/rails-contexts"><img src="https://agentmods.dev/badge/skills/slbug/claude-ruby-grape-rails/rails-contexts/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/slbug/claude-ruby-grape-rails/rails-contexts"><img src="https://agentmods.dev/badge/skills/slbug/claude-ruby-grape-rails/rails-contexts.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 | $0.00047 | $0.00419 |
| Opus 5.5 | $0.00019 | $0.00168 |
| Sonnet 5.5 | $0.00009 | $0.00084 |
| Haiku 4.5 | $0.00005 | $0.00042 |
Grade A, and why
rails-contexts 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
Rails Contexts
Iron Laws
- Controllers translate HTTP; they do not own business rules.
- Model callbacks should not silently trigger external side effects.
- Policy and authorization checks must be explicit at boundaries.
- Service, query, and form objects should clarify ownership, not add ceremony for its own sake.
Good Rails Boundaries
- controller or endpoint for transport concerns
- application service or command for workflow orchestration
- query object when a query grows beyond a scope or two
- policy object for authorization rules
- job only for deferred or async work
References
| Need | Reference |
|---|---|
| service / form / query / policy / serializer placement | ${CLAUDE_SKILL_DIR}/references/context-patterns.md |
| strong-params discipline | ${CLAUDE_SKILL_DIR}/references/strong-params.md |
| routing / namespacing / engine boundaries | ${CLAUDE_SKILL_DIR}/references/routing-patterns.md |
| JSON / API controller, serializer, JSON:API, JWT auth | ${CLAUDE_SKILL_DIR}/references/json-api-patterns.md |
| middleware + before-action filter patterns | ${CLAUDE_SKILL_DIR}/references/middleware-before-action-patterns.md |
| Pundit / CanCanCan + manual authorization + multi-tenant scopes | ${CLAUDE_SKILL_DIR}/references/scopes-auth.md |
Related — invoke manually if needed
- dry-rb gem patterns (validation, types, monads) →
/rb:dry-rb-patterns(dry-rb gem patterns)
What ships with it
6 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
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 · 40 lines · 47 tokens per session scan A 08694c403024
rails-contexts is a skill published in the GitHub repository slbug/claude-ruby-grape-rails (7 stars, last pushed 16d ago), licensed MIT. It adds 47 tokens to every session and 419 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 2026-09-03.
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