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 ag0os/rails-dev-plugin --skill rails-stack-profilesgit clone --depth 1 https://github.com/ag0os/rails-dev-pluginWrote 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/ag0os/rails-dev-plugin/rails-stack-profiles)<a href="https://agentmods.dev/skills/ag0os/rails-dev-plugin/rails-stack-profiles"><img src="https://agentmods.dev/badge/skills/ag0os/rails-dev-plugin/rails-stack-profiles/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/ag0os/rails-dev-plugin/rails-stack-profiles"><img src="https://agentmods.dev/badge/skills/ag0os/rails-dev-plugin/rails-stack-profiles.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 | $0.00092 | $0.01227 |
| Opus 5.5 | $0.00037 | $0.00491 |
| Sonnet 5.5 | $0.00018 | $0.00245 |
| Haiku 4.5 | $0.00009 | $0.00123 |
Grade A, and why
rails-stack-profiles 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.
How it starts
The opening of the file, as written. The whole thing — 94 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Rails Stack Axes
Resolve a project's architecture once per session, as two independent binary axes. Other skills consume the resolved axes to load one flat, branch-free guidance file each — they never carry inline omakase / service-oriented conditionals.
See axis-a.md and axis-b.md for characteristic patterns and code per axis value.
The Two Axes
A project is not one of three profiles. It is one value on each of two axes:
| Axis | Values | Question it answers |
|---|---|---|
| A — logic placement | native | extracted |
Where does non-trivial business logic live? |
| B — delivery | html | api |
Does the surface render HTML or serve JSON? |
native— logic lives in models, concerns, and POROs. The Rails-omakase way. Callbacks are acceptable for simple side effects.extracted— service/command objects are the default home for non-trivial logic. Common in larger teams and complex domains.html— server-rendered views, Hotwire (Turbo + Stimulus).api— headless JSON, serializers, noapp/views/(mailer views aside).
The axes are independent. All four combinations are valid, including native + api (a Rails 8 omakase-style API-only app — a combination the old three-profile enum could not express).
The legacy names map cleanly: omakase = native + html, service-oriented = extracted + html, api-first = extracted + api.
What is NOT an axis
Test framework, test data strategy, job backend, cache store, and auth library are orthogonal project facts, not architecture axes. A project with extracted services can still use Minitest; an omakase app can run Sidekiq. Inferring these from architecture is the central mistake this restructure removes.
Detect them directly via the project-conventions fingerprint. Skills consume those fingerprint fields; they never branch on a "profile" for them.
Detecting Axis A — logic placement
| Signal | Points to |
|---|---|
app/services/ with ~5+ files |
extracted |
Custom ApplicationService / BaseService base class |
extracted |
gem "dry-monads", gem "interactor", gem "trailblazer" |
extracted |
app/services/ absent or near-empty |
native |
Domain logic in models + app/models/concerns/ |
native |
| Callbacks orchestrating multi-step workflows | native |
POROs for operations, often in app/models/ |
native |
What ships with it
2 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 · 94 lines · 92 tokens per session scan A b1b751de9dcc
rails-stack-profiles is a skill published in the GitHub repository ag0os/rails-dev-plugin (5 stars, last pushed 4mo ago), licensed MIT. It adds 92 tokens to every session and 1,227 once invoked, about $0.0004 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 2026-08-31.
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