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 AdamBien/airails --skill bcegit clone --depth 1 https://github.com/AdamBien/airailsWrote 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/adambien/airails/bce)<a href="https://agentmods.dev/skills/adambien/airails/bce"><img src="https://agentmods.dev/badge/skills/adambien/airails/bce/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/adambien/airails/bce"><img src="https://agentmods.dev/badge/skills/adambien/airails/bce.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector pass
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 | $0.00151 | $0.01074 |
| Opus 5.5 | $0.00060 | $0.00430 |
| Sonnet 5.5 | $0.00030 | $0.00215 |
| Haiku 4.5 | $0.00015 | $0.00107 |
Grade A, and why
bce 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 — 71 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Pattern
- structure code using the Boundary-Control-Entity (BCE/ECB) pattern
- the unit of organization is the business component (BC); each BC owns a responsibility and is composed of one or more layers
- the three layers are boundary, control, entity; each has a distinct responsibility (see layer sections below)
- do not explain the BCE pattern in generated documentation
Package / Directory Structure
- package or directory path:
[ORGANIZATION].[PROJECT].[BC].[boundary|control|entity] - the top-level package reflects the application responsibility or name
- business components are direct children of the top-level package and named after their responsibilities
- the
boundary,control,entitysegments are only allowed inside a business component - name packages after their domain responsibilities, not technical concerns
Business Components (BC)
- a BC may represent a domain concept or a shared concern; both are valid when the responsibility has a name and is reused
- a BC does not need every layer; a BC may consist of only a control layer when its responsibility is procedural and consumed by other BCs
- not every BC needs a dedicated boundary; control contents may be consumed directly when no facade is justified
- prefer a dedicated BC over the root application package when a shared concern carries domain or protocol semantics, exposes more than one operation, or is expected to grow
- reserve the root application package for trivial single-class plumbing with no business semantics and no protocol coupling
- create new BCs with minimal logic and essential fields only
Boundary Layer
- keep coarse-grained classes in the boundary
- place facades that adapt external protocols, transports, or UI events to internal operations in the boundary
- boundary classes are the only entry points called from outside the system; external actors (UI, protocols, transports, tests) never reach control or entity directly
- cross-cutting concerns that wrap an operation (transactions, authorization checks, request/response mapping) belong in the boundary, not in control or entity
What ships with it
1 file 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 Changed · +1 lines 472705feb408
- 1mo ago First seen · 70 lines · 151 tokens per session scan A e59781865e5f
bce is a skill published in the GitHub repository AdamBien/airails (59 stars, last pushed 4d ago), licensed MIT. It adds 151 tokens to every session and 1,074 once invoked, about $0.0006 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 2026-08-30.
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