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 garrettw/php-arch-skills --skill infrastructure-boundariesgit clone --depth 1 https://github.com/garrettw/php-arch-skillsWrote 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/garrettw/php-arch-skills/infrastructure-boundaries)<a href="https://agentmods.dev/skills/garrettw/php-arch-skills/infrastructure-boundaries"><img src="https://agentmods.dev/badge/skills/garrettw/php-arch-skills/infrastructure-boundaries.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 | $0.00047 | $0.01645 |
| Opus 5 | $0.00023 | $0.00822 |
| Sonnet 5 | $0.00009 | $0.00329 |
| Haiku 4.5 | $0.00005 | $0.00164 |
Grade A, and why
infrastructure-boundaries 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 8d 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 — 83 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Infrastructure & Integration Boundaries in PHP
When to Use Hexagonal Architecture (and When NOT to)
Hexagonal architecture isolates the core via ports and adapters, but it is not universal. Use it for long-lived applications that need to swap infrastructure or require high test coverage. Skip it for libraries, simple CRUD APIs, or throwaway utilities.
| Use Hexagonal For | Use Simpler Patterns For |
|---|---|
| Long-lived application with evolving infrastructure | Libraries, packages, SDKs (PSR standards usually suffice) |
| Need to swap DB, broker, or external API | Fixed infrastructure, unlikely to change |
| Multiple entry points (API, CLI, events) | Single delivery channel |
| High test coverage required | Quick scripts, internal tools |
For libraries, package your code with PSR-4 autoloading and clear namespacing. Let the consumer inject dependencies. Do not add a hexagonal adapter layer for a library.
System Overview
The Infrastructure layer contains everything that speaks to the outside world: databases, search engines, APIs, message queues, and the filesystem. It implements adapters (driven and driver) that fulfill ports defined by inner layers. This skill provides the rules for keeping infrastructure concerns separated from domain logic through adapters, ports, and proper placement.
A Gateway is the classic name for exactly this seam: an object that encapsulates communication with one external system so the application knows that the call happened, not how. In modern terms a Gateway is a Port + Adapter. Name it after the business capability (PaymentGateway), never the transport or vendor (StripeHttpWrapper).
A Mapper is the companion translation object at the same seam: it converts between two representations of the same fact (domain object ↔ DTO, domain ↔ external API model) while preserving meaning. It is not a Transformer — never put business rules in a mapper. The persistence-specific instance is the Data Mapper in persistence-patterns.
What ships with it
3 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.
- 8d ago First seen · 83 lines · 47 tokens per session scan A a84037b25642
infrastructure-boundaries is a skill published in the GitHub repository garrettw/php-arch-skills (12 stars, last pushed 1mo ago), licensed MPL-2.0. It adds 47 tokens to every session and 1,645 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 2026-08-31.
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