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 architecture-migrationgit 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/architecture-migration)<a href="https://agentmods.dev/skills/garrettw/php-arch-skills/architecture-migration"><img src="https://agentmods.dev/badge/skills/garrettw/php-arch-skills/architecture-migration/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/garrettw/php-arch-skills/architecture-migration"><img src="https://agentmods.dev/badge/skills/garrettw/php-arch-skills/architecture-migration.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 | $0.00042 | $0.01182 |
| Opus 5 | $0.00021 | $0.00591 |
| Sonnet 5 | $0.00008 | $0.00236 |
| Haiku 4.5 | $0.00004 | $0.00118 |
Grade A, and why
architecture-migration 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 — 59 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Incremental Architecture Migration for PHP Apps
When to Migrate (and When NOT to)
Big-bang rewrites are risky and halt product momentum. Migrate only when actively building a feature or fixing a complex bug in an area. Do not migrate code that has not been touched in years solely for aesthetic reasons.
| Good Migration Trigger | Poor Migration Trigger |
|---|---|
| Actively building a new feature | "Cleaning up" untouched code |
| Fixing a complex bug in legacy code | Compliant refactor of inactive code |
| Exposing a web feature as an API endpoint | Preference for architecture purity |
Evolutionary, touched-area migrations using vertical slices and temporary compatibility shims. This is the Strangler Fig approach: grow new behavior alongside the legacy system, move behavior across behind seams, and remove the legacy only once it carries nothing (see strangler-fig.md). The delivery mechanics — transitional architecture, event interception, legacy mimics, diverting the flow — are catalogued in legacy-displacement-patterns.md. It is the antidote to the big-bang rewrite, which fails because replacements take too long, users can't wait for features, and much of the old behavior isn't actually wanted.
System Overview
This skill guides the process of moving PHP applications toward a cleaner architecture through incremental, touched-area migrations using vertical slices and temporary compatibility shims. When adopting layered DDD, follow this order: discover the domain, model aggregates and value objects, define ports, implement use cases, and add adapters last.
Numbered Workflows
1. Evaluating a Migration Trigger
If considering refactoring legacy code into a new architecture:
- Check the Motivation. Are you actively building a new feature in this area, fixing a complex bug, or exposing an existing web feature as an API endpoint? If yes, it is a good trigger. Proceed.
- Evaluate Complexity Fit. Is the domain complex enough to warrant full DDD? If the rules are mostly CRUD with few invariants, favor lean ORM entities over full DDD aggregates. Start simple and evolve only when needed.
- Reject Poor Triggers. Are you just doing it to "clean things up" or to fix a standard violation in code that hasn't been touched in years? If yes, halt the migration.
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.
- 8d ago First seen · 59 lines · 42 tokens per session scan A 485941293e67
architecture-migration is a skill published in the GitHub repository garrettw/php-arch-skills (12 stars, last pushed 1mo ago), licensed MPL-2.0. It adds 42 tokens to every session and 1,182 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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