Borrowing it
Nothing to install: this file belongs to phase-rs/phase. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.
curl -O https://raw.githubusercontent.com/phase-rs/phase/main/.claude/skills/add-engine-effect/SKILL.mdgit clone --depth 1 https://github.com/phase-rs/phaseWrote 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/phase-rs/phase/add-engine-effect)<a href="https://agentmods.dev/skills/phase-rs/phase/add-engine-effect"><img src="https://agentmods.dev/badge/skills/phase-rs/phase/add-engine-effect/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/phase-rs/phase/add-engine-effect"><img src="https://agentmods.dev/badge/skills/phase-rs/phase/add-engine-effect.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 | $0.00039 | $0.05871 |
| Opus 5.5 | $0.00016 | $0.02348 |
| Sonnet 5.5 | $0.00008 | $0.01174 |
| Haiku 4.5 | $0.00004 | $0.00587 |
Grade A, and why
add-engine-effect 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 today.
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 — 349 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Adding a New Effect to the Engine
This is the authoritative checklist for adding a new effect (mechanic, keyword action, etc.) to the phase.rs engine. Every step has a file path and a what to do. Missing any step causes silent failures — effects parse but don't resolve, resolve but don't target, target but don't animate, etc.
Before you start: Read the existing effect most similar to yours. Trace it through every file below. This is how you learn the patterns — not by guessing.
CR Verification Rule: Every CR number in annotations MUST be verified by grepping
docs/MagicCompRules.txtbefore writing. Do NOT rely on memory — 701.x and 702.x numbers are arbitrary sequential assignments that LLMs consistently hallucinate. Rungrep -n "^701.21" docs/MagicCompRules.txt(etc.) for every number. If you cannot find it, do not write the annotation.
Design Philosophy — Composability Over Completeness
The single most important principle: An effect should do ONE thing. Multi-step card abilities are composed from chains of single-purpose effects linked by sub_ability.
Compose, don't monolith
When a card says "Search your library for a creature card, reveal it, put it into your hand, then shuffle your library," that's four effects composed:
SearchLibrary { filter, count, reveal }— find the cardChangeZone { destination: Hand }— put it into hand (injected as sub_ability)Shuffle {}— shuffle library (parsed from ", then shuffle")
Each is a reusable building block. SearchLibrary works for tutors, ChangeZone works for bounce/exile/reanimate, Shuffle works independently. The composition unlocks hundreds of cards, not just one.
Anti-pattern: Creating Effect::SearchAndPutInHandAndShuffle — handles exactly one card template, can't be recomposed.
Building blocks unlock future cards
Before implementing a specific card's text, ask: "What is the general pattern here?" Recent examples from this codebase:
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.
- today Changed f79cb68a8b08
- 9d ago Changed 6ff716a3c2d5
- 2mo ago First seen · 349 lines · 39 tokens per session scan A 49b8caa366a2
add-engine-effect is a skill published in the GitHub repository phase-rs/phase (312 stars, last pushed today), licensed Apache-2.0. It adds 39 tokens to every session and 5,871 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 2026-08-30.
Other skills, from other repositories
testing-rules
Testing standards — frameworks, the testable-logic trigger, golden/snapshot rules, mocking rules, and the test-author → testing-reviewer pipeline. Load for /add-tests and any change that touches testable logic.
author-contract
Shared write-side contract every domain AUTHOR imports — smallest-diff implementation, ground-first, validation gates, tests-are-blocking, and never-approve-your-own-work. The write-side mirror of token-efficiency. Load at the start of any implementation task.
coding-standards
General repo rules enforced by ESLint/TypeScript/CI — PRs-only, never bypass lint, import ordering, type imports, path privacy, commit format. Load for any code change.
anarlog
Query Anarlog meetings, notes, summaries, transcripts, participants, action items, and recurring history, or import a local recording. Use when a user asks about their Anarlog meeting data or needs meeting context for another task.
graphify-windows
Turn any folder of files into a navigable knowledge graph with community detection, an honest audit trail, and three outputs: interactive HTML, GraphRAG-ready JSON, and a plain-language GRAPHREPORT.md.
lessons
How to propose and query distilled lessons (the experiential memory). Only project-steward persists; every other agent proposes/queries. Use when you discover a durable lesson or need prior experience for the current task.