sw-best-practices

sw-best-practices is a skill for Claude Code, Codex from dtyq/magic. It costs 47 tokens per session (2,838 once invoked), scanned A, original, no licence file.

A set of practical rules for the Magic Web service worker, a browser script that can cache resources and handle some requests. It covers resource grouping, read-only API caching, request labels, emergency shutdown or replacement of the worker, and rollback settings.

In plain words
What is it for?
Use it when changing service-worker caching, request handling, /sw.js takeover behavior, or emergency rollback environment variables.
Why use it?
It reduces the risk of stale cached files, unsafe worker changes, or difficult emergency rollbacks. It keeps service-worker changes aligned with the current implementation.

Skill for Claude CodeCodex

Install

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.

agentmods
npx agentmods add skills/dtyq/magic/sw-best-practices
Any agent
npx skills add dtyq/magic --skill sw-best-practices
Clone the repo
git clone --depth 1 https://github.com/dtyq/magic

Made for: Claude Code, Codex.

Wrote 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.

agentmods badge for sw-best-practices

README.md
[![agentmods](https://agentmods.dev/badge/skills/dtyq/magic/sw-best-practices.svg)](https://agentmods.dev/skills/dtyq/magic/sw-best-practices)
Your own site
<a href="https://agentmods.dev/skills/dtyq/magic/sw-best-practices"><img src="https://agentmods.dev/badge/skills/dtyq/magic/sw-best-practices.svg" alt="Measured on agentmods" height="20"></a>
Per session 47 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,838 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin unknown No closer match found in the catalogue.
Token cost

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.

ModelPer sessionOnce invoked
Fable 5 $0.00047 $0.02838
Opus 5 $0.00023 $0.01419
Sonnet 5 $0.00009 $0.00568
Haiku 4.5 $0.00005 $0.00284

Measured 5d ago against content hash 84e6625ea296, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

sw-best-practices 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 5d 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.

frontend/magic-web/.agents/skills/sw-best-practices/SKILL.md · 136 lines

The source is not reproduced here

A licence we could not identify

The repository carries a LICENSE file, but it is custom or dual enough that GitHub cannot name it and neither can this catalogue. Unknown terms are not permission, so the body is not copied here. Read the licence at the source and decide for yourself.

Read it on GitHub

Changes

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.

  1. 5d ago First seen · 136 lines · 47 tokens per session scan A 84e6625ea296

Subscribe to this mod's changes

sw-best-practices is a skill published in the GitHub repository dtyq/magic (5,015 stars, last pushed 23d ago), with no licence file. It adds 47 tokens to every session and 2,838 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 2026-08-30.

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