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 majiayu000/spellbook --skill web-artifacts-buildergit clone --depth 1 https://github.com/majiayu000/spellbookWrote 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/majiayu000/spellbook/web-artifacts-builder)<a href="https://agentmods.dev/skills/majiayu000/spellbook/web-artifacts-builder"><img src="https://agentmods.dev/badge/skills/majiayu000/spellbook/web-artifacts-builder.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 | $0.00050 | $0.00677 |
| Opus 5 | $0.00025 | $0.00338 |
| Sonnet 5 | $0.00010 | $0.00135 |
| Haiku 4.5 | $0.00005 | $0.00068 |
Grade A, and why
web-artifacts-builder 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 4d 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.
This is a copy
94% identical to web-artifacts-builder — 8 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.
How it starts
The opening of the file, as written. The whole thing — 74 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Web Artifacts Builder Skill
To build powerful frontend claude.ai artifacts, follow these steps:
- Initialize the frontend repo using
scripts/init-artifact.sh - Develop your artifact by editing the generated code
- Bundle all code into a single HTML file using
scripts/bundle-artifact.sh - Display artifact to user
- (Optional) Test the artifact
Stack: React 18 + TypeScript + Vite + Parcel (bundling) + Tailwind CSS + shadcn/ui
Design & Style Guidelines
VERY IMPORTANT: To avoid what is often referred to as "AI slop", avoid using excessive centered layouts, purple gradients, uniform rounded corners, and Inter font.
Quick Start
Step 1: Initialize Project
Run the initialization script to create a new React project:
bash scripts/init-artifact.sh <project-name>
cd <project-name>
This creates a fully configured project with:
- ✅ React + TypeScript (via Vite)
- ✅ Tailwind CSS 3.4.1 with shadcn/ui theming system
- ✅ Path aliases (
@/) configured - ✅ Starter structure for shadcn/ui-style components
- ✅ Parcel configured for bundling (via .parcelrc)
- ✅ Node 18+ compatibility (auto-detects and pins Vite version)
Step 2: Develop Your Artifact
To build the artifact, edit the generated files. See Common Development Tasks below for guidance.
Step 3: Bundle to Single HTML File
To bundle the React app into a single HTML artifact:
bash scripts/bundle-artifact.sh
This creates bundle.html - a self-contained artifact with all JavaScript, CSS, and dependencies inlined. This file can be directly shared in Claude conversations as an artifact.
Requirements: Your project must have an index.html in the root directory.
What the script does:
- Installs bundling dependencies (parcel, @parcel/config-default, parcel-resolver-tspaths, html-inline)
- Creates
.parcelrcconfig with path alias support - Builds with Parcel (no source maps)
- Inlines all assets into single HTML using html-inline
Step 4: Share Artifact with User
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.
- 4d ago First seen · 74 lines · 50 tokens per session scan A 0018792278a1
web-artifacts-builder is a skill published in the GitHub repository majiayu000/spellbook (276 stars, last pushed 3d ago), licensed MIT. It adds 50 tokens to every session and 677 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it A with 0 findings. It is 94% identical to web-artifacts-builder, differing in 8 lines, and is treated as a copy.
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