wasm

wasm is a skill for Claude Code from TheBeardedBearSAS/claude-craft. It costs 43 tokens per session (479 once invoked), scanned A, original, MIT.

A guide to using WebAssembly, a portable format for running compiled code in browsers, servers, edge platforms, and embedded devices. It covers WASI, the WebAssembly system interface, and components built from Rust, Go, C++, or similar languages.

In plain words
What is it for?
Use it when compiling modules to WebAssembly, running them with WASI, composing typed components, or deploying them to an edge runtime.
Why use it?
It explains how code from different languages can run in environments that support WebAssembly. This can help with browser, edge, server-plugin, and embedded workloads.

Skill for Claude Code

Written for Claude Code: context: fork in frontmatter.

Part of the claude-craft plugin — 56 skills, 94 commands, 47 agents, 5 hooks shipped together

Good fit Use it when compiling modules to WebAssembly, running them with WASI, composing typed components, or deploying them to an edge runtime.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/thebeardedbearsas/claude-craft/wasm
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.

Any agent
npx skills add TheBeardedBearSAS/claude-craft --skill wasm
Clone the repo
git clone --depth 1 https://github.com/TheBeardedBearSAS/claude-craft

Made for: Claude Code.

Or install claude-craft, the plugin that ships this one along with the rest of its 56 skills, 94 commands, 47 agents, 5 hooks.

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 wasm

README.md
[![agentmods](https://agentmods.dev/badge/skills/thebeardedbearsas/claude-craft/wasm/github.svg)](https://agentmods.dev/skills/thebeardedbearsas/claude-craft/wasm)
Your own site
<a href="https://agentmods.dev/skills/thebeardedbearsas/claude-craft/wasm"><img src="https://agentmods.dev/badge/skills/thebeardedbearsas/claude-craft/wasm/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.

agentmods 80×15 button for wasm

Your own site · 80×15
<a href="https://agentmods.dev/skills/thebeardedbearsas/claude-craft/wasm"><img src="https://agentmods.dev/badge/skills/thebeardedbearsas/claude-craft/wasm.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 43 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 479 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 1 finding. A grade says what 26 rules found in the file — not that it is safe. Third-party audits
  • NVIDIA SkillSpector warn 7 Sept 2026
SkillSpector: 1 finding, up to medium

These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →

  • medium Agent Snooping · line 77
    Skill enumerates or reads other installed skills. Access to other skills' SKILL.md files or the skills directory reveals prompt instructions, capabilities, and secrets that should be invisible to peer skills.
    Fix: Remove all code or instructions that list or read other skills' files or directories. Skills should operate independently; cross-skill access is a privilege escalation.
How audits are shown
Origin original 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 5.1 $0.00043 $0.00479
Opus 5 $0.00022 $0.00239
Sonnet 5 $0.00009 $0.00096
Haiku 4.5 $0.00004 $0.00048

Measured 5d ago against content hash 460ebb891d09, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-08, from the pricing page.

Security

Grade A, and why

wasm scanned grade A with 1 finding 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.

Makes network callslowCapability

Not a fault in itself. Listed so you know the mod talks to something, and to what.

async fetch(req) {
.claude/skills/wasm/SKILL.md · 78 lines

What it actually says

WebAssembly (WASM) — Component Model, WASI

WASM pour performance critique, polyglot runtime, edge computing.

Use Cases

Browser — Crypto, image (Figma, Google Earth)
Edge — Cloudflare Workers, Fastly
Server — Plugins sandboxés (Envoy)
Embedded — IoT, automotive

Compilation

Rustwasm-pack (~50KB, perf)
GoGOOS=js GOARCH=wasm (~2MB)
C/C++ — Emscripten (legacy)
AssemblyScript — TypeScript-like

Rust to WASM

use wasm_bindgen::prelude::*;
#[wasm_bindgen] pub fn add(a: i32, b: i32) -> i32 { a + b }
wasm-pack build --target web
import init, { add } from './pkg/wasm.js';
await init(); add(2, 3);

WASI (System Interface)

rustc --target wasm32-wasi main.rs -o app.wasm
wasmtime app.wasm

Component Model

interface math { add: func(a: s32, b: s32) -> s32 }

Compose Rust/Go/C++ modules typés.

Edge (Cloudflare)

import wasm from './processor.wasm';
export default {
  async fetch(req) {
    const inst = await WebAssembly.instantiate(wasm);
    return new Response(inst.exports.process(req.body));
  }
};

Runtimes

Wasmtime — Fast, WASI
Wasmer — Universal
WasmEdge — Edge, K8s


Voir @.claude/skills/edge-computing/SKILL.md

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 · 78 lines · 0 tokens per session scan A 460ebb891d09

Subscribe to this mod's changes

wasm is a skill published in the GitHub repository TheBeardedBearSAS/claude-craft (105 stars, last pushed 6d ago), licensed MIT. It adds 43 tokens to every session and 479 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it A with 1 finding (makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-03.

Related

Other skills, from other repositories