fast-typescript-check

fast-typescript-check is a skill for Claude Code, Codex from internet-development/www-sacred. It costs 84 tokens per session (4,151 once invoked), scanned A, original, MIT.

Performance and type-checking guidelines for the www-sacred React component library. Type-checking checks whether TypeScript code uses types correctly, while runtime performance concerns how much work the app does while running.

In plain words
What is it for?
Use them when changing ASCII or canvas animations, loaders and small games, or when checking whether a change introduces TypeScript or runtime slowdowns.
Why use it?
They help prevent slower compiler checks and unnecessary work in animated components. The guidance focuses on the project's components that update repeatedly with browser animation frames.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one. Also seen: mentions AGENTS.md.

Good fit Use them when changing ASCII or canvas animations, loaders and small games, or when checking whether a change introduces TypeScript or runtime slowdowns.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/internet-development/www-sacred/fast-typescript-check
About the project

SRCL is an open-source React component and styling repository for building web, desktop, and static applications with terminal-inspired visuals. Developers use its reusable components and design system when creating interfaces with monospace typography and related styling.

internet-development/www-sacred · 1,556 stars · on GitHub · sacred.computer

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 internet-development/www-sacred --skill fast-typescript-check
Clone the repo
git clone --depth 1 https://github.com/internet-development/www-sacred

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 fast-typescript-check

README.md
[![agentmods](https://agentmods.dev/badge/skills/internet-development/www-sacred/fast-typescript-check.svg)](https://agentmods.dev/skills/internet-development/www-sacred/fast-typescript-check)
Your own site
<a href="https://agentmods.dev/skills/internet-development/www-sacred/fast-typescript-check"><img src="https://agentmods.dev/badge/skills/internet-development/www-sacred/fast-typescript-check.svg" alt="Measured on agentmods" height="20"></a>
Per session 84 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 4,151 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. 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: 6 findings, 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 MCP Rug Pull · line 225
    npx commands without a version suffix (e.g. @1.0.0) create a rug-pull risk if the upstream server is compromised and publishes a malicious update.
    Fix: Pin the version: npx @scope/[email protected]
  • medium MCP Rug Pull · line 235
    npx commands without a version suffix (e.g. @1.0.0) create a rug-pull risk if the upstream server is compromised and publishes a malicious update.
    Fix: Pin the version: npx @scope/[email protected]
  • medium MCP Rug Pull · line 236
    npx commands without a version suffix (e.g. @1.0.0) create a rug-pull risk if the upstream server is compromised and publishes a malicious update.
    Fix: Pin the version: npx @scope/[email protected]
  • medium MCP Rug Pull · line 237
    npx commands without a version suffix (e.g. @1.0.0) create a rug-pull risk if the upstream server is compromised and publishes a malicious update.
    Fix: Pin the version: npx @scope/[email protected]
  • medium MCP Rug Pull · line 238
    npx commands without a version suffix (e.g. @1.0.0) create a rug-pull risk if the upstream server is compromised and publishes a malicious update.
    Fix: Pin the version: npx @scope/[email protected]
  • medium MCP Rug Pull · line 237
    npx commands without a version suffix (e.g. @1.0.0) create a rug-pull risk if the upstream server is compromised and publishes a malicious update.
    Fix: Pin the version: npx @scope/[email protected]
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 $0.00084 $0.04151
Opus 5 $0.00042 $0.02076
Sonnet 5 $0.00017 $0.00830
Haiku 4.5 $0.00008 $0.00415

Measured 8d ago against content hash e41da8c01978, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-07, from the pricing page.

Security

Grade A, and why

fast-typescript-check 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.

skills/fast-typescript-check/SKILL.md · 281 lines

How it starts

The opening of the file, as written. The whole thing — 281 lines — stays where its author put it; the contents beside it link to each section on GitHub.

fast-typescript-check

A performance discipline for www-sacred. Every rule here is justified against this codebase: either fewer CPU cycles in the components that actually run a render loop, or faster tsc --noEmit. Nothing is cosmetic, and nothing references machinery this repo does not have.

What runs hot here

This is not a game engine. There is no THREE.js, no physics, no 60fps simulation of a world. The only per-frame code is the ASCII/canvas animation family, all driven by requestAnimationFrame:

  • components/ASCIICanvas.tsx — animated ASCII art in a <pre> of per-cell <span> elements
  • components/MatrixLoader.tsx — falling-glyph matrix effect
  • components/CanvasSnake.tsx, components/DOMSnake.tsx, components/CanvasPlatformer.tsx — interactive games
  • components/examples/OneLineLoaders.tsx, components/BarLoader.tsx, components/BlockLoader.tsx, components/BarProgress.tsx — spinners

components/ASCIICanvas.tsx is the reference implementation. It already follows most of Part 1: a pre-allocated span grid, DOM diffing against previousCharsRef / previousColorsRef, refs cached into locals before the loop, an indexed for, guarded property writes, and an IntersectionObserver that stops the loop when the element scrolls off-screen. When you write or review an animation component, hold it against that file.

Everything else in the repo — the static React components, the Simulacrum CLI framework under scripts/cli/lib/*, the Python mirror — runs once per interaction, not per frame. Part 1 does not apply there; Part 2 (compiler) does.

Conventions

These match what the repo already does. Follow them; do not invent new ones.

  • Comments use //NOTE(jimmylee): (no space after //, no @) in TS/JS, # NOTE(jimmylee): in Python. Comment the why, never the what. If the code reads clearly, delete the comment. Spell names out — candidateCount, not cnt; previousColors, not pc. A clear name removes the need for a comment.
  • This repo does not use a __private prefix. Module-private state is plain const; React-internal state is refs. Don't introduce a naming scheme the rest of the codebase doesn't share.
  • The Simulacrum framework is zero-dependency TypeScript, run via tsx with no build step. Do not import that Node-only code (it uses process.stdout) from React.

Read the full file on GitHub · 281 lines

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. 8d ago First seen · 281 lines · 84 tokens per session scan A e41da8c01978

Subscribe to this mod's changes

fast-typescript-check is a skill published in the GitHub repository internet-development/www-sacred (1,556 stars, last pushed yesterday), licensed MIT. It adds 84 tokens to every session and 4,151 once invoked, about $0.0004 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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