with-svelte

with-svelte is a skill for Claude Code, Codex from robcsaszar/frontend-kit. It costs 203 tokens per session (1,721 once invoked), scanned A, original, MIT.

A set of coding guidelines for Svelte 5 and SvelteKit, tools for building web applications with Svelte. It explains current syntax for components, state, routing, and rendering.

In plain words
What is it for?
Use it when creating, editing, reviewing, or debugging Svelte components, Svelte modules, or SvelteKit projects.
Why use it?
It helps keep Svelte code aligned with current conventions and avoids older patterns when newer ones are recommended.

Skill for Claude CodeCodex

Part of the robcsaszar-frontend-kit plugin — 4 skills shipped together

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/robcsaszar/frontend-kit/with-svelte
Any agent
npx skills add robcsaszar/frontend-kit --skill with-svelte
Clone the repo
git clone --depth 1 https://github.com/robcsaszar/frontend-kit

Made for: Claude Code, Codex.

Or install robcsaszar-frontend-kit, the plugin that ships this one along with the rest of its 4 skills.

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 with-svelte

README.md
[![agentmods](https://agentmods.dev/badge/skills/robcsaszar/frontend-kit/with-svelte.svg)](https://agentmods.dev/skills/robcsaszar/frontend-kit/with-svelte)
Your own site
<a href="https://agentmods.dev/skills/robcsaszar/frontend-kit/with-svelte"><img src="https://agentmods.dev/badge/skills/robcsaszar/frontend-kit/with-svelte.svg" alt="Measured on agentmods" height="20"></a>
Per session 203 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,721 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
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 $0.00203 $0.01721
Opus 5 $0.00102 $0.00860
Sonnet 5 $0.00041 $0.00344
Haiku 4.5 $0.00020 $0.00172

Measured 4d ago against content hash 179084bfb686, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

with-svelte 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.

skills/with-svelte/SKILL.md · 81 lines

How it starts

The opening of the file, as written. The whole thing — 81 lines — stays where its author put it; the contents beside it link to each section on GitHub.

with-svelte

Unified Svelte 5 + SvelteKit skill. This body is a router: apply the always-on core below, then READ the one reference file that matches the task before writing code. Load only the file(s) you need — not all of them.

Always-on core (every Svelte task)

Write runes-mode Svelte 5. Never reach for a legacy feature that has a modern replacement:

  • $state instead of implicit let count = 0; count += 1
  • $derived/$effect instead of $: — and prefer $derived over $effect (effects are an escape hatch; never set state inside one)
  • $props instead of export let, $$props, $$restProps
  • onclick={...} instead of on:click={...}
  • {#snippet}/{@render} instead of <slot>, $$slots, <svelte:fragment>
  • {@attach ...} instead of use:action
  • <DynamicComponent> instead of <svelte:component this={...}>; import Self instead of <svelte:self>
  • classes with $state fields instead of stores; createContext instead of setContext/getContext
  • clsx-style class arrays/objects instead of the class: directive
  • keyed {#each} — never use the index as the key

When unsure of current syntax, do not guess — confirm via the @sveltejs/mcp CLI (see references/tooling.md) and run svelte-autofixer before finalizing any component.

Routing table — READ the matching reference before writing

Task involves… MANDATORY READ
Runes$state, $derived, $effect, choosing between them references/runes-core.md
Runes$props, $bindable, reactive class fields, createSubscriber, $inspect references/runes-props.md
Runesawait in components, async reactivity, hydratable references/runes-async.md
Runes — porting Svelte 4 syntax to runes mode references/runes-migration.md
Runes — reactivity that compiles but behaves wrongly references/runes-antipatterns.md
Template{@attach}, migrating use: actions references/attachments.md
Template{#snippet} / {@render}, replacing slots references/snippets.md
Template{@html}, {@const}, {@debug}, keyed each, bind:, <svelte:window> references/template-tags.md
Components — Bits/Ark/Melt UI, web components, custom elements references/component-libraries.md
Components — forms inside components references/forms.md
Components — CSS from JS, styling children, context references/styling-context.md
Routing — file naming (+page/+layout/+error/+server), route groups, params references/routing-files.md
Routing — nested layouts, layout groups, layout data references/layouts.md
Routing+error.svelte, expected vs unexpected errors references/error-handling.md
Routing<svelte:boundary> references/error-boundary.md
Routing — SSR, hydration mismatches, browser-only work references/ssr-hydration.md
Dataload functions, server vs universal, depends references/load-functions.md
Data — form actions, progressive enhancement references/form-actions.md
Datafail() / redirect() / error() references/errors-redirects.md
Data — serialization across the boundary, invalidateAll() references/serialization-invalidation.md
Remotequery() / form() in *.remote.ts, schema validation references/remote-query-form.md
Remotecommand(), single-flight mutations, prerender(), getRequestEvent() references/remote-command-prerender.md
Deploy — adapters, Vite/pnpm build setup references/deployment-adapters.md
Deploy — publishing a Svelte library references/library-authoring.md
Deploy — PWA setup, Cloudflare/streaming gotchas references/pwa-and-cloudflare.md
Tooling — confirming syntax, looking up docs, validating/fixing code references/tooling.md

Read the full file on GitHub · 81 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. 4d ago First seen · 81 lines · 203 tokens per session scan A 179084bfb686

Subscribe to this mod's changes

with-svelte is a skill published in the GitHub repository robcsaszar/frontend-kit (1 stars, last pushed 2d ago), licensed MIT. It adds 203 tokens to every session and 1,721 once invoked, about $0.0010 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 2026-08-31.