bun-runtime

bun-runtime is a skill for Claude Code, Codex from sifxprime/kodelyth-ecc. It costs 34 tokens per session (663 once invoked), scanned A, a copy of bun-runtime, MIT.

A JavaScript runtime and toolkit that can run code, install packages, bundle applications, and run tests. It is an alternative to Node.js, with guidance for choosing between them and deploying Bun on Vercel.

In plain words
What is it for?
Use it when starting a JavaScript or TypeScript project with Bun, migrating from Node.js, writing Bun scripts or tests, or configuring Bun for deployment.
Why use it?
It helps teams decide whether Bun fits their project and move existing Node.js workflows to Bun without guessing which commands, lockfiles, or dependencies need attention.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Needs its repository: it runs a file that does not travel with it, so clone the repository first. The line is bun src/index.ts.

Good fit Use it when starting a JavaScript or TypeScript project with Bun, migrating from Node.js, writing Bun scripts or tests, or configuring Bun for deployment.

Compare 6 skills from other repositories ↓
Install

Getting it into your agent

It runs from inside its repository, so the clone comes first — what it calls does not travel with the file alone.

Clone the repo
git clone --depth 1 https://github.com/sifxprime/kodelyth-ecc
agentmods
npx agentmods add skills/sifxprime/kodelyth-ecc/bun-runtime

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 bun-runtime

README.md
[![agentmods](https://agentmods.dev/badge/skills/sifxprime/kodelyth-ecc/bun-runtime/github.svg)](https://agentmods.dev/skills/sifxprime/kodelyth-ecc/bun-runtime)
Your own site
<a href="https://agentmods.dev/skills/sifxprime/kodelyth-ecc/bun-runtime"><img src="https://agentmods.dev/badge/skills/sifxprime/kodelyth-ecc/bun-runtime/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 bun-runtime

Your own site · 80×15
<a href="https://agentmods.dev/skills/sifxprime/kodelyth-ecc/bun-runtime"><img src="https://agentmods.dev/badge/skills/sifxprime/kodelyth-ecc/bun-runtime.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 34 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 663 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.
Origin 100% copy Near-identical to another mod 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 $0.00034 $0.00663
Opus 5.5 $0.00014 $0.00265
Sonnet 5.5 $0.00007 $0.00133
Haiku 4.5 $0.00003 $0.00066

Measured 1mo ago against content hash 2929d1f22796, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

bun-runtime 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 1mo 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.

fetch(req) {
Origin

This is a copy

100% identical to bun-runtime — 23 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.

skills/bun-runtime/SKILL.md · 85 lines

How it starts

The opening of the file, as written. The whole thing — 85 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Bun Runtime

Bun is a fast all-in-one JavaScript runtime and toolkit: runtime, package manager, bundler, and test runner.

When to Use

  • Prefer Bun for: new JS/TS projects, scripts where install/run speed matters, Vercel deployments with Bun runtime, and when you want a single toolchain (run + install + test + build).
  • Prefer Node for: maximum ecosystem compatibility, legacy tooling that assumes Node, or when a dependency has known Bun issues.

Use when: adopting Bun, migrating from Node, writing or debugging Bun scripts/tests, or configuring Bun on Vercel or other platforms.

How It Works

  • Runtime: Drop-in Node-compatible runtime (built on JavaScriptCore, implemented in Zig).
  • Package manager: bun install is significantly faster than npm/yarn. Lockfile is bun.lock (text) by default in current Bun; older versions used bun.lockb (binary).
  • Bundler: Built-in bundler and transpiler for apps and libraries.
  • Test runner: Built-in bun test with Jest-like API.

Migration from Node: Replace node script.js with bun run script.js or bun script.js. Run bun install in place of npm install; most packages work. Use bun run for npm scripts; bun x for npx-style one-off runs. Node built-ins are supported; prefer Bun APIs where they exist for better performance.

Vercel: Set runtime to Bun in project settings. Build: bun run build or bun build ./src/index.ts --outdir=dist. Install: bun install --frozen-lockfile for reproducible deploys.

Examples

Run and install

# Install dependencies (creates/updates bun.lock or bun.lockb)
bun install

# Run a script or file
bun run dev
bun run src/index.ts
bun src/index.ts

Scripts and env

bun run --env-file=.env dev
FOO=bar bun run script.ts

Testing

bun test
bun test --watch
// test/example.test.ts
import { expect, test } from "bun:test";

test("add", () => {
  expect(1 + 2).toBe(3);
});

Runtime API

Read the full file on GitHub · 85 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. 1mo ago First seen · 85 lines · 34 tokens per session scan A 2929d1f22796

Subscribe to this mod's changes

bun-runtime is a skill published in the GitHub repository sifxprime/kodelyth-ecc (11 stars, last pushed 12d ago), licensed MIT. It adds 34 tokens to every session and 663 once invoked, about $0.0001 per session on Opus 5.5. A static security scan graded it A with 1 finding (makes network calls). It is 100% identical to bun-runtime, differing in 23 lines, and is treated as a copy.

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