Agent skill · software engineering · secondsky
bun-runtime
Use for Bun runtime, bunfig.toml, watch/hot modes, env vars, CLI flags, and module resolution.
Why this skill is useful
Provides specific commands and usage patterns for Bun runtime that the AI wouldn't reliably generate on its own.
What it needs
Requires bun installed locally. About 3k tokens when loaded. Last updated 2026-08-06. 204 stars on the source repository.
What this skill does
Bun Runtime Bun is a fast all-in-one JavaScript runtime built on JavaScriptCore (Safari's engine). It provides 4x faster startup than Node.js on Linux. Quick Start Core CLI Flags Flag Purpose ------ --------- --watch Restart on file changes --hot Hot module replacement (preserves state) --smol Reduce memory usage (slower GC) --inspect Enable debugger --preload Load modules before execution --env-file Load specific .env file -e, --eval Evaluate code string Running Files Bun transpiles TypeScript and JSX on-the-fly: Important: Put Bun flags immediately after bun: Package.json Scripts Bun respects lifecycle hooks (preclean, postclean, etc.). Watch Mode vs Hot Reloading Mode Flag Behavior ------ ------ ---------- Watch --watch Full process restart on changes Hot --hot Replace modules, preserve state Environment Variables Bun automatically loads .env files: Access in code: Globals Available Global Source Notes -------- -------- ------- Bun Bun Main API object Buffer Node.js Binary data process Node.js Process info fetch Web HTTP requests Request/Response Web HTTP types WebSocket Web WebSocket client crypto Web Cryptography console Web Logging dirname Node.js Current directory filename Node.js Current file Preload Scripts Load modules before your main script: Or in bunfig.toml: Use cases: polyfills, global setup, instrumentation. Stdin Execution Workspaces & Monorepos Debugging Connect via Chrome DevTools or VS Code. …
How to use it
Reference it in AdaL, Claude Code, Cursor or any coding agent — nothing to install:
@skills secondsky/bun-runtime