Summary
This is a comprehensive reference guide for migrating TypeScript library projects from tsup to tsdown, the newer Rolldown-powered bundler. It covers the full migration path: renaming config files, transforming options like cjsInterop to cjsDefault, moving external and noExternal into a deps namespace, and handling the different defaults (tsdown defaults to ESM and auto-enables DTS). The guide includes explicit mappings for deprecated options, alternatives for unsupported features like splitting and metafile, and package.json updates. Use this when you need to port a tsup build setup to tsdown or troubleshoot compatibility issues. The detail level is thorough enough that an agent can execute the migration without guessing.
Install to Claude Code
npx -y skills add rolldown/tsdown --skill tsdown-migrate --agent claude-codeInstalls into .claude/skills of the current project.
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Files
SKILL.md
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Featured
Keep your Mac awake while Claude Code and 40+ AI agents run. Sleeps when they're idle.
One time payment $9 →Integrate web data into your AI product. One API to scrape website & brand data.
Get API Key Now →Agent, run crypto. Access onchain data & trade routes via 1inch.
Install now →On Capafy, your Skill runs online 24/7 as an agent product, and you get paid every time someone uses it.
Start earning →First SeenJun 3, 2026
