How do I install the Tsdown skill?

Run npx skillmds@latest add dobroslavradosavljevic/tsdown in your terminal (requires Node.js), paste this page's agent-chat prompt into Claude, Cursor, or any MCP-connected agent, or download the SKILL.md file and copy it into your agent's skills directory.

Is Tsdown safe to use?

This skill has not completed SkillMD's automated safety review yet. SkillMD never runs a skill's scripts for you; review the SKILL.md before installing.

Which AI agents work with Tsdown?

This skill is tagged as working with Claude Code, Claude.ai, OpenAI Codex. SKILL.md is an open format, so most agents that read a skills directory can load it too.

Is Tsdown free to use?

Yes. Installing skills from SkillMD is free, and the skill stays under its author's original license.

Who published Tsdown?

dobroslavradosavljevic (@dobroslavradosavljevic) published this skill. Their other Agent Skills are listed on their SkillMD profile.

Tsdown by dobroslavradosavljevic — Agent Skill

Name: Tsdown
Author: dobroslavradosavljevic

Tsdown

Build, review, debug, configure, migrate, teach, or plan tsdown library bundling with current docs and a full usage guide. Use for tsdown, tsdown.config, defineConfig, entry, format esm/cjs, dts, deps.neverBundle/alwaysBundle, exports, unbundle, watch, minify, target, platform, copy, CSS (@tsdown/css), plugins, workspace, programmatic build(), and tsup to tsdown migration.

File contents

tsdown

Use this skill when work touches tsdown: library builds, tsdown.config, dts/exports, dependency externalization, watch/unbundle, CSS/plugins/workspace, or migrating from tsup.

Workflow

Inspect the local tsdown surface:
- Package version (tsdown@0.22.x preferred; snapshot 0.22.14). Node to run the tool: ^22.18.0 || >=24.11.0.
- Config: tsdown.config.ts / package.json#tsdown; peers (typescript, @tsdown/css, publint, …).
- package.json type, exports, types, engines.node (feeds target/dts auto-detect).
- Whether migrating from tsup (external, entryPoints, bundle: false, …).
For day-to-day how-to, follow usage-guide.md first.
Refresh docs when versions drift (especially 0.23 beta). Start from source-map.md.
Route deeper detail:
- Config/CLI/defaults: config-cli.md.
- dts, package exports, deps: dts-exports-deps.md.
- Plugins, CSS, copy, workspace, programmatic: plugins-css-workspace.md.
- tsup migration: migrate-from-tsup.md.
Prefer current APIs: entry, deps.neverBundle / alwaysBundle, unbundle, copy, cjsDefault. Treat CJS as maintenance; prefer ESM-only for new libraries.
Verify with bunx tsdown (or project build), check dist + exports/types, then consume the package from a smoke import.

Core Judgment

tsdown = library bundler on Rolldown + Oxc — spiritual successor to tsup, not an app bundler.
Defaults differ from tsup: format: 'esm', clean: true, dts often auto from package.json types/exports, target from engines.node.
Prefer deps.neverBundle / alwaysBundle over deprecated external / noExternal.
Default dep policy: package dependencies/peers are externalized; used devDependencies may be bundled — override with deps when wrong.
Install typescript for dts (unless oxc fast path via isolatedDeclarations).
@tsdown/css / @tsdown/exe must match the tsdown version when used.
No stub mode — use --watch and/or exports.devExports.
Code splitting is always on — no splitting: false.
Pin skill guidance to 0.22.14 unless the project is on 0.23 beta; clear deprecations on 0.22 before jumping to 0.23.
Prefer bun / bunx in command examples.

Verification

Prefer repository-owned commands. For meaningful tsdown work, cover the relevant subset:

bunx tsdown --version and confirm Node engine for the CLI.
Clean build: bunx tsdown / bun run build; inspect dist formats and extensions (.mjs/.cjs/.js).
Types: consume .d.ts / exports.types from a dependent package or tsc.
Dual-format: require + import smoke when format includes both.
After exports: true: validate package.json with publint/attw if enabled.
Migration: zero deprecation warnings on 0.22 before upgrading to 0.23+.

Report which checks ran, which did not, and any version assumptions that remain.

---name: tsdowndescription: Build, review, debug, configure, migrate, teach, or plan tsdown library bundling with current docs and a full usage guide. Use for tsdown, tsdown.config, defineConfig, entry, format esm/cjs, dts, deps.neverBundle/alwaysBundle, exports, unbundle, watch, minify, target, platform, copy, CSS (@tsdown/css), plugins, workspace, programmatic build(), and tsup to tsdown migration.---# tsdownUse this skill when work touches tsdown: library builds, `tsdown.config`, dts/exports, dependency externalization, watch/unbundle, CSS/plugins/workspace, or migrating from tsup.## Workflow1. Inspect the local tsdown surface: - Package version (`tsdown@0.22.x` preferred; snapshot **0.22.14**). Node to **run** the tool: `^22.18.0 || >=24.11.0`. - Config: `tsdown.config.ts` / `package.json#tsdown`; peers (`typescript`, `@tsdown/css`, `publint`, …). - `package.json` `type`, `exports`, `types`, `engines.node` (feeds target/dts auto-detect). - Whether migrating from tsup (`external`, `entryPoints`, `bundle: false`, …).2. For day-to-day how-to, follow [usage-guide.md](references/usage-guide.md) first.3. Refresh docs when versions drift (especially **0.23 beta**). Start from [source-map.md](references/source-map.md).4. Route deeper detail: - Config/CLI/defaults: [config-cli.md](references/config-cli.md). - dts, package exports, deps: [dts-exports-deps.md](references/dts-exports-deps.md). - Plugins, CSS, copy, workspace, programmatic: [plugins-css-workspace.md](references/plugins-css-workspace.md). - tsup migration: [migrate-from-tsup.md](references/migrate-from-tsup.md).5. Prefer current APIs: `entry`, `deps.neverBundle` / `alwaysBundle`, `unbundle`, `copy`, `cjsDefault`. Treat CJS as maintenance; prefer ESM-only for new libraries.6. Verify with `bunx tsdown` (or project `build`), check `dist` + `exports`/types, then consume the package from a smoke import.## Core Judgment- tsdown = **library bundler** on **Rolldown + Oxc** — spiritual successor to tsup, not an app bundler.- Defaults differ from tsup: **`format: 'esm'`**, **`clean: true`**, dts often **auto** from `package.json` types/exports, target from **`engines.node`**.- Prefer **`deps.neverBundle` / `alwaysBundle`** over deprecated `external` / `noExternal`.- Default dep policy: package **dependencies/peers** are externalized; used **devDependencies** may be bundled — override with `deps` when wrong.- Install **`typescript`** for dts (unless oxc fast path via `isolatedDeclarations`).- `@tsdown/css` / `@tsdown/exe` must **match** the `tsdown` version when used.- No stub mode — use `--watch` and/or `exports.devExports`.- Code splitting is always on — no `splitting: false`.- Pin skill guidance to **0.22.14** unless the project is on 0.23 beta; clear deprecations on 0.22 before jumping to 0.23.- Prefer **`bun` / `bunx`** in command examples.## VerificationPrefer repository-owned commands. For meaningful tsdown work, cover the relevant subset:- `bunx tsdown --version` and confirm Node engine for the CLI.- Clean build: `bunx tsdown` / `bun run build`; inspect `dist` formats and extensions (`.mjs`/`.cjs`/`.js`).- Types: consume `.d.ts` / `exports.types` from a dependent package or `tsc`.- Dual-format: require + import smoke when `format` includes both.- After `exports: true`: validate `package.json` with publint/attw if enabled.- Migration: zero deprecation warnings on 0.22 before upgrading to 0.23+.Report which checks ran, which did not, and any version assumptions that remain.

Frequently asked questions