[Sandbye]

AI usage

• No AI was used in this PR.
• AI was used: Codex (gpt-5.6-luna High)
  • I have carefully reviewed the AI-generated content myself.

Description

Attempt at adding a generated JSON Schema for tsdown.config.json.

Generation
The schema was generated from tsdown’s UserConfig TypeScript type using the TypeScript compiler API.

It preserves:

• Property descriptions from JSDoc
• @default values when they are JSON-compatible literals
• @deprecated annotations
• Reusable $defs and $ref definitions

Function-only options, plugins, and callbacks are omitted because they cannot be represented in JSON.

The generator is currently kept separate from this PR. If preferred, it can be added to the repository later to regenerate the schema automatically.

Linked Issues

fix #679

Additional context

Verified with:

• pnpm lint
• pnpm typecheck
• pnpm test run

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[pkg-pr-new]

Open in StackBlitz

tsdown

pnpm add https://pkg.pr.new/rolldown/tsdown@1074 -D

npm i https://pkg.pr.new/rolldown/tsdown@1074 -D

yarn add https://pkg.pr.new/rolldown/tsdown@1074.tgz -D

create-tsdown

pnpm add https://pkg.pr.new/rolldown/tsdown/create-tsdown@1074 -D

npm i https://pkg.pr.new/rolldown/tsdown/create-tsdown@1074 -D

yarn add https://pkg.pr.new/rolldown/tsdown/create-tsdown@1074.tgz -D

@tsdown/css

pnpm add https://pkg.pr.new/rolldown/tsdown/@tsdown/css@1074 -D

npm i https://pkg.pr.new/rolldown/tsdown/@tsdown/css@1074 -D

yarn add https://pkg.pr.new/rolldown/tsdown/@tsdown/css@1074.tgz -D

@tsdown/exe

pnpm add https://pkg.pr.new/rolldown/tsdown/@tsdown/exe@1074 -D

npm i https://pkg.pr.new/rolldown/tsdown/@tsdown/exe@1074 -D

yarn add https://pkg.pr.new/rolldown/tsdown/@tsdown/exe@1074.tgz -D

tsdown-migrate

pnpm add https://pkg.pr.new/rolldown/tsdown/tsdown-migrate@1074 -D

npm i https://pkg.pr.new/rolldown/tsdown/tsdown-migrate@1074 -D

yarn add https://pkg.pr.new/rolldown/tsdown/tsdown-migrate@1074.tgz -D

commit: a5aec1c

[sxzz]

The JSON Schema is too large to maintain manually, so we need automated tooling to keep it up to date. Please include the generator in this PR; without it, ongoing maintenance would not be feasible.

The schema file is also quite large and would increase the npm package size. I'd prefer to keep it in the GitHub repository and let users load it via a URL, rather than include it in the published npm package.

[Sandbye]

Yeah, i totally agree. Will follow up on that.

[sxzz]

Actually, I'd prefer to have the generator produce a Zod (or Zod-like) schema first, then convert it to JSON Schema. This would make the code more intuitive to maintain and the process more reliable.

[sxzz]

Since Rolldown uses Valibot, I'd actually prefer Valibot over Zod here.

[Sandbye]

Agreed. I’ll rework the generator to produce Valibot schemas first and convert those to JSON Schema, then include the generator and generated schema in the PR. I’ll also keep the generated schema out of the npm package and serve it from the repository instead. :)

[socket-security]

Review the following changes in direct dependencies. Learn more about Socket for GitHub.

Diff	Package	Supply Chain Security	Vulnerability	Quality	Maintenance	License
	@​valibot/​to-json-schema@​1.8.0

View full report

[sxzz]

Also run schema:generate script in autofix.yml.

[Sandbye]

Question
I found that function/API-only types are not limited to the root-level hooks and customLogger options. Nested options such as format-specific hooks/loggers, minify.mangleProps, and visitor APIs also become empty schemas ({}).

Should the JSON-specific schema omit all function/API-only options recursively, or should these remain unconstrained?

[sxzz]

I'd prefer to keep these options unconstrained in the JSON Schema, including nested ones, rather than omit them.

[Sandbye]

I'd prefer to keep these options unconstrained in the JSON Schema, including nested ones, rather than omit them.

Cool, then this PR is ready for final review. Nothing else from me.

[silashoeyer]

looks good to me

[sxzz]

LGTM. Maybe we can also introduce a new package @tsdown/schema, providing valibot & JSON schema to AI agents.

[Sandbye]

LGTM. Maybe we can also introduce a new package @tsdown/schema, providing valibot & JSON schema to AI agents.

Great! Should @tsdown/schema be a follow-up issue, or would you rather have it included in this pr?

[sxzz]

I'm okay for both. It's up to you. BTW, I'm currently on vacation, and this PR will be delayed by few days.

[Sandbye]

Have a nice vacation 🌴
I'll look into it when i have time next week.

[Sandbye]

@sxzz
I’ll leave @tsdown/schema as a follow-up so this PR stays focused on adding the JSON Schema and generator. Thanks for the suggestion!