SvelteKit doesn't work without hooks file, can't turn off

[james-pre]

Describe the bug

I'm trying to use SvelteKit alongside another library. For that library, I have an src/hooks.ts file used to hook into that other library's lifecycle.

I'm not using SvelteKit's hooks, and yet when I try to build my project SvelteKit imports src/hooks.ts even though it isn't meant for SvelteKit. By making it so SvelteKit can't read it using a quick chmod 000, It looks to be imported by .svelte-kit/generated/server/internal.js.

I think the workaround for this bug says a lot about how not-magical it feels:

export default {
	kit: {
		adapter: node(),
		files: {
			hooks: {
				universal: '/dev/null',
			},
		},
	},
};

SvelteKit doesn't provide any way to say "Hey, I DO NOT want to use hooks in this project", meaning we have to resort to ridiculous workarounds. Futhermore, SvelteKit's planned removal of kit.files.* will result in no way to use SvelteKit alongside other libraries since SvelteKit expects (and in the future will require) an unreasonable invariant.

Reproduction

StackBlitz

At a high level:

• Create a file for another unrelated library, src/hooks.ts
• import a named export from node:fs and call it
• Try to build using npx vite build
• Error

Logs

$ npx vite build
The `config.kit.files.assets` option is deprecated, and will be removed in a future version
The `config.kit.files.appTemplate` option is deprecated, and will be removed in a future version
Your tsconfig.json should extend the configuration generated by SvelteKit:
{
  "extends": "./.svelte-kit/tsconfig.json"
}
vite v7.1.10 building SSR bundle for production...
✓ 182 modules transformed.
The `config.kit.files.assets` option is deprecated, and will be removed in a future version
The `config.kit.files.appTemplate` option is deprecated, and will be removed in a future version
The `config.kit.files.assets` option is deprecated, and will be removed in a future version
The `config.kit.files.appTemplate` option is deprecated, and will be removed in a future version
vite v7.1.10 building for production...
[plugin vite:resolve] Module "node:fs" has been externalized for browser compatibility, imported by "REDACTED/src/hooks.ts". See https://vite.dev/guide/troubleshooting.html#module-externalized-for-browser-compatibility for more details.
[plugin vite:resolve] Module "node:fs" has been externalized for browser compatibility, imported by "REDACTED/src/hooks.ts". See https://vite.dev/guide/troubleshooting.html#module-externalized-for-browser-compatibility for more details. (x2)
✓ 478 modules transformed.
✗ Build failed in 283ms
✗ Build failed in 788ms
error during build:
[vite-plugin-sveltekit-compile] src/hooks.ts (1:9): "writeFileSync" is not exported by "__vite-browser-external", imported by "src/hooks.ts".
file: REDACTED/src/hooks.ts:1:9

1: import { writeFileSync } from 'node:fs';
            ^

    at getRollupError (file://REDACTED/node_modules/rollup/dist/es/shared/parseAst.js:401:41)
    at error (file://REDACTED/node_modules/rollup/dist/es/shared/parseAst.js:397:42)
    at Module.error (file://REDACTED/node_modules/rollup/dist/es/shared/node-entry.js:16939:16)
    at Module.traceVariable (file://REDACTED/node_modules/rollup/dist/es/shared/node-entry.js:17391:29)
    at ModuleScope.findVariable (file://REDACTED/node_modules/rollup/dist/es/shared/node-entry.js:15061:39)
    at Identifier.bind (file://REDACTED/node_modules/rollup/dist/es/shared/node-entry.js:5413:40)
    at CallExpression.bind (file://REDACTED/node_modules/rollup/dist/es/shared/node-entry.js:2804:23)
    at CallExpression.bind (file://REDACTED/node_modules/rollup/dist/es/shared/node-entry.js:12108:15)
    at ExpressionStatement.bind (file://REDACTED/node_modules/rollup/dist/es/shared/node-entry.js:2804:23)
    at Program.bind (file://REDACTED/node_modules/rollup/dist/es/shared/node-entry.js:2800:28)

System Info

$ npx envinfo --system --binaries --browsers --npmPackages "{svelte,@sveltejs/*,vite}"
Need to install the following packages:
envinfo@7.19.0
Ok to proceed? (y) n

npm error canceled
npm error A complete log of this run can be found in: REDACTED.log

Severity

blocking all usage of SvelteKit

Additional Information

Dependencies: svelte v5.40.2, @sveltejs/kit v2.47.1, @sveltejs/adapter-node v5.4.0
Kernel: Linux
Node v24.9.0

More detailed system and app information is not relevant.

[teemingc]

We could probably make it a bit more obvious from the build logs that it's a reserved file name.

[james-pre]

Hey @teemingc,

While I think clear docs would be helpful, it wouldn't fix the root issue. SvelteKit is doing something that can't be turned off without an obviously unintended workaround. Having a special naming convention (e.g. +page.*) makes sense, but reserving a file name and making it non-configurable just doesn't seem right. Having a way to turn off this invasive behavior is a must.

[sacrosanctic]

seems like an easy fix, rename src/hooks.ts to src/library-hooks.ts.