Field value retrieved from `form()` is initially empty

Update: Seems to apply to all form fields.

<script lang="ts">
  import { addId } from './ids.remote';

  console.log(addId.fields.checkbox.value());
  console.log(addId.fields.checkbox.set(true));
</script>

<input {...addId.fields.checkbox.as('checkbox')} />

Logs on both the server and the client:

undefined
true

Describe the bug

Despite windows being visually selected in the <select>, the os.value() starts of as an empty string.

<script lang="ts">
  import { FormSchema, osArray } from './ids';
  import { addId } from './ids.remote';
</script>

<form {...addId.preflight(FormSchema)} oninput={() => addId.validate()}>
  <label>
    <span>Operating System</span>
    <select {...addId.fields.os.as('select')}>
      <!-- eslint-disable-next-line svelte/require-each-key -->
      {#each osArray as os}
        <option>{os}</option>
      {/each}
    </select>
  </label>
  <p>{addId.fields.os.value()}</p>
</form>

// ids.remote.ts
import { form } from '$app/server';
import { FormSchema } from './ids';
export const addId = form(FormSchema, () => {});

// ids.ts
import { object, picklist } from 'valibot';
export const osArray = ['windows', 'mac', 'linux'] as const;
export const FormSchema = object({ os: picklist(osArray) });

It is updated only when the user switches the value.

Explicitly selecting the 1st item does not fix the issue.

{#each osArray as os, index}
  <option selected={!index}>{os}</option>
{/each}

Reproduction

• https://github.com/hyunbinseo/svelte-kit-template/tree/mre-kit-14676

Logs

System Info

System:
  OS: Windows 11 10.0.26100
  CPU: (8) x64 Intel(R) Core(TM) Ultra 7 258V
  Memory: 4.75 GB / 31.48 GB
Binaries:
  Node: 24.10.0 - C:\Users\hyunb\AppData\Local\fnm_multishells\14572_1760058974054\node.EXE
  Yarn: 1.22.22 - C:\Users\hyunb\AppData\Local\fnm_multishells\14572_1760058974054\yarn.CMD
  npm: 11.6.1 - C:\Users\hyunb\AppData\Local\fnm_multishells\14572_1760058974054\npm.CMD
  pnpm: 10.18.1 - C:\Users\hyunb\AppData\Local\fnm_multishells\14572_1760058974054\pnpm.CMD
  Deno: 2.4.0 - C:\Users\hyunb\.deno\bin\deno.EXE
Browsers:
  Chrome: 141.0.7390.66
  Edge: Chromium (140.0.3485.54)
  Firefox: 143.0.4 - C:\Program Files\Mozilla Firefox\firefox.exe
npmPackages:
  @sveltejs/adapter-auto: ^6.1.1 => 6.1.1
  @sveltejs/kit: ^2.46.4 => 2.46.4
  @sveltejs/vite-plugin-svelte: ^6.2.1 => 6.2.1
  svelte: ^5.39.11 => 5.39.11
  vite: ^7.1.7 => 7.1.7

Severity

annoyance

Additional Information

Related https://github.com/sveltejs/kit/issues/14667

Start with the linked reproduction and compare the Svelte form markup with ids.remote.ts and ids.ts. Trace the initial state of addId.fields values on both server and client, then verify that select and checkbox fields expose their initial values before user interaction. Done means the reported initial-value cases work without requiring a change event.