CSF Next still needs meta to be exported from stories

[kg-and-digital]

After upgrading to Storybook 10 and migrating from the webpack to vite builder. Decided to also migrate to CSF Next, and noticed that now you no longer need to include export default meta in the .stories files. This works fine in storybook dev mode, now when you do a storybook build the MDX files throw an error, which is fixed once you put back in the default export meta.

Not sure if this is a bug or incorrect documentation.

[dosubot[bot]]

Hi @kg-and-digital! I'm Dosu and I’m helping the storybook team.

This is a confirmed bug tracked in #34159 and #34373. CSF4 (preview.meta()) is designed so that export default meta should not be required, but production builds (storybook build) fail when MDX docs reference the story module via <Meta of={} /> without it.

Root cause: In production builds, the bundler can split story modules into separate chunks, causing object identity mismatches in DocsContext.resolveModuleExport(). Without a default export, the existing fallback can't reconcile the two different namespace objects [1].

This is specifically a Vite/Rolldown bundling issue in production builds — dev mode works fine because modules aren't chunked the same way [2].

Workaround: Keep export default meta in your story files for now:

const meta = preview.meta({ component: MyComponent });
export default meta;

If you're using Vite 8 specifically, downgrading to Vite 7 was confirmed to fix the issue as well [2]. The fix is being tracked upstream as part of Rolldown/Vite 8 support (#33063).

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