[Bug] peerDependencies admit storybook 9.1.x, where the preset fails to load and the components manifest does not exist in core

[rachelslurs]

What happened

I added @storybook/addon-mcp@0.7.0 to a clone of radix-ui/primitives (commit df8f89ac, apps/storybook, storybook 9.1.20). The install succeeded: the published peer range ^0.0.0-0 || ^9.1.16 || ^10.0.0 || ^10.1.0-0 || ^10.2.0-0 || ^10.3.0-0 || ^10.4.0-0 || ^10.5.0-0 admits 9.1.20. storybook build then failed while loading presets:

Error [ERR_INTERNAL_ASSERTION]: Unexpected module status 0

That error masks the cause. Importing the preset directly exposes it:

SyntaxError: The requested module 'storybook/internal/common' does not provide an export named 'importModule'

dist/preset.js imports importModule from storybook/internal/common, and storybook 9.1.20 does not export it. importModule appears nowhere in 9.1.20's dist/common/index.js or index.cjs, while the preset's other import from the same module, normalizeStoryPath, is present.

Fixing the import would not be enough on 9.1.x

The manifest feature is absent from storybook core on the 9.1 line under both of its flag spellings. Grep counts over the published storybook dist tarballs, occurrences anywhere in dist:

storybook	componentsManifest	experimentalComponentsManifest	importModule in dist/common
9.1.17	0	0	0
9.1.20	0	0	0
10.0.0, 10.0.8	0	0	2
10.1.0, 10.1.10, 10.1.11	0	3	2
10.2.0, 10.2.10, 10.2.14, 10.2.19	0	3	2
10.3.0	7	0	2

The feature enters core at 10.1.0 under the experimental spelling, and the stable spelling replaces it at 10.3.0. On 9.1.x neither spelling exists, so the ^9.1.16 floor admits a version line where the preset cannot load and, with the import fixed, would find no manifest feature to use. Builds confirm the table at three points: the preset fails to load at 9.1.20, and storybook build writes storybook-static/manifests/components.json with the addon alone at 10.3.5 and 10.4.2, and with the addon plus features: { componentsManifest: true } at 10.5.3. I have not tested whether the addon produces a manifest on the 10.1 to 10.2 band with the experimental flag.

Reproduction

1. git clone https://github.com/radix-ui/primitives and check out df8f89ac
2. pnpm install
3. pnpm --dir apps/storybook add -D @storybook/addon-mcp@0.7.0
4. Add '@storybook/addon-mcp' to the addons array in apps/storybook/.storybook/main.ts
5. pnpm --dir apps/storybook run build

Fails during preset loading. Reproduced on Node 22.20.0 and Node 24.14.0 (the repo's .nvmrc pins 24), macOS, pnpm 11.5.0.

Expected

Either the peer floor matches a version line the addon works on (10.3.x through 10.5.x is demonstrated; 10.1 to 10.2 carries only the experimental flag and is untested), or the preset fails on 9.1.x with a message naming the minimum version. Every published version from 0.1.4 through 0.7.0, prereleases included, carries the ^9.1.16 floor, and 0.0.9 was looser still at >=9.0.0, so pinning an older addon does not avoid this.

[rachelslurs]

I wrote above that I had not tested whether the addon produces a manifest on 10.1 to 10.2. Tested now: three builds on palantir/blueprint, storybook 10.2.14 exact pins, all exit 0, config as the only variable.

config	manifest emitted
features: { experimentalComponentsManifest: true }, addon not registered	yes (55 components)
addon registered, no features key	no
addon registered plus the flag	yes, identical component set to flag-only

On 10.2.14 the experimental core flag produces the static manifest. The addon contributes nothing to emission there.

The 10.2.14 manifest also has no meta block. 10.3.x manifests name their extractor in meta.docgen; this format names none.

One more result from the same run, on the rename side: a stale experimentalComponentsManifest: true on storybook 10.3.5 builds green with zero warnings mentioning the key. Nothing in 10.3.0 core reads the old name (zero occurrences, type declarations included). The manifest still appears with the addon installed, which produces manifests on its own at 10.3.5.

Where this leaves the range: the addon's demonstrated working range is 10.3.x through 10.5.x. On 10.1 to 10.2, manifests exist only via the experimental core flag, with no addon involvement. On 9.1.x nothing can produce one. The published floor of ^9.1.16 matches none of those boundaries.