# X_WORKSPACE_EXTERNAL_DEP_UNDECLARED

## Means

a workspace imports a registry package that neither it nor the app root declares

## Typical cause

a workspace imports a package only a sibling workspace declares; it resolves through the hoisted node_modules until a clean or filtered install stops hoisting it

## Fix

`bun add <package> --cwd <workspace>` — the package-shape finding names both

[CLI and verify](/error-codes#cli-and-verify)