Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Inline comments:
In `@packages/kit/src/diagnostics/_shared.ts`:
- Around line 11-12: The docs URL in docsBase is being exposed as a raw
interpolated template literal, which Lychee interprets as a literal URL and
trips over the placeholder. Refactor docsBase in _shared.ts to construct the
path from a separate base constant or with new URL() plus string concatenation,
so the source no longer contains the full interpolated URL verbatim while still
returning the same final docs link.
- Around line 16-21: The exported `reporters` constant in `_shared.ts` relies on
an inferred tuple type, which can interfere with declaration generation in
`tsdown` with `dts: { oxc: true }`. Add an explicit type annotation for
`reporters` so the exported shape is stable and declaration emit can succeed.
Use the existing `reporters` export and the
`createConsoleReporter`/`ansiFormatter` expression as the location to update,
without changing runtime behavior.

In `@packages/kit/src/diagnostics/components.ts`:
- Line 5: Add an explicit type annotation to the exported diagnostics object so
declaration emit under isolatedDeclarations does not rely on inference. Update
componentDiagnostics to declare its type at the export, and apply the same fix
to the other defineDiagnostics(...) exports in packages/kit/src/diagnostics/*.ts
so all exported diagnostics objects have explicit types.

In `@packages/kit/src/diagnostics/config.ts`:
- Line 5: The `configDiagnostics` export in `defineDiagnostics` is missing an
explicit exported type, which triggers declaration-generation issues under
isolated declarations. Update the `configDiagnostics` definition to use a named,
exported type annotation so TypeScript can emit declarations cleanly for
`@nuxt/kit`, and keep the symbol name `configDiagnostics` unchanged so existing
imports continue to work.

In `@packages/kit/src/diagnostics/head.ts`:
- Line 5: The exported diagnostics catalogue in headDiagnostics needs an
explicit declared type so declaration emit can succeed. Update the export at
headDiagnostics to include a concrete type annotation using the appropriate
diagnostics catalogue type from defineDiagnostics, keeping the existing
initialization logic intact. Use the headDiagnostics symbol and the
defineDiagnostics call to locate the export and add the annotation without
changing its runtime behavior.

In `@packages/kit/src/module/install.ts`:
- Around line 347-351: The module-missing check in install.ts is using a broad
includes() match, which can incorrectly treat sibling packages with the same
prefix as the requested module and raise NUXT_B8018 for the wrong failure.
Update the logic around MissingModuleMatcher and kitDiagnostics.NUXT_B8018 to
compare the extracted module against nuxtModule exactly, or only accept direct
subpath variants of the requested specifier. Keep the existing subdependency
guard, but make the requested-module detection precise so only the intended
module name triggers this diagnostic.

In `@packages/nuxt/src/app/components/nuxt-island.ts`:
- Around line 239-241: The diagnostic detail in nuxt-island’s catch block is too
narrow because it reads e.message from an any, which becomes undefined for
string or plain-object throwables. Update the error normalization in the
NUXT_E4012 path so the detail is derived from the thrown value itself (like the
previous toString() behavior) before calling renderDiagnostics.NUXT_E4012,
keeping the existing status/name/cause handling intact.

In `@packages/nuxt/src/app/composables/once.ts`:
- Around line 25-29: The callback validation in callOnce should remain
unconditional, because fn is required and allowing undefined makes
callOnce('key') fail later with a raw runtime error instead of NUXT_E7008.
Update the guard in once.ts so the NUXT_E7008 check still rejects any
non-function value, including undefined, before execution reaches the later call
site in callOnce.

In `@packages/nuxt/src/app/composables/router.ts`:
- Around line 182-186: The `navigateTo` open-path still throws a plain `Error`
before reaching the new diagnostics, so the script-protocol case is not using
the stable contract. Update the `navigateTo` logic in `router.ts` so the earlier
`options.open` guard uses the same `NUXT_E2002` diagnostic as the `toPath` URL
check, and make sure the check reports the resolved protocol consistently for
both paths.

In `@packages/nuxt/src/app/diagnostics/_shared.ts`:
- Around line 17-18: The docsBase helper is embedding an unresolved template
literal URL, which the link-checker treats as a real link. Update docsBase to
build the docs URL from a base constant or via new URL() instead of
interpolating the path directly, and keep the code.replace('NUXT_',
'').toLowerCase() logic intact while moving the URL construction into a
non-literal form.

In `@packages/nuxt/src/app/diagnostics/navigation.ts`:
- Around line 15-18: The `NUXT_E2002` diagnostic fix text is too narrow because
`isScriptProtocol(protocol)` only blocks script-like schemes, not all non-http
URLs. Update the `fix` message in the `NUXT_E2002` entry to explain that
`javascript:`-style protocols are blocked for security, while safe schemes like
`mailto:` and `tel:` remain valid, and direct users to use a safe URL/protocol
appropriate for the link target.

In `@packages/nuxt/src/app/diagnostics/render.ts`:
- Around line 66-68: Update the NUXT_E4012 guidance in the diagnostics mapping
so it matches the actual failure path in nuxt-island.ts: the parse error comes
from r.json(), not HTML parsing. Keep the why message in render.ts as-is, but
change the fix text to instruct users to verify the island endpoint returns
valid JSON/island payload, and mention it may have returned an HTML error page
instead.

In `@packages/nuxt/src/app/diagnostics/state.ts`:
- Around line 36-39: The NUXT_E7006 diagnostic currently exposes sensitive
cookie values in its why message; update the diagnostic in state.ts so the
NUXT_E7006 entry only mentions the cookie name or uses redacted placeholders
instead of p.previous and p.next. Keep the fix in the NUXT_E7006 catalog entry
and adjust the why function signature or formatting in that diagnostic so SSR
logs never contain raw cookie contents.

In `@packages/nuxt/src/components/scan.ts`:
- Around line 101-102: The `scan.ts` diagnostics for `NUXT_B3009` and
`NUXT_B3011` are still using raw filesystem paths, unlike the other component
warnings in this file. Update the `componentDiagnostics.NUXT_B3009` and
`componentDiagnostics.NUXT_B3011` calls in `scanComponents` to pass the path
through `resolveToAlias(...)` first, matching the existing usage near the other
diagnostics so `filePath` is consistent across machines.

In `@packages/nuxt/src/core/app.ts`:
- Around line 68-70: The `compileTemplate()` rejection handler in `app.ts` is
wrapping every failure in `NUXT_B1001`, which overrides the more specific
`NUXT_B1002`/`NUXT_B1003` diagnostics. Update the
`compileTemplate(...).catch(...)` logic so `NUXT_B1001` is only emitted for
unexpected exceptions, and let already-coded template failures pass through with
their original diagnostic. Apply the same change in the other `compileTemplate`
call site referenced by the comment.

In `@packages/nuxt/src/pages/runtime/plugins/router.ts`:
- Around line 250-252: The NUXT_E2004 navigation diagnostic in the router
middleware path is missing the registered named middleware context, so the dev
error no longer shows which middleware names are available. Update the call site
in the router plugin to pass the current named middleware set into
navigationDiagnostics.NUXT_E2004, or preserve the existing dev-only suffix that
includes that list, using the surrounding middleware handling logic and the
NUXT_E2004 symbol to locate the fix.

In `@packages/vite/src/plugins/optimize-deps-hint.ts`:
- Around line 126-128: The stale-deps hint branch in optimize-deps-hint should
preserve the stale dependency names instead of emitting an empty NUXT_B7002
payload. Update the hasStale path in the logic around formatStaleDepsHint so it
still passes the userStale/moduleStale information (or equivalent stale dep
names) into bundlerDiagnostics.NUXT_B7002, keeping the warning actionable when
no new deps are discovered.

---

Outside diff comments:
In `@packages/nuxt/src/components/plugins/lazy-hydration-transform.ts`:
- Around line 95-105: Normalize the file path used by NUXT_B3005 in
lazy-hydration-transform so it matches the aliased path format already used for
NUXT_B3006. Update the componentDiagnostics.NUXT_B3005 call to pass
resolveToAlias(id, nuxt) (or an equivalent shared normalized value) instead of
the raw id, so both diagnostics report consistent, environment-independent file
references.

In `@packages/nuxt/src/pages/plugins/page-meta.ts`:
- Around line 103-112: Restore the hard failure path in page-meta handling: in
the empty-module branch inside the page transform logic, after
`pageDiagnostics.NUXT_B4001` is emitted, throw again instead of returning
`result()`. Update the `page-meta.ts` flow around `hasMacro`, `parseModuleId`,
and `pageDiagnostics.NUXT_B4001` so empty `?macro=true` modules still stop the
build rather than continuing with the fallback transform output.

---

Nitpick comments:
In `@packages/nuxt/src/app/composables/asyncData.ts`:
- Around line 400-420: The NUXT_E3004 diagnostic currently omits the async-data
function name, making duplicate-options warnings harder to trace. In
asyncData.ts, pass the dev-only _functionName through to
dataDiagnostics.NUXT_E3004 alongside key and warnings, and update the NUXT_E3004
template in diagnostics/data.ts to include that fn field in the emitted message.

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Inline comments:
In `@packages/nuxt/src/app/composables/asyncData.ts`:
- Around line 359-362: The validation guards in asyncData should preserve the
existing TypeError contract instead of switching to Error-based diagnostics.
Update the checks in useAsyncData so the _key and _handler failures still throw
TypeError while keeping the same diagnostic messages, and make sure the existing
NUXT_E3008 and NUXT_E3009 paths continue to satisfy instanceof TypeError
expectations.