diff --git a/src/documents/resolveDocumentLink.ts b/src/documents/resolveDocumentLink.ts
index 615aa72..ab4fb27 100644
--- a/src/documents/resolveDocumentLink.ts
+++ b/src/documents/resolveDocumentLink.ts
@@ -5,7 +5,15 @@ import type { OpenDocRequest } from '../workspaces/workspace';
 export type LinkSource = {
   /** Provider the current document belongs to. */
   providerId: string;
-  /** The current document's id/path (links resolve relative to its folder). */
+  /**
+   * The current document's filesystem path; links resolve relative to its
+   * folder.
+   *
+   * Must come from `OpenDocRequest.entryId`, NOT from `DocumentHandle.id`.
+   * They coincide for a local vault, but a synced vault's handle id is an
+   * `at://` URI (`syncedVaultDocumentsProvider` sets `id: session.uri`), and
+   * taking `dirname` of that yields a target no provider can open.
+   */
   path: string;
 };
 
diff --git a/src/editors/DocumentSlotView.tsx b/src/editors/DocumentSlotView.tsx
index a09c007..df4509e 100644
--- a/src/editors/DocumentSlotView.tsx
+++ b/src/editors/DocumentSlotView.tsx
@@ -57,12 +57,16 @@ export function DocumentSlotView({
   // Resolve internal-link targets against this document, then route to the
   // workspace's open handler. Kept here (not in each workspace) so every
   // workspace gets file-to-file navigation for free.
+  // Resolve from `request.entryId`, NOT `handle.id`: the handle's id is the
+  // provider's own document identity, which for a synced vault is an `at://`
+  // URI rather than a path (`syncedVaultDocumentsProvider` sets `id:
+  // session.uri`). `entryId` is always the absolute path in both providers.
   const { request, handle } = state;
   const onOpenLink = onOpenEntry
     ? (target: string) =>
         onOpenEntry(
           resolveDocumentLink(
-            { providerId: request.providerId, path: handle.id },
+            { providerId: request.providerId, path: request.entryId },
             target,
           ),
         )