diff --git a/apps/web/src/lib/desktop-repository.test.mjs b/apps/web/src/lib/desktop-repository.test.mjs
new file mode 100644
index 00000000..4cab6520
--- /dev/null
+++ b/apps/web/src/lib/desktop-repository.test.mjs
@@ -0,0 +1,33 @@
+import { describe, expect, test } from "bun:test";
+
+let lastRequest = null;
+
+globalThis.window = {
+  location: { hostname: "notes.example.com", origin: "https://notes.example.com" },
+  edgeeverDesktop: {
+    isAvailable: true,
+    sidecarRequest: async (method, params) => {
+      lastRequest = { method, params };
+      return { memos: [], totalCount: 0, nextCursor: null };
+    },
+  },
+};
+
+const { createDesktopRepository } = await import("./desktop-repository.ts");
+
+describe("desktop repository notebook filters", () => {
+  test("uses the notebook subtree without also restricting results to the parent", async () => {
+    await createDesktopRepository().listMemos({
+      notebookId: "parent",
+      notebookIds: ["parent", "child"],
+    });
+
+    expect(lastRequest).toEqual({
+      method: "memo.list",
+      params: {
+        notebookId: null,
+        notebookIds: ["parent", "child"],
+      },
+    });
+  });
+});
diff --git a/apps/web/src/lib/desktop-repository.ts b/apps/web/src/lib/desktop-repository.ts
index ac91245d..95396c9e 100644
--- a/apps/web/src/lib/desktop-repository.ts
+++ b/apps/web/src/lib/desktop-repository.ts
@@ -195,7 +195,7 @@ export const createDesktopRepository = (): EdgeEverRepository => ({
   listMemos: (params) => {
     const rpcParams: DesktopMemoListParams = {
       ...params,
-      notebookId: params.notebookId ?? params.notebookIds?.[0] ?? null,
+      notebookId: params.notebookIds?.length ? null : (params.notebookId ?? null),
     };
     return request("memo.list", rpcParams);
   },
diff --git a/crates/desktop-sidecar/src/main.rs b/crates/desktop-sidecar/src/main.rs
index b3403e98..0c8b6ac3 100644
--- a/crates/desktop-sidecar/src/main.rs
+++ b/crates/desktop-sidecar/src/main.rs
@@ -809,12 +809,19 @@ fn list_memos(database: &Connection, params: &Value) -> Result<Value, String> {
         .unwrap_or("")
         .trim()
         .to_owned();
-    let notebook_id = params.get("notebookId").and_then(Value::as_str);
     let notebook_ids = params
         .get("notebookIds")
         .and_then(Value::as_array)
         .cloned()
         .unwrap_or_default();
+    // A notebookIds collection represents the complete notebook subtree and
+    // therefore supersedes the singular notebookId. Applying both filters
+    // would reduce the subtree back to the parent notebook alone.
+    let notebook_id = if notebook_ids.is_empty() {
+        params.get("notebookId").and_then(Value::as_str)
+    } else {
+        None
+    };
     let notebook_ids_json = Value::Array(notebook_ids).to_string();
     let filter = match params.get("filter").and_then(Value::as_str) {
         Some("pinned") => " AND m.is_pinned = 1",
diff --git a/package.json b/package.json
index 81df9a83..da271f9f 100644
--- a/package.json
+++ b/package.json
@@ -43,7 +43,7 @@
     "release": "bun scripts/release.mjs",
     "publish:stores": "bun scripts/store-delivery.mjs",
     "test:desktop:sidecar": "bun scripts/test-desktop-sidecar.mjs",
-    "test:desktop": "bun test apps/desktop/src/main/account-scope.test.mjs apps/desktop/src/main/diagnostic-log.test.mjs apps/desktop/src/main/file-association.test.mjs apps/desktop/src/main/file-permissions.test.mjs apps/desktop/src/main/installation-location.test.mjs apps/desktop/src/main/resource-request.test.mjs apps/desktop/src/main/resource-url.test.mjs apps/desktop/src/main/staged-resource.test.mjs apps/desktop/src/main/tray-icon.test.mjs apps/desktop/src/main/user-data-directory.test.mjs apps/desktop/src/main/window-open-policy.test.mjs apps/desktop/src/main/window-visibility.test.mjs apps/web/src/lib/api.test.mjs apps/web/src/lib/app-page-path.test.mjs apps/web/src/lib/desktop-resources.test.mjs apps/web/src/lib/desktop-sync.test.mjs apps/web/src/lib/local-mirror.test.mjs apps/web/src/lib/repository.test.mjs apps/web/src/lib/runtime.test.mjs apps/web/src/lib/sync-queue.test.mjs && bun run test:desktop:sidecar",
+    "test:desktop": "bun test apps/desktop/src/main/account-scope.test.mjs apps/desktop/src/main/diagnostic-log.test.mjs apps/desktop/src/main/file-association.test.mjs apps/desktop/src/main/file-permissions.test.mjs apps/desktop/src/main/installation-location.test.mjs apps/desktop/src/main/resource-request.test.mjs apps/desktop/src/main/resource-url.test.mjs apps/desktop/src/main/staged-resource.test.mjs apps/desktop/src/main/tray-icon.test.mjs apps/desktop/src/main/user-data-directory.test.mjs apps/desktop/src/main/window-open-policy.test.mjs apps/desktop/src/main/window-visibility.test.mjs apps/web/src/lib/api.test.mjs apps/web/src/lib/app-page-path.test.mjs apps/web/src/lib/desktop-repository.test.mjs apps/web/src/lib/desktop-resources.test.mjs apps/web/src/lib/desktop-sync.test.mjs apps/web/src/lib/local-mirror.test.mjs apps/web/src/lib/repository.test.mjs apps/web/src/lib/runtime.test.mjs apps/web/src/lib/sync-queue.test.mjs && bun run test:desktop:sidecar",
     "verify:desktop-package": "bun scripts/verify-desktop-package.mjs",
     "build:cloudflare": "bun run typecheck && bun run build",
     "build:site": "bun --cwd apps/site build",
diff --git a/scripts/test-desktop-sidecar.mjs b/scripts/test-desktop-sidecar.mjs
index 012ace27..ca993cbd 100644
--- a/scripts/test-desktop-sidecar.mjs
+++ b/scripts/test-desktop-sidecar.mjs
@@ -53,6 +53,15 @@ assert.equal((await request("memo.get", { memoId: first.memo.id })).memo.id, fir
 const second = await request("memo.create", { notebookId: inbox.id, title: "Second memo", contentMarkdown: "another body", tags: [] });
 const search = await request("memo.list", { q: "searchable", limit: 20 });
 assert.deepEqual(search.memos.map((memo) => memo.id), [first.memo.id]);
+const childNotebook = (await request("notebook.create", { name: "Inbox child", parentId: inbox.id })).notebook;
+const childMemo = await request("memo.create", { notebookId: childNotebook.id, title: "Nested memo", contentMarkdown: "nested body", tags: [] });
+const subtree = await request("memo.list", {
+  notebookId: inbox.id,
+  notebookIds: [inbox.id, childNotebook.id],
+  limit: 20,
+});
+assert.ok(subtree.memos.some((memo) => memo.id === first.memo.id), "parent notebook notes should remain in a subtree query");
+assert.ok(subtree.memos.some((memo) => memo.id === childMemo.memo.id), "subtree queries should include child notebook notes");
 await request("memo.update", {
   memoId: first.memo.id,
   title: "Local first updated",
@@ -195,4 +204,4 @@ assert.equal((await request("sync.status")).conflict, 0);
 
 child.stdin.end();
 await new Promise((resolve) => child.once("close", resolve));
-console.log(JSON.stringify({ ok: true, checked: ["memo.create", "memo.list.search", "memo.update", "memo.update.coalesce", "memo.revisions", "memo.restoreRevision", "memo.revision.cache", "tag.rename", "memo.moveBatch", "memo.pinBatch", "memo.deleteBatch", "memo.restore", "memo.emptyTrash", "memo.merge", "template.cache", "template.create.payload", "template.delete", "storage.backup", "storage.backups", "storage.restore", "sync.outbox", "sync.outbox.discard"] }));
+console.log(JSON.stringify({ ok: true, checked: ["memo.create", "memo.list.search", "memo.list.subtree", "memo.update", "memo.update.coalesce", "memo.revisions", "memo.restoreRevision", "memo.revision.cache", "tag.rename", "memo.moveBatch", "memo.pinBatch", "memo.deleteBatch", "memo.restore", "memo.emptyTrash", "memo.merge", "template.cache", "template.create.payload", "template.delete", "storage.backup", "storage.backups", "storage.restore", "sync.outbox", "sync.outbox.discard"] }));