diff --git a/apps/web/src/components/CommandPalette.browser.test.tsx b/apps/web/src/components/CommandPalette.browser.test.tsx
index 8292121ac2ce..7a9de4ca746c 100644
--- a/apps/web/src/components/CommandPalette.browser.test.tsx
+++ b/apps/web/src/components/CommandPalette.browser.test.tsx
@@ -1,3 +1,4 @@
+import { threadKey } from "@t3tools/client-runtime/state/entities";
 import { EnvironmentId, ProjectId, ThreadId } from "@t3tools/contracts";
 import { describe, expect, it, vi } from "vite-plus/test";
 import { page, userEvent } from "vite-plus/test/browser";
@@ -14,20 +15,23 @@ import { CommandPalette } from "./CommandPalette";
 const entities = vi.hoisted(() => ({
   projects: [] as ReadonlyArray<Project>,
   threads: [] as ReadonlyArray<Thread>,
+  delegatedUnderParent: new Set<string>() as ReadonlySet<string>,
 }));
 vi.mock("../state/entities", async (original) => ({
   ...(await original<typeof import("../state/entities")>()),
   useProjects: () => entities.projects,
   useVisibleThreadShells: () => entities.threads,
+  useDelegatedUnderParent: () => entities.delegatedUnderParent,
 }));
 
-function setup(state: { projects?: ReadonlyArray<Project>; threads?: ReadonlyArray<Thread> } = {}) {
+function setup(state: Partial<typeof entities> = {}) {
   // Earlier browser test files share this origin's localStorage; a remembered project
   // that is not listed here hides the default "New thread in <project>" row.
   removeLocalStorageItem(LAST_USED_PROJECT_STORAGE_KEY);
   useCommandPaletteStore.setState(useCommandPaletteStore.getInitialState(), true);
   entities.projects = state.projects ?? [];
   entities.threads = state.threads ?? [];
+  entities.delegatedUnderParent = state.delegatedUnderParent ?? new Set();
 }
 
 describe("CommandPalette open intents", () => {
@@ -134,11 +138,13 @@ describe("CommandPalette open intents", () => {
     await expect.element(input).toHaveValue("acme");
   });
 
-  it("opens a searched project's latest listed thread, not a newer subagent", async () => {
+  it("opens a searched project's latest listed thread, not a newer subagent or delegated task", async () => {
     const environmentId = EnvironmentId.make("local");
     const projectId = ProjectId.make("acme");
     const parentId = ThreadId.make("parent");
+    const delegatedId = ThreadId.make("delegated");
     setup({
+      delegatedUnderParent: new Set([threadKey({ environmentId, threadId: delegatedId })]),
       projects: [
         {
           id: projectId,
@@ -170,6 +176,12 @@ describe("CommandPalette open intents", () => {
             relationshipToParent: "subagent",
           },
         }),
+        makeThreadFixture({
+          id: delegatedId,
+          environmentId,
+          projectId,
+          latestUserMessageAt: "2026-03-04T00:00:00.000Z",
+        }),
       ],
     });
     await using screen = await render(<CommandPalette>{null}</CommandPalette>);
diff --git a/apps/web/src/components/CommandPalette.tsx b/apps/web/src/components/CommandPalette.tsx
index b0b8e510de5b..0ea2cd7a2015 100644
--- a/apps/web/src/components/CommandPalette.tsx
+++ b/apps/web/src/components/CommandPalette.tsx
@@ -138,6 +138,7 @@ import {
 } from "../state/environments";
 import {
   useAnyEnvironmentHiding,
+  useDelegatedUnderParent,
   useHiddenThreadKeys,
   useEnvironmentThreadRefs,
   useProjects,
@@ -145,7 +146,7 @@ import {
   useVisibleThreadShells,
   waitForProject,
 } from "../state/entities";
-import { visibleLinkedThreads } from "@t3tools/client-runtime/state/threads";
+import { isShownUnderParent, visibleLinkedThreads } from "@t3tools/client-runtime/state/threads";
 import {
   resolveThreadActionProjectRef,
   startNewThreadFromContext,
@@ -229,7 +230,6 @@ import {
   type SearchOverlayMode,
 } from "./CommandPalette.logic";
 import { resolveEnvironmentOptionLabel } from "./BranchToolbar.logic";
-import { isSidebarHiddenThread } from "./Sidebar.logic";
 import { CommandPaletteContent, type PendingInputSelection } from "./CommandPaletteContent";
 import {
   selectCommandPaletteClientSettings,
@@ -516,8 +516,16 @@ function OpenCommandPaletteDialog(props: {
     if (activeThreadReferenceCopyTarget === null) return;
     await copyThreadReference(activeThreadReferenceCopyTarget);
   };
-  // Side chats and subagents open inside their parent, so opening a project never lands on one.
-  const threads = useVisibleThreadShells().filter((thread) => !isSidebarHiddenThread(thread));
+  // Threads the sidebar shows under their parent open there, so opening a project never lands on one.
+  const delegatedUnderParent = useDelegatedUnderParent();
+  const threads = useVisibleThreadShells().filter(
+    (thread) =>
+      !isShownUnderParent(
+        { environmentId: thread.environmentId, threadId: thread.id },
+        thread.lineage,
+        delegatedUnderParent,
+      ),
+  );
   const keybindings = useAtomValue(primaryServerKeybindingsAtom);
   const providersByEnvironment = useEnvironmentProviders();
   const { changeThemeItem, changeAppearanceItem, themeEditorItem } = useCommandPaletteThemeItems();
diff --git a/apps/web/src/components/Sidebar.logic.test.ts b/apps/web/src/components/Sidebar.logic.test.ts
index b89aa1621a0f..9705bf84e73e 100644
--- a/apps/web/src/components/Sidebar.logic.test.ts
+++ b/apps/web/src/components/Sidebar.logic.test.ts
@@ -1,4 +1,5 @@
 import { presentThreadShell } from "@t3tools/client-runtime/state/models";
+import { threadKey } from "@t3tools/client-runtime/state/entities";
 import { isThreadWorking as isSidebarThreadWorking } from "@t3tools/client-runtime/state/thread-inbox";
 import * as DateTime from "effect/DateTime";
 import { deriveActiveWorkStartedAt } from "../session-logic.ts";
@@ -678,6 +679,7 @@ describe("getFallbackThreadIdAfterDelete", () => {
       deletedThreadIds: new Set([ThreadId.make("thread-active"), ThreadId.make("thread-newest")]),
       sortOrder: "created_at",
       now: "2026-03-09T10:10:00.000Z",
+      delegatedUnderParent: new Set(),
     });
 
     expect(fallbackThreadId).toBe(ThreadId.make("thread-next"));
@@ -688,6 +690,7 @@ describe("getFallbackThreadIdAfterDelete", () => {
       "snoozed",
       { snoozedUntil: "2099-01-01T00:00:00.000Z", snoozedAt: "2026-03-09T10:06:00.000Z" },
     ],
+    ["delegated", { id: ThreadId.make("thread-delegated") }],
     ["settled", { settledOverride: "settled", settledAt: "2026-03-09T10:06:00.000Z" }],
     [
       "side chat",
@@ -733,6 +736,12 @@ describe("getFallbackThreadIdAfterDelete", () => {
       deletedThreadId: ThreadId.make("thread-active"),
       sortOrder: "created_at",
       now: "2026-03-09T10:10:00.000Z",
+      delegatedUnderParent: new Set([
+        threadKey({
+          environmentId: localEnvironmentId,
+          threadId: ThreadId.make("thread-delegated"),
+        }),
+      ]),
     });
 
     expect(fallbackThreadId).toBe(ThreadId.make("thread-visible"));
diff --git a/apps/web/src/components/Sidebar.logic.ts b/apps/web/src/components/Sidebar.logic.ts
index 7c96c89d3028..8c0e678ff667 100644
--- a/apps/web/src/components/Sidebar.logic.ts
+++ b/apps/web/src/components/Sidebar.logic.ts
@@ -1319,15 +1319,18 @@ export function getFallbackThreadIdAfterDelete<
     "id" | "projectId" | "createdAt" | "updatedAt" | "settledOverride" | "lineage"
   > &
     ThreadSortInput &
-    ThreadSnoozeShell,
+    ThreadSnoozeShell &
+    Pick<Thread, "environmentId">,
 >(input: {
   threads: readonly T[];
   deletedThreadId: T["id"];
   sortOrder: SidebarThreadSortOrder;
   now: string;
   deletedThreadIds?: ReadonlySet<T["id"]>;
+  delegatedUnderParent: ReadonlySet<string>;
 }): T["id"] | null {
-  const { deletedThreadId, deletedThreadIds, sortOrder, now, threads } = input;
+  const { deletedThreadId, deletedThreadIds, sortOrder, now, threads, delegatedUnderParent } =
+    input;
   const deletedThread = threads.find((thread) => thread.id === deletedThreadId);
   if (!deletedThread) {
     return null;
@@ -1342,7 +1345,11 @@ export function getFallbackThreadIdAfterDelete<
           !deletedThreadIds?.has(thread.id) &&
           thread.settledOverride !== "settled" &&
           !effectiveSnoozed(thread, { now }) &&
-          !isSidebarHiddenThread(thread),
+          !isShownUnderParent(
+            { environmentId: thread.environmentId, threadId: thread.id },
+            thread.lineage,
+            delegatedUnderParent,
+          ),
       ),
       sortOrder,
     )[0]?.id ?? null
diff --git a/apps/web/src/hooks/useThreadActions.permissions.test.ts b/apps/web/src/hooks/useThreadActions.permissions.test.ts
index d1a74e4e894f..c15dc90bb11f 100644
--- a/apps/web/src/hooks/useThreadActions.permissions.test.ts
+++ b/apps/web/src/hooks/useThreadActions.permissions.test.ts
@@ -142,6 +142,7 @@ vi.mock("../state/entities", () => ({
       .filter((thread) => thread.environmentId === environmentId)
       .map((thread) => ({ environmentId, threadId: thread.id })),
   readProject: () => ({ workspaceRoot: "/project" }),
+  readDelegatedUnderParent: () => new Set(),
 }));
 vi.mock("../components/Sidebar.logic", () => ({
   getFallbackThreadIdAfterDelete: () => null,
diff --git a/apps/web/src/hooks/useThreadActions.ts b/apps/web/src/hooks/useThreadActions.ts
index 6a8ce92af5e3..9c5ae260923c 100644
--- a/apps/web/src/hooks/useThreadActions.ts
+++ b/apps/web/src/hooks/useThreadActions.ts
@@ -38,6 +38,7 @@ import { releaseComposerDraftUploads } from "../lib/composerDraftUploads";
 import { announce } from "../lib/announce";
 import { readLocalApi } from "../localApi";
 import {
+  readDelegatedUnderParent,
   readEnvironmentServerConfigLoaded,
   readEnvironmentSupportsAutoSettleOptOut,
   readEnvironmentThreadRefs,
@@ -593,6 +594,7 @@ export function useThreadActions() {
       deletedThreadIds,
       sortOrder: sidebarThreadSortOrder,
       now: new Date().toISOString(),
+      delegatedUnderParent: readDelegatedUnderParent(),
     });
     let navigatedDuringDelete = false;
     // The missing-thread redirect and the index draft replace this entry; any other history
diff --git a/apps/web/src/state/entities.ts b/apps/web/src/state/entities.ts
index 0cb7bbc60093..27168e1ce789 100644
--- a/apps/web/src/state/entities.ts
+++ b/apps/web/src/state/entities.ts
@@ -385,6 +385,10 @@ export function readThreadShells(): ReadonlyArray<EnvironmentThreadShell> {
   return appAtomRegistry.get(environmentThreadShells.threadShellsAtom);
 }
 
+export function readDelegatedUnderParent(): ReadonlySet<string> {
+  return appAtomRegistry.get(environmentThreadShells.delegatedUnderParentAtom);
+}
+
 function shellParentThreadId(
   thread: Pick<OrchestrationV2ThreadShell, "forkedFrom" | "lineage">,
 ): ThreadId | null {