diff --git a/docs/agent-lifecycle.md b/docs/agent-lifecycle.md
index 45c54ca18b..c0aad974f6 100644
--- a/docs/agent-lifecycle.md
+++ b/docs/agent-lifecycle.md
@@ -259,6 +259,27 @@ archived workspace. History navigation must not infer workspace lifecycle from `
 or mutate either lifecycle. The workspace route asks the daemon for authoritative recovery state;
 only the route's explicit Unarchive or Restore action changes the archived workspace.
 
+Workspace archive is undoable from the archived toast, or with Cmd/Ctrl+Z, while the toast is up.
+The daemon runs one archive lane per workspace, shared by every connection
+(`packages/server/src/server/workspace-archive-operations.ts`):
+
+| A request arrives while  | Result                                                    |
+| ------------------------ | --------------------------------------------------------- |
+| an archive runs: archive | joins the running archive                                 |
+| an archive runs: undo    | aborts the archive, waits for it to settle, then restores |
+| an undo runs: archive    | waits for the undo, then archives                         |
+| an undo runs: undo       | joins the running undo                                    |
+
+A request takes its place in the lane before its first `await`. Arrival order decides, so an undo
+sent right behind its archive still cancels it.
+
+An aborted archive stops at its next checkpoint and reports `canceled`; the undo unarchives only
+the agents that archive itself archived. Deleting the worktree directory is the point of no
+return: an undo after it recreates the worktree through workspace recovery. The client shows or
+hides the row by the latest local intent, so a late remove or upsert from a superseded request
+does not flip it back. Tabs and layout are purged only once the undo window closes with the
+archive committed.
+
 History navigation opens the selected agent without changing either archive state. Workspace
 **Restore** recovers only the workspace; the selected archived agent stays open with its callout.
 The agent's **Unarchive** runs the provider's native unarchive hook before interactive resume and
diff --git a/docs/keyboard-shortcuts.md b/docs/keyboard-shortcuts.md
index eac3ee8103..2c1045eb54 100644
--- a/docs/keyboard-shortcuts.md
+++ b/docs/keyboard-shortcuts.md
@@ -84,3 +84,10 @@ its DOM-derived scope.
 Escape interrupts an agent only in the message input or an unclaimed surface.
 A focused terminal excludes that binding. The source leaves terminal Escape alone;
 terminal Escape/Ctrl forwarding is a separate feature.
+
+## Keys shared with text editing
+
+A binding on a key the platform already uses for editing, such as Cmd/Ctrl+Z for
+workspace archive undo, declares `editable: false` and registers its handler with
+`isActive` true only while it has work. An inactive handler leaves the key
+unhandled, so the pipeline skips `preventDefault` and the platform's own undo runs.
diff --git a/packages/app/e2e/browser/workspace-archive-undo.spec.ts b/packages/app/e2e/browser/workspace-archive-undo.spec.ts
new file mode 100644
index 0000000000..90e47aab3c
--- /dev/null
+++ b/packages/app/e2e/browser/workspace-archive-undo.spec.ts
@@ -0,0 +1,186 @@
+import type { Page } from "@playwright/test";
+import { expect, test } from "../support/fixtures";
+import { gotoAppShell } from "../support/helpers/app";
+import {
+  archiveWorkspaceFromDaemon,
+  connectNewWorkspaceDaemonClient,
+  createWorktreeViaDaemon,
+  openProjectViaDaemon,
+} from "../support/helpers/new-workspace";
+import { getServerId } from "../support/helpers/server-id";
+import { expectWorkspaceAbsentFromSidebar } from "../support/helpers/sidebar";
+import { createMockIdleAgent, openWorkspaceWithAgents } from "../support/helpers/archive-tab";
+import { connectSeedClient } from "../support/helpers/seed-client";
+import { createTempGitRepo } from "../support/helpers/workspace";
+import { getWorkspaceTabTestIds } from "../support/helpers/workspace-tabs";
+import {
+  archiveFromRowButton,
+  createGatedTeardown,
+  expectDirectoryPresence,
+  expectHostWorkspaceSettledActive,
+  outlastUndoWindow,
+  pressUndoShortcut,
+  rowArchiveButton,
+  rowKebab,
+  undoButton,
+  workspaceRow,
+  workspaceTitleWidth,
+} from "../support/helpers/workspace-archive-undo";
+import {
+  waitForSidebarHydration,
+  waitForWorkspaceInSidebar,
+} from "../support/helpers/workspace-ui";
+
+test.describe("Workspace archive undo", () => {
+  let client: Awaited<ReturnType<typeof connectNewWorkspaceDaemonClient>>;
+  let tempRepo: { path: string; cleanup: () => Promise<void> };
+  const worktreeDirectories = new Set<string>();
+
+  test.describe.configure({ timeout: 120_000 });
+
+  test.beforeEach(async () => {
+    client = await connectNewWorkspaceDaemonClient();
+    tempRepo = await createTempGitRepo("archive-undo-");
+  });
+
+  test.afterEach(async () => {
+    for (const directory of worktreeDirectories) {
+      await archiveWorkspaceFromDaemon(client, directory).catch(() => undefined);
+    }
+    worktreeDirectories.clear();
+    await client?.close().catch(() => undefined);
+    await tempRepo?.cleanup().catch(() => undefined);
+  });
+
+  async function seedWorktree(page: Page, slug: string) {
+    await openProjectViaDaemon(client, tempRepo.path);
+    const worktree = await createWorktreeViaDaemon(client, {
+      cwd: tempRepo.path,
+      slug: `${slug}-${Date.now()}`,
+    });
+    worktreeDirectories.add(worktree.workspaceDirectory);
+    await gotoAppShell(page);
+    await waitForSidebarHydration(page);
+    await waitForWorkspaceInSidebar(page, {
+      serverId: getServerId(),
+      workspaceId: worktree.workspaceId,
+    });
+    return worktree;
+  }
+
+  test("the hover archive button overlays the title instead of narrowing it", async ({ page }) => {
+    const worktree = await seedWorktree(page, "archive-button-overlay");
+
+    await page.mouse.move(0, 0);
+    await expect(rowArchiveButton(page, worktree.workspaceId)).toHaveCount(0);
+    const restingWidth = await workspaceTitleWidth(page, worktree.workspaceId);
+
+    await workspaceRow(page, worktree.workspaceId).hover();
+    await expect(rowArchiveButton(page, worktree.workspaceId)).toBeVisible();
+    await expect(page.getByTestId("sidebar-workspace-trailing-scrim")).toBeVisible();
+    expect(await workspaceTitleWidth(page, worktree.workspaceId)).toBe(restingWidth);
+
+    const [buttonBox, kebabBox] = await Promise.all([
+      rowArchiveButton(page, worktree.workspaceId).boundingBox(),
+      rowKebab(page, worktree.workspaceId).boundingBox(),
+    ]);
+    expect(buttonBox && kebabBox && buttonBox.x + buttonBox.width <= kebabBox.x).toBe(true);
+  });
+
+  test("Cmd/Ctrl+Z right after archiving keeps the worktree", async ({ page }) => {
+    const worktree = await seedWorktree(page, "archive-undo-shortcut");
+
+    await archiveFromRowButton(page, worktree.workspaceId);
+    await pressUndoShortcut(page);
+
+    await expect(workspaceRow(page, worktree.workspaceId)).toBeVisible();
+    await expect(undoButton(page)).toHaveCount(0);
+    await expectHostWorkspaceSettledActive(client, worktree.workspaceId);
+    // Once the host settled, any remove the canceled archive sent has already arrived.
+    await expect(workspaceRow(page, worktree.workspaceId)).toBeVisible();
+    await expectDirectoryPresence(worktree.workspaceDirectory, true);
+  });
+
+  test("Undo after the worktree was removed recreates it", async ({ page }) => {
+    const worktree = await seedWorktree(page, "archive-undo-recreate");
+
+    await archiveFromRowButton(page, worktree.workspaceId);
+    // Hovering the toast holds it, and with it the undo, open while the archive finishes.
+    await undoButton(page).hover();
+    await expectDirectoryPresence(worktree.workspaceDirectory, false);
+    await undoButton(page).click();
+
+    await expect(workspaceRow(page, worktree.workspaceId)).toBeVisible({ timeout: 30_000 });
+    await expectDirectoryPresence(worktree.workspaceDirectory, true);
+  });
+
+  test("hovering Undo keeps the toast open past its deadline, and its close ends the undo", async ({
+    page,
+  }) => {
+    await page.clock.install({ time: Date.now() });
+    const worktree = await seedWorktree(page, "archive-undo-hold");
+
+    await archiveFromRowButton(page, worktree.workspaceId);
+    await page.getByTestId("workspace-archived-toast").hover({ position: { x: 8, y: 8 } });
+    await undoButton(page).hover();
+    await outlastUndoWindow(page);
+    await expect(undoButton(page)).toBeVisible();
+
+    await page.mouse.move(0, 0);
+    await outlastUndoWindow(page);
+    await expect(undoButton(page)).toHaveCount(0);
+
+    // The toast took the undo with it.
+    await pressUndoShortcut(page);
+    await expectWorkspaceAbsentFromSidebar(page, worktree.workspaceId);
+  });
+
+  test("opening the workspace while its undo is still running keeps its tabs", async ({ page }) => {
+    const teardown = createGatedTeardown();
+    const repo = await createTempGitRepo("archive-undo-tabs-", {
+      paseoConfig: teardown.paseoConfig,
+    });
+    const seedClient = await connectSeedClient();
+    try {
+      await openProjectViaDaemon(client, repo.path);
+      const worktree = await createWorktreeViaDaemon(client, {
+        cwd: repo.path,
+        slug: `archive-undo-tabs-${Date.now()}`,
+      });
+      worktreeDirectories.add(worktree.workspaceDirectory);
+      const target = { cwd: worktree.workspaceDirectory, workspaceId: worktree.workspaceId };
+      const agents = [
+        await createMockIdleAgent(seedClient, { ...target, title: "first" }),
+        await createMockIdleAgent(seedClient, { ...target, title: "second" }),
+      ] as const;
+      await openWorkspaceWithAgents(page, [agents[0], agents[1]]);
+      const tabsBefore = await getWorkspaceTabTestIds(page);
+
+      await archiveFromRowButton(page, worktree.workspaceId);
+      // The archive has taken its agents down and now parks in teardown.
+      await teardown.expectStarted();
+      await undoButton(page).click();
+      await workspaceRow(page, worktree.workspaceId).click();
+
+      for (const agent of agents) {
+        await expect(page.getByTestId(`workspace-tab-agent_${agent.id}`).first()).toBeVisible();
+      }
+      teardown.release();
+      await expectHostWorkspaceSettledActive(client, worktree.workspaceId);
+      await expect.poll(() => getWorkspaceTabTestIds(page)).toEqual(tabsBefore);
+    } finally {
+      teardown.release();
+      await seedClient.close().catch(() => undefined);
+      await repo.cleanup().catch(() => undefined);
+    }
+  });
+
+  test("Cmd/Ctrl+Z without an archive to undo leaves the sidebar alone", async ({ page }) => {
+    const worktree = await seedWorktree(page, "archive-undo-none");
+
+    await pressUndoShortcut(page);
+
+    await expect(undoButton(page)).toHaveCount(0);
+    await expect(workspaceRow(page, worktree.workspaceId)).toBeVisible();
+  });
+});
diff --git a/packages/app/e2e/support/helpers/workspace-archive-undo.ts b/packages/app/e2e/support/helpers/workspace-archive-undo.ts
new file mode 100644
index 0000000000..0eadc58644
--- /dev/null
+++ b/packages/app/e2e/support/helpers/workspace-archive-undo.ts
@@ -0,0 +1,97 @@
+import { existsSync, mkdtempSync, writeFileSync } from "node:fs";
+import { tmpdir } from "node:os";
+import path from "node:path";
+import type { Page } from "@playwright/test";
+import { expect } from "../fixtures";
+import type { connectNewWorkspaceDaemonClient } from "./new-workspace";
+import { getServerId } from "./server-id";
+import { expectWorkspaceAbsentFromSidebar } from "./sidebar";
+
+type DaemonClient = Awaited<ReturnType<typeof connectNewWorkspaceDaemonClient>>;
+
+const UNDO_SHORTCUT = process.platform === "darwin" ? "Meta+Z" : "Control+Z";
+/** The archived toast's lifetime, from `WORKSPACE_ARCHIVE_UNDO_WINDOW_MS`. */
+const UNDO_WINDOW_MS = 6000;
+
+export function workspaceRow(page: Page, workspaceId: string) {
+  return page.getByTestId(`sidebar-workspace-row-${getServerId()}:${workspaceId}`);
+}
+
+export function rowArchiveButton(page: Page, workspaceId: string) {
+  return page.getByTestId(`sidebar-workspace-archive-button-${getServerId()}:${workspaceId}`);
+}
+
+export function rowKebab(page: Page, workspaceId: string) {
+  return page.getByTestId(`sidebar-workspace-kebab-${getServerId()}:${workspaceId}`);
+}
+
+export function undoButton(page: Page) {
+  return page.getByRole("button", { name: /^Undo/ });
+}
+
+export async function workspaceTitleWidth(page: Page, workspaceId: string): Promise<number> {
+  const box = await page
+    .getByTestId(`sidebar-workspace-title-${getServerId()}:${workspaceId}`)
+    .boundingBox();
+  if (!box) throw new Error(`Title of ${workspaceId} is not laid out`);
+  return box.width;
+}
+
+/** Archives a workspace with its row's hover button and waits for the undo toast. */
+export async function archiveFromRowButton(page: Page, workspaceId: string): Promise<void> {
+  page.once("dialog", (dialog) => void dialog.accept());
+  await workspaceRow(page, workspaceId).hover();
+  await rowArchiveButton(page, workspaceId).click();
+  await expectWorkspaceAbsentFromSidebar(page, workspaceId);
+  await expect(undoButton(page)).toBeVisible();
+}
+
+export async function pressUndoShortcut(page: Page): Promise<void> {
+  await page.keyboard.press(UNDO_SHORTCUT);
+}
+
+/** Moves the page clock past the moment an unheld archived toast would have closed. */
+export async function outlastUndoWindow(page: Page): Promise<void> {
+  await page.clock.fastForward(UNDO_WINDOW_MS + 1000);
+}
+
+/** Waits until the host lists the workspace as active with no archive running on it. */
+export async function expectHostWorkspaceSettledActive(
+  client: DaemonClient,
+  workspaceId: string,
+): Promise<void> {
+  await expect
+    .poll(
+      async () => {
+        const { entries } = await client.fetchWorkspaces();
+        const entry = entries.find((candidate) => candidate.id === workspaceId);
+        return entry ? { active: true, archiving: Boolean(entry.archivingAt) } : null;
+      },
+      { timeout: 30_000 },
+    )
+    .toEqual({ active: true, archiving: false });
+}
+
+export async function expectDirectoryPresence(directory: string, present: boolean): Promise<void> {
+  await expect.poll(() => existsSync(directory), { timeout: 30_000 }).toBe(present);
+}
+
+export interface GatedTeardown {
+  /** The `paseo.json` config whose worktree teardown parks until released. */
+  paseoConfig: Record<string, unknown>;
+  expectStarted(): Promise<void>;
+  release(): void;
+}
+
+/** A worktree teardown that parks an archive mid-flight, so an undo lands while it runs. */
+export function createGatedTeardown(): GatedTeardown {
+  const gateDir = mkdtempSync(path.join(tmpdir(), "archive-undo-gate-"));
+  const startedPath = path.join(gateDir, "started");
+  const releasePath = path.join(gateDir, "release");
+  const teardown = `node -e "const fs=require('fs');fs.writeFileSync('${startedPath}','started');const timer=setInterval(()=>{if(fs.existsSync('${releasePath}'))clearInterval(timer)},20)"`;
+  return {
+    paseoConfig: { worktree: { teardown: [teardown] } },
+    expectStarted: () => expectDirectoryPresence(startedPath, true),
+    release: () => writeFileSync(releasePath, "release\n"),
+  };
+}
diff --git a/packages/app/src/app/_layout.tsx b/packages/app/src/app/_layout.tsx
index 8548b4bb76..b4ca122f77 100644
--- a/packages/app/src/app/_layout.tsx
+++ b/packages/app/src/app/_layout.tsx
@@ -55,6 +55,7 @@ import { DesktopWindowControls } from "@/components/desktop/window-controls";
 import { SidebarModelProvider } from "@/components/sidebar/sidebar-model";
 import { WorkspacePinShortcutHandler } from "@/components/workspace-pin-shortcut-handler";
 import { WorkspaceRenameHost } from "@/components/workspace-rename-host";
+import { WorkspaceArchiveUndoShortcutHost } from "@/workspace/archive-undo";
 import { WorkspaceExplorerOpenGesture } from "@/mobile-panels/explorer-open-gesture";
 import { ProviderSettingsHost } from "@/components/provider-settings-host";
 import { WorkspaceSetupDialog } from "@/components/workspace-setup-dialog";
@@ -557,6 +558,7 @@ function AppContainer({ children, chromeEnabled: chromeEnabledOverride }: AppCon
         <PluginCommandCenterActions />
         <WorkspacePinShortcutHandler />
         <WorkspaceRenameHost />
+        <WorkspaceArchiveUndoShortcutHost />
         <CommandCenter />
         <AddProjectFlowHost />
         <HostChooserModal />
diff --git a/packages/app/src/components/sidebar-workspace-list.tsx b/packages/app/src/components/sidebar-workspace-list.tsx
index 5000e1f067..d6a810e74e 100644
--- a/packages/app/src/components/sidebar-workspace-list.tsx
+++ b/packages/app/src/components/sidebar-workspace-list.tsx
@@ -649,6 +649,7 @@ function WorkspaceRowRightGroup({
   const {
     trailingPresentation,
     showKebab: showKebabInSlot,
+    showArchiveButton,
     showScrim,
     renderSlot,
     reserveSlotWidth,
@@ -675,6 +676,8 @@ function WorkspaceRowRightGroup({
           <SidebarWorkspaceTrailingActionOverlay
             visible={kebab.showKebab}
             scrimBackdrop={showScrim ? backdrop : undefined}
+            workspaceKey={workspace.workspaceKey}
+            onArchiveButtonPress={showArchiveButton ? onArchive : undefined}
           >
             {onArchive ? (
               <SidebarWorkspaceMenu
diff --git a/packages/app/src/components/sidebar/sidebar-status-list.tsx b/packages/app/src/components/sidebar/sidebar-status-list.tsx
index ce8ad535c4..ed19b08857 100644
--- a/packages/app/src/components/sidebar/sidebar-status-list.tsx
+++ b/packages/app/src/components/sidebar/sidebar-status-list.tsx
@@ -872,6 +872,7 @@ function StatusWorkspaceRowInnerContent({
         const {
           trailingPresentation,
           showKebab: showKebabInSlot,
+          showArchiveButton,
           showScrim,
           renderSlot,
           reserveSlotWidth,
@@ -951,6 +952,7 @@ function StatusWorkspaceRowInnerContent({
                     trailing={trailing}
                     trailingPresentation={trailingPresentation}
                     showKebab={showKebabInSlot}
+                    showArchiveButton={showArchiveButton}
                     showScrim={showScrim}
                     reserveSlotWidth={reserveSlotWidth}
                     isPinned={isPinned}
@@ -982,6 +984,7 @@ function StatusWorkspaceActionSlot({
   trailing,
   trailingPresentation,
   showKebab,
+  showArchiveButton,
   showScrim,
   reserveSlotWidth,
   isPinned,
@@ -1002,6 +1005,7 @@ function StatusWorkspaceActionSlot({
   trailing: SidebarWorkspaceTrailing;
   trailingPresentation: SidebarWorkspaceTrailingPresentation;
   showKebab: boolean;
+  showArchiveButton: boolean;
   showScrim: boolean;
   reserveSlotWidth: boolean;
   isPinned?: boolean;
@@ -1026,6 +1030,8 @@ function StatusWorkspaceActionSlot({
       <SidebarWorkspaceTrailingActionOverlay
         visible={kebab.showKebab}
         scrimBackdrop={showScrim ? backdrop : undefined}
+        workspaceKey={workspace.workspaceKey}
+        onArchiveButtonPress={showArchiveButton ? onArchive : undefined}
       >
         {kebab.showKebab && onArchive ? (
           <SidebarWorkspaceMenu
diff --git a/packages/app/src/components/sidebar/sidebar-workspace-menu.tsx b/packages/app/src/components/sidebar/sidebar-workspace-menu.tsx
index 64a3099047..f1c2fabcd1 100644
--- a/packages/app/src/components/sidebar/sidebar-workspace-menu.tsx
+++ b/packages/app/src/components/sidebar/sidebar-workspace-menu.tsx
@@ -1,6 +1,6 @@
 import { useMemo, type ComponentProps, type PropsWithChildren, type ReactNode } from "react";
 import { useTranslation } from "react-i18next";
-import { type PressableStateCallbackType } from "react-native";
+import type { PressableStateCallbackType } from "react-native";
 import { StyleSheet, withUnistyles } from "react-native-unistyles";
 import {
   Archive,
@@ -13,6 +13,7 @@ import {
   PinOff,
   Tag,
 } from "lucide-react-native";
+import { PressHighlight } from "@/components/ui/press-highlight";
 import { isWeb } from "@/constants/platform";
 import { getForgePresentation, normalizeForge } from "@/git/forge";
 import type { SidebarWorkspaceEntry } from "@/hooks/use-sidebar-workspaces-list";
@@ -72,6 +73,9 @@ const archiveLeadingIcon = <ThemedArchive size={14} uniProps={foregroundMutedCol
 const pinLeadingIcon = <ThemedPin size={14} uniProps={foregroundMutedColorMapping} />;
 const unpinLeadingIcon = <ThemedPinOff size={14} uniProps={foregroundMutedColorMapping} />;
 
+/** Pointer-only, so it is always the kebab's pointer size. */
+export const ARCHIVE_BUTTON_SIZE = 18;
+
 const triggerIconProps = densityIconProps("sm", foregroundMutedColorMapping);
 const triggerIconHoveredProps = densityIconProps("sm", foregroundColorMapping);
 
@@ -79,6 +83,33 @@ function renderTriggerIcon({ hovered }: { hovered?: boolean }) {
   return <ThemedMoreVertical uniProps={hovered ? triggerIconHoveredProps : triggerIconProps} />;
 }
 
+function renderArchiveIcon({ hovered }: PressableStateCallbackType & { hovered?: boolean }) {
+  return <ThemedArchive uniProps={hovered ? triggerIconHoveredProps : triggerIconProps} />;
+}
+
+/** One-click archive beside the kebab, for pointer rows that reveal it on hover. */
+export function SidebarWorkspaceArchiveButton({
+  workspaceKey,
+  onArchive,
+}: {
+  workspaceKey: string;
+  onArchive: () => void;
+}) {
+  const { t } = useTranslation();
+  return (
+    <PressHighlight
+      hitSlop={4}
+      style={archiveButtonStyle}
+      onPress={onArchive}
+      accessibilityRole={isWeb ? undefined : "button"}
+      accessibilityLabel={t("sidebar.workspace.actions.archiveWorkspace")}
+      testID={`sidebar-workspace-archive-button-${workspaceKey}`}
+    >
+      {renderArchiveIcon}
+    </PressHighlight>
+  );
+}
+
 export interface SidebarWorkspaceMenuProps {
   workspaceKey: string;
   serverId?: string;
@@ -437,6 +468,12 @@ function triggerStyle({ hovered = false }: PressableStateCallbackType & { hovere
   return [styles.trigger, hovered && styles.triggerHovered];
 }
 
+function archiveButtonStyle({
+  hovered = false,
+}: PressableStateCallbackType & { hovered?: boolean }) {
+  return [styles.archiveButton, hovered && styles.triggerHovered];
+}
+
 const styles = StyleSheet.create((theme) => ({
   trigger: {
     // Larger on touch so the kebab is an easy tap target.
@@ -455,4 +492,13 @@ const styles = StyleSheet.create((theme) => ({
   triggerHovered: {
     backgroundColor: theme.colors.surface2,
   },
+  // The kebab's box without its offsets: the archive glyph fills its view box, so it needs
+  // none of the nudging the three dots do. The kebab's marginLeft is the gap between them.
+  archiveButton: {
+    width: ARCHIVE_BUTTON_SIZE,
+    height: ARCHIVE_BUTTON_SIZE,
+    alignItems: "center",
+    justifyContent: "center",
+    borderRadius: 4,
+  },
 }));
diff --git a/packages/app/src/components/sidebar/sidebar-workspace-row-content.tsx b/packages/app/src/components/sidebar/sidebar-workspace-row-content.tsx
index 7fc904f3b3..aef846c4a3 100644
--- a/packages/app/src/components/sidebar/sidebar-workspace-row-content.tsx
+++ b/packages/app/src/components/sidebar/sidebar-workspace-row-content.tsx
@@ -29,7 +29,11 @@ import { shouldRenderSyncedStatusLoader } from "@/utils/status-loader";
 import { StatusRing } from "@/components/status-ring";
 import { resolveSidebarWorkspacePrimaryLabel } from "@/components/sidebar/sidebar-workspace-title";
 import { DensityIcon } from "@/components/ui/density-icon";
-import { TrailingActionScrim } from "@/components/ui/trailing-action-scrim";
+import { SCRIM_WIDTH, TrailingActionScrim } from "@/components/ui/trailing-action-scrim";
+import {
+  ARCHIVE_BUTTON_SIZE,
+  SidebarWorkspaceArchiveButton,
+} from "@/components/sidebar/sidebar-workspace-menu";
 import { useWorkspaceLabelDefinitions } from "@/workspace-labels";
 
 const needsInputColorMapping = (theme: Theme) => ({
@@ -156,7 +160,11 @@ export const SidebarWorkspaceRowContent = memo(function SidebarWorkspaceRowConte
         )}
         <View style={styles.workspaceContentColumn}>
           <View style={styles.workspaceTitleRow}>
-            <Text style={workspaceBranchTextStyle} numberOfLines={1}>
+            <Text
+              style={workspaceBranchTextStyle}
+              numberOfLines={1}
+              testID={`sidebar-workspace-title-${workspace.workspaceKey}`}
+            >
               {workspaceLabel}
             </Text>
             <View style={sidebarWorkspaceRowStyles.rowRight}>{children}</View>
@@ -330,6 +338,8 @@ export const sidebarWorkspaceRowStyles = StyleSheet.create((theme) => ({
     position: "absolute",
     top: 0,
     right: 0,
+    flexDirection: "row",
+    alignItems: "flex-start",
   },
 }));
 
@@ -370,6 +380,7 @@ export function resolveTrailingActionVisibility({
 }): {
   trailingPresentation: SidebarWorkspaceTrailingPresentation;
   showKebab: boolean;
+  showArchiveButton: boolean;
   showScrim: boolean;
   renderSlot: boolean;
   reserveSlotWidth: boolean;
@@ -384,6 +395,9 @@ export function resolveTrailingActionVisibility({
   return {
     trailingPresentation,
     showKebab,
+    // One-click archive is a pointer affordance: on touch it would sit a few pixels from the
+    // kebab and turn a miss into an archive.
+    showArchiveButton: showKebab && isHovered && !isTouchPlatform,
     // The scrim paints the row's own hover background, so it can only be drawn on a hovered
     // row — over an unhovered one the gradient fades to the wrong color. That is also why
     // touch, which shows the kebab without ever hovering, never gets one.
@@ -432,23 +446,46 @@ export function SidebarWorkspaceTrailingActionBase({
   );
 }
 
+// The archive button plus the kebab's marginLeft, which is the gap between them.
+const ARCHIVE_BUTTON_SCRIM_WIDTH = ARCHIVE_BUTTON_SIZE + 2;
+
 export function SidebarWorkspaceTrailingActionOverlay({
   visible,
   scrimBackdrop,
+  workspaceKey,
+  onArchiveButtonPress,
   children,
 }: {
   visible: boolean;
   /** Fade the row into the kebab when something (the diff stat) is still rendered behind it. */
   scrimBackdrop?: SidebarSurfaceBackdrop;
+  workspaceKey: string;
+  /**
+   * Shows the archive button left of the kebab. It overlays the title like the kebab does, so
+   * the scrim widens to cover it rather than the slot reserving its width.
+   */
+  onArchiveButtonPress?: () => void;
   children: ReactNode;
 }) {
   if (!visible || !children) return null;
   return (
     <>
       {scrimBackdrop ? (
-        <TrailingActionScrim backdrop={scrimBackdrop} testID="sidebar-workspace-trailing-scrim" />
+        <TrailingActionScrim
+          backdrop={scrimBackdrop}
+          width={onArchiveButtonPress ? SCRIM_WIDTH + ARCHIVE_BUTTON_SCRIM_WIDTH : SCRIM_WIDTH}
+          testID="sidebar-workspace-trailing-scrim"
+        />
       ) : null}
-      <View style={sidebarWorkspaceRowStyles.trailingActionOverlay}>{children}</View>
+      <View style={sidebarWorkspaceRowStyles.trailingActionOverlay}>
+        {onArchiveButtonPress ? (
+          <SidebarWorkspaceArchiveButton
+            workspaceKey={workspaceKey}
+            onArchive={onArchiveButtonPress}
+          />
+        ) : null}
+        {children}
+      </View>
     </>
   );
 }
diff --git a/packages/app/src/components/sidebar/sidebar-workspace-row.tsx b/packages/app/src/components/sidebar/sidebar-workspace-row.tsx
index 2488e7956e..d458b390ed 100644
--- a/packages/app/src/components/sidebar/sidebar-workspace-row.tsx
+++ b/packages/app/src/components/sidebar/sidebar-workspace-row.tsx
@@ -404,6 +404,7 @@ function WorkspaceRowTrailingActions({
   const {
     trailingPresentation,
     showKebab: showKebabInSlot,
+    showArchiveButton,
     showScrim,
     renderSlot,
     reserveSlotWidth,
@@ -430,6 +431,8 @@ function WorkspaceRowTrailingActions({
           <SidebarWorkspaceTrailingActionOverlay
             visible={kebab.showKebab}
             scrimBackdrop={showScrim ? backdrop : undefined}
+            workspaceKey={workspace.workspaceKey}
+            onArchiveButtonPress={showArchiveButton ? onArchive : undefined}
           >
             {onArchive ? (
               <SidebarWorkspaceMenu
diff --git a/packages/app/src/components/toast-host.tsx b/packages/app/src/components/toast-host.tsx
index 62a15bad04..81020210d9 100644
--- a/packages/app/src/components/toast-host.tsx
+++ b/packages/app/src/components/toast-host.tsx
@@ -35,6 +35,8 @@ export interface ToastShowOptions {
   durationMs?: number | null;
   nativeAndroid?: boolean;
   testID?: string;
+  /** Runs once when this toast leaves the screen: timed out, dismissed, or replaced. */
+  onDismiss?: () => void;
 }
 
 export interface ToastState {
@@ -45,6 +47,7 @@ export interface ToastState {
   variant: ToastVariant;
   durationMs: number | null;
   testID?: string;
+  onDismiss?: () => void;
 }
 
 /** Dismisses the toast it was returned for; a no-op once another toast replaced it. */
@@ -78,40 +81,56 @@ export function useToastHost(): {
   dismiss: () => void;
 } {
   const { t } = useTranslation();
-  const [toast, setToast] = useState<ToastState | null>(null);
+  const [toast, setToastState] = useState<ToastState | null>(null);
+  const toastRef = useRef<ToastState | null>(null);
   const idRef = useRef(0);
 
-  const show = useCallback((content: ReactNode, options?: ToastShowOptions): DismissToast => {
-    const nativeMessage = typeof content === "string" ? content.trim() : null;
-    if (!content || nativeMessage === "") {
-      return noopDismiss;
-    }
-
-    const variant = options?.variant ?? "default";
-    const durationMs = options?.durationMs === undefined ? DEFAULT_DURATION_MS : options.durationMs;
-    const nativeAndroid = options?.nativeAndroid ?? false;
-
-    if (Platform.OS === "android" && nativeAndroid && nativeMessage) {
-      const duration =
-        durationMs !== null && durationMs <= 2500 ? ToastAndroid.SHORT : ToastAndroid.LONG;
-      ToastAndroid.showWithGravity(nativeMessage, duration, ToastAndroid.TOP);
-      return noopDismiss;
-    }
-
-    idRef.current += 1;
-    const id = idRef.current;
-    setToast({
-      id,
-      content,
-      nativeMessage,
-      icon: options?.icon,
-      variant,
-      durationMs,
-      testID: options?.testID,
-    });
-    return () => setToast((current) => (current?.id === id ? null : current));
+  const setToast = useCallback((next: ToastState | null) => {
+    const previous = toastRef.current;
+    if (previous === next) return;
+    toastRef.current = next;
+    setToastState(next);
+    previous?.onDismiss?.();
   }, []);
 
+  const show = useCallback(
+    (content: ReactNode, options?: ToastShowOptions): DismissToast => {
+      const nativeMessage = typeof content === "string" ? content.trim() : null;
+      if (!content || nativeMessage === "") {
+        return noopDismiss;
+      }
+
+      const variant = options?.variant ?? "default";
+      const durationMs =
+        options?.durationMs === undefined ? DEFAULT_DURATION_MS : options.durationMs;
+      const nativeAndroid = options?.nativeAndroid ?? false;
+
+      if (Platform.OS === "android" && nativeAndroid && nativeMessage) {
+        const duration =
+          durationMs !== null && durationMs <= 2500 ? ToastAndroid.SHORT : ToastAndroid.LONG;
+        ToastAndroid.showWithGravity(nativeMessage, duration, ToastAndroid.TOP);
+        return noopDismiss;
+      }
+
+      idRef.current += 1;
+      const id = idRef.current;
+      setToast({
+        id,
+        content,
+        nativeMessage,
+        icon: options?.icon,
+        variant,
+        durationMs,
+        testID: options?.testID,
+        onDismiss: options?.onDismiss,
+      });
+      return () => {
+        if (toastRef.current?.id === id) setToast(null);
+      };
+    },
+    [setToast],
+  );
+
   const api = useMemo<ToastApi>(
     () => ({
       show,
@@ -127,7 +146,7 @@ export function useToastHost(): {
 
   const dismiss = useCallback(() => {
     setToast(null);
-  }, []);
+  }, [setToast]);
 
   return { api, toast, dismiss };
 }
diff --git a/packages/app/src/components/ui/trailing-action-scrim.tsx b/packages/app/src/components/ui/trailing-action-scrim.tsx
index e106bf3ec5..0b43136bd1 100644
--- a/packages/app/src/components/ui/trailing-action-scrim.tsx
+++ b/packages/app/src/components/ui/trailing-action-scrim.tsx
@@ -6,9 +6,18 @@ import type { SurfaceBackdrop } from "@/styles/surface-backdrop";
 import type { Theme } from "@/styles/theme";
 
 export const SCRIM_WIDTH = 48;
-const SCRIM_SOLID_OFFSET = "55%";
+// The fade is a fixed length so a wider scrim only adds solid surface under its actions.
+const SCRIM_FADE_WIDTH = SCRIM_WIDTH * 0.55;
 
-function TrailingActionScrimSvg({ gradientId, color }: { gradientId: string; color: string }) {
+function TrailingActionScrimSvg({
+  gradientId,
+  color,
+  solidOffset,
+}: {
+  gradientId: string;
+  color: string;
+  solidOffset: string;
+}) {
   return (
     <Svg width="100%" height="100%" preserveAspectRatio="none">
       <Defs>
@@ -16,7 +25,7 @@ function TrailingActionScrimSvg({ gradientId, color }: { gradientId: string; col
           {/* Vary opacity rather than interpolating toward `transparent`, which crosses black in
               some engines and leaves a grey fringe. */}
           <Stop offset="0%" stopColor={color} stopOpacity={0} />
-          <Stop offset={SCRIM_SOLID_OFFSET} stopColor={color} stopOpacity={1} />
+          <Stop offset={solidOffset} stopColor={color} stopOpacity={1} />
           <Stop offset="100%" stopColor={color} stopOpacity={1} />
         </SvgLinearGradient>
       </Defs>
@@ -39,17 +48,22 @@ const backdropColorMappings: Record<SurfaceBackdrop, (theme: Theme) => { color:
 /** Fades trailing content into the surface beneath an absolutely overlaid action. */
 export function TrailingActionScrim({
   backdrop,
+  width = SCRIM_WIDTH,
   testID,
 }: {
   backdrop: SurfaceBackdrop;
+  /** Covers more than one trailing action; the fade keeps its length. */
+  width?: number;
   testID?: string;
 }) {
   // React-generated ids contain characters that are invalid inside SVG fragment references.
   const gradientId = `trailing-action-scrim-${useId().replace(/[^a-zA-Z0-9_-]/g, "")}`;
+  const solidOffset = `${Math.round((SCRIM_FADE_WIDTH / width) * 100)}%`;
   return (
-    <View style={styles.scrim} pointerEvents="none" testID={testID}>
+    <View style={styles.scrim(width)} pointerEvents="none" testID={testID}>
       <ThemedTrailingActionScrimSvg
         gradientId={gradientId}
+        solidOffset={solidOffset}
         uniProps={backdropColorMappings[backdrop]}
       />
     </View>
@@ -57,11 +71,11 @@ export function TrailingActionScrim({
 }
 
 const styles = StyleSheet.create({
-  scrim: {
+  scrim: (width: number) => ({
     position: "absolute",
     top: 0,
     bottom: 0,
     right: 0,
-    width: SCRIM_WIDTH,
-  },
+    width,
+  }),
 });
diff --git a/packages/app/src/contexts/session-workspace-upserts.test.ts b/packages/app/src/contexts/session-workspace-upserts.test.ts
index c0c3bea91f..7e942f234b 100644
--- a/packages/app/src/contexts/session-workspace-upserts.test.ts
+++ b/packages/app/src/contexts/session-workspace-upserts.test.ts
@@ -4,7 +4,10 @@ import {
   clearWorkspaceArchivePending,
   isWorkspaceArchivePending,
   markWorkspaceArchivePending,
+  markWorkspaceArchiveUndoPending,
   shouldSuppressWorkspaceForLocalArchive,
+  settleWorkspaceArchiveIntent,
+  shouldSuppressWorkspaceRemovalForLocalUndo,
 } from "@/contexts/session-workspace-upserts";
 
 const baseWorkspace: WorkspaceDescriptor = {
@@ -116,3 +119,41 @@ describe("workspace archive pending suppression", () => {
     clearWorkspaceArchivePending({ serverId: "server-1", workspaceId: "/repo/worktree" });
   });
 });
+
+describe("workspace archive undo intent", () => {
+  const target = { serverId: "server-1", workspaceId: "/repo/worktree" };
+
+  it("lets host upserts through and holds host removes while an undo is pending", () => {
+    markWorkspaceArchivePending(target);
+    const undo = markWorkspaceArchiveUndoPending(target);
+
+    expect({
+      upsertSuppressed: shouldSuppressWorkspaceForLocalArchive({
+        serverId: target.serverId,
+        workspace: workspace({ archivingAt: null }),
+      }),
+      removeSuppressed: shouldSuppressWorkspaceRemovalForLocalUndo(target),
+    }).toEqual({ upsertSuppressed: false, removeSuppressed: true });
+
+    settleWorkspaceArchiveIntent(undo);
+    expect(shouldSuppressWorkspaceRemovalForLocalUndo(target)).toBe(false);
+  });
+
+  it("keeps a newer intent when the request behind an older one settles late", () => {
+    const firstArchive = markWorkspaceArchivePending(target);
+    const firstUndo = markWorkspaceArchiveUndoPending(target);
+    settleWorkspaceArchiveIntent(firstArchive);
+    clearWorkspaceArchivePending(target);
+    expect(shouldSuppressWorkspaceRemovalForLocalUndo(target)).toBe(true);
+
+    markWorkspaceArchivePending(target);
+    settleWorkspaceArchiveIntent(firstUndo);
+    expect(isWorkspaceArchivePending(target)).toBe(true);
+
+    const secondUndo = markWorkspaceArchiveUndoPending(target);
+    settleWorkspaceArchiveIntent(firstUndo);
+    expect(shouldSuppressWorkspaceRemovalForLocalUndo(target)).toBe(true);
+
+    settleWorkspaceArchiveIntent(secondUndo);
+  });
+});
diff --git a/packages/app/src/contexts/session-workspace-upserts.ts b/packages/app/src/contexts/session-workspace-upserts.ts
index 1b4279631f..2957a90b0d 100644
--- a/packages/app/src/contexts/session-workspace-upserts.ts
+++ b/packages/app/src/contexts/session-workspace-upserts.ts
@@ -1,77 +1,142 @@
 import type { WorkspaceDescriptor } from "@/stores/session-store";
 import { normalizeWorkspaceOpaqueId } from "@/utils/workspace-identity";
 
-interface PendingWorkspaceArchive {
-  workspaceId: string;
+/**
+ * What this client last asked the host to do with a workspace, while the host catches up.
+ *
+ * - `archive`: the row is hidden; host upserts for it are dropped until its remove arrives.
+ * - `undo`: the row is back; host removes for it are dropped until the undo response arrives.
+ *
+ * Each request gets its own intent. A request settles or checks only the intent it set, so a
+ * late response for an earlier request never touches the intent of a newer one.
+ */
+export interface WorkspaceArchiveIntent {
+  readonly kind: "archive" | "undo";
 }
 
-const pendingWorkspaceArchivesByServer = new Map<string, Map<string, PendingWorkspaceArchive>>();
+const intentsByServer = new Map<string, Map<string, WorkspaceArchiveIntent>>();
+const intentListeners = new Set<() => void>();
+const targetByIntent = new WeakMap<
+  WorkspaceArchiveIntent,
+  { serverId: string; workspaceId: string }
+>();
 
-function pendingArchiveKey(input: { serverId: string; workspaceId: string }): string {
-  return `${input.serverId.trim()}::${input.workspaceId.trim()}`;
+interface WorkspaceIntentTarget {
+  serverId: string;
+  workspaceId?: string | null;
+}
+
+function resolveTarget(
+  input: WorkspaceIntentTarget,
+): { serverId: string; workspaceId: string } | null {
+  const serverId = input.serverId.trim();
+  const workspaceId = normalizeWorkspaceOpaqueId(input.workspaceId);
+  if (!serverId || !workspaceId) return null;
+  return { serverId, workspaceId };
+}
+
+function readIntent(input: WorkspaceIntentTarget): WorkspaceArchiveIntent | null {
+  const target = resolveTarget(input);
+  if (!target) return null;
+  return intentsByServer.get(target.serverId)?.get(target.workspaceId) ?? null;
+}
+
+function setIntent(
+  input: WorkspaceIntentTarget,
+  kind: WorkspaceArchiveIntent["kind"],
+): WorkspaceArchiveIntent {
+  const intent: WorkspaceArchiveIntent = { kind };
+  const target = resolveTarget(input);
+  if (!target) return intent;
+  targetByIntent.set(intent, target);
+  const intents = intentsByServer.get(target.serverId) ?? new Map();
+  intents.set(target.workspaceId, intent);
+  intentsByServer.set(target.serverId, intents);
+  notifyIntentListeners();
+  return intent;
+}
+
+function deleteIntent(target: { serverId: string; workspaceId: string }): void {
+  const intents = intentsByServer.get(target.serverId);
+  if (!intents) return;
+  intents.delete(target.workspaceId);
+  if (intents.size === 0) intentsByServer.delete(target.serverId);
+  notifyIntentListeners();
+}
+
+function notifyIntentListeners(): void {
+  for (const listener of intentListeners) listener();
+}
+
+/** Calls `listener` whenever any workspace's archive intent changes. */
+export function subscribeWorkspaceArchiveIntents(listener: () => void): () => void {
+  intentListeners.add(listener);
+  return () => {
+    intentListeners.delete(listener);
+  };
+}
+
+function clearIntentOfKind(
+  input: WorkspaceIntentTarget,
+  kind: WorkspaceArchiveIntent["kind"],
+): void {
+  const target = resolveTarget(input);
+  if (!target || readIntent(target)?.kind !== kind) return;
+  deleteIntent(target);
+}
+
+/** True while `intent` is still the latest thing this client asked for its workspace. */
+export function isWorkspaceArchiveIntentCurrent(intent: WorkspaceArchiveIntent): boolean {
+  const target = targetByIntent.get(intent);
+  return target !== undefined && readIntent(target) === intent;
+}
+
+/** The request behind `intent` settled. A newer request's intent stays in place. */
+export function settleWorkspaceArchiveIntent(intent: WorkspaceArchiveIntent): void {
+  const target = targetByIntent.get(intent);
+  if (target && readIntent(target) === intent) deleteIntent(target);
 }
 
 export function markWorkspaceArchivePending(input: {
   serverId: string;
   workspaceId: string;
-}): void {
-  const serverId = input.serverId.trim();
-  const workspaceId = normalizeWorkspaceOpaqueId(input.workspaceId);
-  if (!serverId || !workspaceId) {
-    return;
-  }
-
-  const archives = pendingWorkspaceArchivesByServer.get(serverId) ?? new Map();
-  archives.set(pendingArchiveKey({ serverId, workspaceId }), {
-    workspaceId,
-  });
-  pendingWorkspaceArchivesByServer.set(serverId, archives);
+}): WorkspaceArchiveIntent {
+  return setIntent(input, "archive");
 }
 
+/** The host removed the workspace, which settles whichever archive this client has pending. */
 export function clearWorkspaceArchivePending(input: {
   serverId: string;
   workspaceId: string;
 }): void {
-  const serverId = input.serverId.trim();
-  const workspaceId = normalizeWorkspaceOpaqueId(input.workspaceId);
-  if (!serverId || !workspaceId) {
-    return;
-  }
-
-  const archives = pendingWorkspaceArchivesByServer.get(serverId);
-  if (!archives) {
-    return;
-  }
-  archives.delete(pendingArchiveKey({ serverId, workspaceId }));
-  if (archives.size === 0) {
-    pendingWorkspaceArchivesByServer.delete(serverId);
-  }
+  clearIntentOfKind(input, "archive");
 }
 
-export function isWorkspaceArchivePending(input: {
+export function isWorkspaceArchivePending(input: WorkspaceIntentTarget): boolean {
+  return readIntent(input)?.kind === "archive";
+}
+
+export function markWorkspaceArchiveUndoPending(input: {
   serverId: string;
-  workspaceId?: string | null;
-}): boolean {
-  const serverId = input.serverId.trim();
-  if (!serverId) {
-    return false;
-  }
+  workspaceId: string;
+}): WorkspaceArchiveIntent {
+  return setIntent(input, "undo");
+}
 
-  const archives = pendingWorkspaceArchivesByServer.get(serverId);
-  if (!archives) {
-    return false;
-  }
-
-  const workspaceId = normalizeWorkspaceOpaqueId(input.workspaceId);
-  return Boolean(workspaceId && archives.has(pendingArchiveKey({ serverId, workspaceId })));
+export function isWorkspaceArchiveUndoPending(input: WorkspaceIntentTarget): boolean {
+  return readIntent(input)?.kind === "undo";
 }
 
 export function shouldSuppressWorkspaceForLocalArchive(input: {
   serverId: string;
   workspace: WorkspaceDescriptor;
 }): boolean {
-  return isWorkspaceArchivePending({
-    serverId: input.serverId,
-    workspaceId: input.workspace.id,
-  });
+  return isWorkspaceArchivePending({ serverId: input.serverId, workspaceId: input.workspace.id });
+}
+
+export function shouldSuppressWorkspaceRemovalForLocalUndo(input: {
+  serverId: string;
+  workspaceId: string;
+}): boolean {
+  return isWorkspaceArchiveUndoPending(input);
 }
diff --git a/packages/app/src/i18n/resources/ar.ts b/packages/app/src/i18n/resources/ar.ts
index f86d81b6e9..fda62bd508 100644
--- a/packages/app/src/i18n/resources/ar.ts
+++ b/packages/app/src/i18n/resources/ar.ts
@@ -1341,6 +1341,9 @@ export const ar: TranslationResources = {
         hostDisconnected: "Host غير متصل",
         hideFailed: "فشل في إخفاء مساحة العمل",
         archiveFailed: "فشل في أرشفة مساحة العمل",
+        archived: "تمت أرشفة مساحة العمل",
+        undoArchive: "تراجع",
+        undoArchiveFailed: "تعذّر التراجع عن الأرشفة",
       },
     },
   },
diff --git a/packages/app/src/i18n/resources/en.ts b/packages/app/src/i18n/resources/en.ts
index 103a981abc..79baa3a48c 100644
--- a/packages/app/src/i18n/resources/en.ts
+++ b/packages/app/src/i18n/resources/en.ts
@@ -1349,6 +1349,9 @@ export const en = {
         hostDisconnected: "Host is not connected",
         hideFailed: "Failed to hide workspace",
         archiveFailed: "Failed to archive workspace",
+        archived: "Workspace archived",
+        undoArchive: "Undo",
+        undoArchiveFailed: "Couldn't undo the archive",
       },
     },
   },
diff --git a/packages/app/src/i18n/resources/es.ts b/packages/app/src/i18n/resources/es.ts
index 48737ee20e..2841ec345f 100644
--- a/packages/app/src/i18n/resources/es.ts
+++ b/packages/app/src/i18n/resources/es.ts
@@ -1377,6 +1377,9 @@ export const es: TranslationResources = {
         hostDisconnected: "Hostno está conectado",
         hideFailed: "No se pudo ocultar el espacio de trabajo",
         archiveFailed: "No se pudo archivar el espacio de trabajo",
+        archived: "Espacio de trabajo archivado",
+        undoArchive: "Deshacer",
+        undoArchiveFailed: "No se pudo deshacer el archivado",
       },
     },
   },
diff --git a/packages/app/src/i18n/resources/fr.ts b/packages/app/src/i18n/resources/fr.ts
index 0d2e4aabce..9324fa84c8 100644
--- a/packages/app/src/i18n/resources/fr.ts
+++ b/packages/app/src/i18n/resources/fr.ts
@@ -1371,6 +1371,9 @@ export const fr: TranslationResources = {
         hostDisconnected: "L’hôte n’est pas connecté",
         hideFailed: "Impossible de masquer l’espace de travail",
         archiveFailed: "Impossible d’archiver l’espace de travail",
+        archived: "Espace de travail archivé",
+        undoArchive: "Annuler",
+        undoArchiveFailed: "Impossible d’annuler l’archivage",
       },
     },
   },
diff --git a/packages/app/src/i18n/resources/ja.ts b/packages/app/src/i18n/resources/ja.ts
index ca93aa3106..58c2ec59df 100644
--- a/packages/app/src/i18n/resources/ja.ts
+++ b/packages/app/src/i18n/resources/ja.ts
@@ -1355,6 +1355,9 @@ export const ja: TranslationResources = {
         hostDisconnected: "ホストが接続されていません",
         hideFailed: "ワークスペースの非表示に失敗しました",
         archiveFailed: "ワークスペースのアーカイブに失敗しました",
+        archived: "ワークスペースをアーカイブしました",
+        undoArchive: "元に戻す",
+        undoArchiveFailed: "アーカイブを元に戻せませんでした",
       },
     },
   },
diff --git a/packages/app/src/i18n/resources/ko.ts b/packages/app/src/i18n/resources/ko.ts
index 51ea225983..12e2909ddc 100644
--- a/packages/app/src/i18n/resources/ko.ts
+++ b/packages/app/src/i18n/resources/ko.ts
@@ -1348,6 +1348,9 @@ export const ko: TranslationResources = {
         hostDisconnected: "호스트가 연결되어 있지 않습니다",
         hideFailed: "워크스페이스를 숨기지 못했습니다",
         archiveFailed: "워크스페이스를 보관하지 못했습니다.",
+        archived: "워크스페이스를 보관했습니다",
+        undoArchive: "실행 취소",
+        undoArchiveFailed: "보관을 취소하지 못했습니다",
       },
     },
   },
diff --git a/packages/app/src/i18n/resources/pt-BR.ts b/packages/app/src/i18n/resources/pt-BR.ts
index 5c2695f3bf..88f400907d 100644
--- a/packages/app/src/i18n/resources/pt-BR.ts
+++ b/packages/app/src/i18n/resources/pt-BR.ts
@@ -1367,6 +1367,9 @@ export const ptBR: TranslationResources = {
         hostDisconnected: "Host não está conectado",
         hideFailed: "Falha ao ocultar workspace",
         archiveFailed: "Falha ao arquivar workspace",
+        archived: "Workspace arquivado",
+        undoArchive: "Desfazer",
+        undoArchiveFailed: "Não foi possível desfazer o arquivamento",
       },
     },
   },
diff --git a/packages/app/src/i18n/resources/ru.ts b/packages/app/src/i18n/resources/ru.ts
index ea8fb1eb25..abab6a8395 100644
--- a/packages/app/src/i18n/resources/ru.ts
+++ b/packages/app/src/i18n/resources/ru.ts
@@ -1359,6 +1359,9 @@ export const ru: TranslationResources = {
         hostDisconnected: "Хост не подключён",
         hideFailed: "Не удалось скрыть рабочее пространство",
         archiveFailed: "Не удалось архивировать рабочее пространство",
+        archived: "Рабочее пространство архивировано",
+        undoArchive: "Отменить",
+        undoArchiveFailed: "Не удалось отменить архивацию",
       },
     },
   },
diff --git a/packages/app/src/i18n/resources/zh-CN.ts b/packages/app/src/i18n/resources/zh-CN.ts
index 54454d9bff..3a1c9bf29b 100644
--- a/packages/app/src/i18n/resources/zh-CN.ts
+++ b/packages/app/src/i18n/resources/zh-CN.ts
@@ -1330,6 +1330,9 @@ export const zhCN: TranslationResources = {
         hostDisconnected: "Host 未连接",
         hideFailed: "隐藏 workspace 失败",
         archiveFailed: "归档工作区失败",
+        archived: "工作区已归档",
+        undoArchive: "撤销",
+        undoArchiveFailed: "无法撤销归档",
       },
     },
   },
diff --git a/packages/app/src/keyboard/actions.ts b/packages/app/src/keyboard/actions.ts
index 1bf78d923f..ef656a40a5 100644
--- a/packages/app/src/keyboard/actions.ts
+++ b/packages/app/src/keyboard/actions.ts
@@ -52,6 +52,7 @@ export type KeyboardActionId =
   | "workspace.project.pick"
   | "worktree.new"
   | "workspace.archive"
+  | "workspace.archive.undo"
   | "workspace.pin"
   | "view.toggle.focus"
   | "theme.cycle"
diff --git a/packages/app/src/keyboard/keyboard-action-dispatcher.ts b/packages/app/src/keyboard/keyboard-action-dispatcher.ts
index a3f2b4c515..ba27e4b354 100644
--- a/packages/app/src/keyboard/keyboard-action-dispatcher.ts
+++ b/packages/app/src/keyboard/keyboard-action-dispatcher.ts
@@ -51,6 +51,7 @@ export type KeyboardActionId =
   | "workspace.project.pick"
   | "worktree.new"
   | "workspace.archive"
+  | "workspace.archive.undo"
   | "workspace.pin"
   // Command-center only: no keybind, so these are absent from route-shortcut.ts.
   | "workspace.rename"
@@ -109,6 +110,7 @@ export type KeyboardActionDefinition =
   | { id: "workspace.project.pick"; scope: KeyboardActionScope }
   | { id: "worktree.new"; scope: KeyboardActionScope }
   | { id: "workspace.archive"; scope: KeyboardActionScope }
+  | { id: "workspace.archive.undo"; scope: KeyboardActionScope }
   | { id: "workspace.pin"; scope: KeyboardActionScope }
   | { id: "workspace.rename"; scope: KeyboardActionScope }
   | { id: "workspace.setup.show"; scope: KeyboardActionScope };
diff --git a/packages/app/src/keyboard/keyboard-shortcuts.test.ts b/packages/app/src/keyboard/keyboard-shortcuts.test.ts
index 29179901ee..9eddf4b5b5 100644
--- a/packages/app/src/keyboard/keyboard-shortcuts.test.ts
+++ b/packages/app/src/keyboard/keyboard-shortcuts.test.ts
@@ -408,6 +408,25 @@ describe("keyboard-shortcuts", () => {
     },
   );
 
+  describe("undo archive workspace", () => {
+    it.each([
+      { isMac: true, event: { key: "z", code: "KeyZ", metaKey: true } },
+      { isMac: false, event: { key: "z", code: "KeyZ", ctrlKey: true } },
+    ])("routes Cmd/Ctrl+Z outside text and terminals (mac: $isMac)", ({ isMac, event }) => {
+      expectShortcutResolution({ event, context: { isMac }, action: "workspace.archive.undo" });
+    });
+
+    it.each(["editable", "message-input", "terminal"] as const)(
+      "leaves Cmd+Z to the focused %s",
+      (focusScope) => {
+        expectNoShortcutResolution({
+          event: { key: "z", code: "KeyZ", metaKey: true },
+          context: { isMac: true, focusScope },
+        });
+      },
+    );
+  });
+
   it("leaves Escape to an editable field", () => {
     expectNoShortcutResolution({
       event: { key: "Escape", code: "Escape" },
diff --git a/packages/app/src/keyboard/keyboard-shortcuts.ts b/packages/app/src/keyboard/keyboard-shortcuts.ts
index b55e78fc25..d6db467da3 100644
--- a/packages/app/src/keyboard/keyboard-shortcuts.ts
+++ b/packages/app/src/keyboard/keyboard-shortcuts.ts
@@ -169,6 +169,7 @@ export const SHORTCUT_HELP_ROW_ORDER: Record<ShortcutSectionId, readonly string[
     "workspace-next",
     "pin-workspace",
     "archive-workspace",
+    "undo-archive-workspace",
   ],
   "tabs-panes": [
     "workspace-tab-new",
@@ -361,6 +362,31 @@ const SHORTCUT_BINDINGS: readonly ShortcutBinding[] = [
     },
   },
 
+  // --- Undo archive workspace ---
+  // Only claims the key while an archive can be undone; otherwise text undo runs as usual.
+  {
+    id: "workspace-archive-undo-cmd-z-mac",
+    action: "workspace.archive.undo",
+    combo: "Cmd+Z",
+    when: { mac: true, commandCenter: false, editable: false, terminal: false },
+    help: {
+      id: "undo-archive-workspace",
+      section: "workspaces",
+      label: "Undo archive workspace",
+    },
+  },
+  {
+    id: "workspace-archive-undo-ctrl-z-non-mac",
+    action: "workspace.archive.undo",
+    combo: "Ctrl+Z",
+    when: { mac: false, commandCenter: false, editable: false, terminal: false },
+    help: {
+      id: "undo-archive-workspace",
+      section: "workspaces",
+      label: "Undo archive workspace",
+    },
+  },
+
   // --- Pin workspace ---
   {
     id: "workspace-pin-cmd-shift-p-mac",
diff --git a/packages/app/src/keyboard/route-shortcut.ts b/packages/app/src/keyboard/route-shortcut.ts
index aa7679a7bf..79579689fd 100644
--- a/packages/app/src/keyboard/route-shortcut.ts
+++ b/packages/app/src/keyboard/route-shortcut.ts
@@ -48,6 +48,7 @@ const PASSTHROUGH_DISPATCH: Record<string, KeyboardActionDefinition> = {
   "workspace.new": { id: "workspace.new", scope: "sidebar" },
   "workspace.project.pick": { id: "workspace.project.pick", scope: "workspace" },
   "workspace.archive": { id: "workspace.archive", scope: "sidebar" },
+  "workspace.archive.undo": { id: "workspace.archive.undo", scope: "global" },
   "workspace.pin": { id: "workspace.pin", scope: "sidebar" },
   "worktree.new": { id: "worktree.new", scope: "sidebar" },
   "workspace.terminal.new": { id: "workspace.terminal.new", scope: "workspace" },
diff --git a/packages/app/src/runtime/directory-sync/workspace-replica.test.ts b/packages/app/src/runtime/directory-sync/workspace-replica.test.ts
index 792c005100..e3aa345d74 100644
--- a/packages/app/src/runtime/directory-sync/workspace-replica.test.ts
+++ b/packages/app/src/runtime/directory-sync/workspace-replica.test.ts
@@ -9,6 +9,8 @@ import {
 import {
   clearWorkspaceArchivePending,
   markWorkspaceArchivePending,
+  markWorkspaceArchiveUndoPending,
+  settleWorkspaceArchiveIntent,
 } from "@/contexts/session-workspace-upserts";
 import { useWorkspaceSetupStore } from "@/stores/workspace-setup-store";
 import { WorkspaceDirectoryReplica } from "./workspace-replica";
@@ -378,3 +380,53 @@ it("restores a missing workspace after an archive failure without replacing a li
     store.clearSession(serverId);
   }
 });
+
+it("keeps a workspace whose archive is being undone when the host reports its removal", () => {
+  const serverId = "workspace-archive-undo";
+  const store = useSessionStore.getState();
+  store.initializeSession(serverId, null as unknown as DaemonClient);
+  const replica = new WorkspaceDirectoryReplica(serverId);
+  const restored = normalizeWorkspaceDescriptor(workspace("restored"));
+
+  const undo = markWorkspaceArchiveUndoPending({ serverId, workspaceId: restored.id });
+  try {
+    replica.acceptWorkspaces([restored]);
+
+    expect(replica.applyDelta({ kind: "remove", id: restored.id })).toEqual([]);
+    expect(useSessionStore.getState().sessions[serverId]?.workspaces.has(restored.id)).toBe(true);
+
+    settleWorkspaceArchiveIntent(undo);
+    replica.applyDelta({ kind: "remove", id: restored.id });
+    expect(useSessionStore.getState().sessions[serverId]?.workspaces.has(restored.id)).toBe(false);
+  } finally {
+    settleWorkspaceArchiveIntent(undo);
+    store.clearSession(serverId);
+  }
+});
+
+it("keeps a workspace whose archive is being undone when a refresh snapshot omits it", () => {
+  const serverId = "workspace-archive-undo-refresh";
+  const store = useSessionStore.getState();
+  store.initializeSession(serverId, null as unknown as DaemonClient);
+  const replica = new WorkspaceDirectoryReplica(serverId);
+  const restored = normalizeWorkspaceDescriptor(workspace("restored"));
+  const other = normalizeWorkspaceDescriptor(workspace("other"));
+  const workspaceIds = () => [
+    ...(useSessionStore.getState().sessions[serverId]?.workspaces.keys() ?? []),
+  ];
+
+  const undo = markWorkspaceArchiveUndoPending({ serverId, workspaceId: restored.id });
+  try {
+    replica.acceptWorkspaces([restored]);
+
+    replica.commitSnapshot({ workspaces: new Map([[other.id, other]]), projects: new Map() }, []);
+    expect(workspaceIds().sort()).toEqual(["other", "restored"]);
+
+    settleWorkspaceArchiveIntent(undo);
+    replica.commitSnapshot({ workspaces: new Map([[other.id, other]]), projects: new Map() }, []);
+    expect(workspaceIds()).toEqual(["other"]);
+  } finally {
+    settleWorkspaceArchiveIntent(undo);
+    store.clearSession(serverId);
+  }
+});
diff --git a/packages/app/src/runtime/directory-sync/workspace-replica.ts b/packages/app/src/runtime/directory-sync/workspace-replica.ts
index 8f21ebd214..b5a7895467 100644
--- a/packages/app/src/runtime/directory-sync/workspace-replica.ts
+++ b/packages/app/src/runtime/directory-sync/workspace-replica.ts
@@ -14,6 +14,7 @@ import { useWorkspaceSetupStore } from "@/stores/workspace-setup-store";
 import {
   clearWorkspaceArchivePending,
   shouldSuppressWorkspaceForLocalArchive,
+  shouldSuppressWorkspaceRemovalForLocalUndo,
 } from "@/contexts/session-workspace-upserts";
 import { resolveWorkspaceMapKeyByIdentity } from "@/utils/workspace-identity";
 import type { DirectoryReplicaMutation } from "@/runtime/replica-cache";
@@ -107,6 +108,15 @@ export class WorkspaceDirectoryReplica {
         workspaces.set(workspaceId, workspace);
       }
     }
+    // A snapshot taken while an undo runs can predate the restore; the host publishes the row.
+    for (const [workspaceId, workspace] of this.workspaces) {
+      if (
+        !workspaces.has(workspaceId) &&
+        shouldSuppressWorkspaceRemovalForLocalUndo({ serverId: this.serverId, workspaceId })
+      ) {
+        workspaces.set(workspaceId, workspace);
+      }
+    }
     for (const workspace of workspaces.values()) this.applySetupStatus(workspace);
     this.workspaces = workspaces;
     this.projects = new Map(snapshot.projects);
@@ -173,6 +183,12 @@ export class WorkspaceDirectoryReplica {
       kind: "remove";
     },
   ): DirectoryReplicaMutation[] {
+    // The archive this remove reports is being undone; the host publishes the restored row.
+    if (
+      shouldSuppressWorkspaceRemovalForLocalUndo({ serverId: this.serverId, workspaceId: delta.id })
+    ) {
+      return [];
+    }
     this.deleteWorkspace(delta.id);
     const mutations: DirectoryReplicaMutation[] = [
       { kind: "workspace", type: "delete", id: delta.id },
diff --git a/packages/app/src/screens/workspace/workspace-screen.tsx b/packages/app/src/screens/workspace/workspace-screen.tsx
index d30893078c..f4b131d041 100644
--- a/packages/app/src/screens/workspace/workspace-screen.tsx
+++ b/packages/app/src/screens/workspace/workspace-screen.tsx
@@ -137,6 +137,7 @@ import { useWorkspace } from "@/stores/session-store-hooks";
 import type { CheckoutStatusPayload } from "@/git/use-status-query";
 import { confirmDialog } from "@/utils/confirm-dialog";
 import { useArchiveAgent } from "@/hooks/use-archive-agent";
+import { useWorkspaceArchiveUndoRunning } from "@/workspace/archive-undo";
 import { useStableEvent } from "@/hooks/use-stable-event";
 import { removeResidentBrowserWebview } from "@/desktop/browser/resident-webviews";
 import { createWorkspaceBrowser, useBrowserStore } from "@/desktop/browser/store";
@@ -1249,6 +1250,11 @@ function WorkspaceScreenContent({
   const hasHydratedAgents = useSessionStore(
     (state) => state.sessions[normalizedServerId]?.hasHydratedAgents ?? false,
   );
+  // An undo puts the row back before the host restores its agents. Their tabs stay until it settles.
+  const isArchiveUndoRunning = useWorkspaceArchiveUndoRunning({
+    serverId: normalizedServerId,
+    workspaceId: normalizedWorkspaceId,
+  });
   const workspaceRouteState = useResolvedWorkspaceRouteState({
     serverId: normalizedServerId,
     workspace: workspaceDescriptor,
@@ -1549,7 +1555,7 @@ function WorkspaceScreenContent({
       persistenceKey,
       buildWorkspaceTabSnapshot({
         agentVisibility: workspaceAgentVisibility,
-        agentsHydrated: hasHydratedAgents,
+        agentsHydrated: hasHydratedAgents && !isArchiveUndoRunning,
         terminalsHydrated: terminalsQuery.isSuccess,
         knownTerminalIds,
         standaloneTerminalIds,
@@ -1560,6 +1566,7 @@ function WorkspaceScreenContent({
     );
   }, [
     hasHydratedAgents,
+    isArchiveUndoRunning,
     hasHydratedWorkspaceLayoutStore,
     pendingTerminalCreateInput,
     createTerminalMutation.isPending,
diff --git a/packages/app/src/workspace/archive-undo/index.ts b/packages/app/src/workspace/archive-undo/index.ts
new file mode 100644
index 0000000000..c6107367aa
--- /dev/null
+++ b/packages/app/src/workspace/archive-undo/index.ts
@@ -0,0 +1,8 @@
+export {
+  archiveWorkspaceWithUndo,
+  undoLatestWorkspaceArchive,
+  type UndoableWorkspaceArchiveClient,
+} from "./internal/undo-window";
+export { WorkspaceArchiveUndoShortcutHost } from "./internal/undo-shortcut-host";
+export { supportsWorkspaceArchiveUndo } from "./internal/capability";
+export { useWorkspaceArchiveUndoRunning } from "./internal/use-workspace-archive-undo-running";
diff --git a/packages/app/src/workspace/archive-undo/internal/capability.ts b/packages/app/src/workspace/archive-undo/internal/capability.ts
new file mode 100644
index 0000000000..5f5a4a7c20
--- /dev/null
+++ b/packages/app/src/workspace/archive-undo/internal/capability.ts
@@ -0,0 +1,8 @@
+import { useSessionStore } from "@/stores/session-store";
+
+export function supportsWorkspaceArchiveUndo(serverId: string): boolean {
+  return (
+    useSessionStore.getState().sessions[serverId]?.serverInfo?.features?.workspaceArchiveUndo ===
+    true
+  );
+}
diff --git a/packages/app/src/workspace/archive-undo/internal/undo-shortcut-host.tsx b/packages/app/src/workspace/archive-undo/internal/undo-shortcut-host.tsx
new file mode 100644
index 0000000000..3d2ea9c4e4
--- /dev/null
+++ b/packages/app/src/workspace/archive-undo/internal/undo-shortcut-host.tsx
@@ -0,0 +1,22 @@
+import { useKeyboardActionHandler } from "@/hooks/use-keyboard-action-handler";
+import type { KeyboardActionId } from "@/keyboard/keyboard-action-dispatcher";
+import { hasUndoableWorkspaceArchive, undoLatestWorkspaceArchive } from "./undo-window";
+
+const UNDO_ARCHIVE_ACTIONS: readonly KeyboardActionId[] = ["workspace.archive.undo"];
+
+/**
+ * Cmd/Ctrl+Z for the archive toast. Mounted once at the app root because the row that started
+ * the archive unmounts as soon as its workspace hides. It claims the key only while an archive
+ * can be undone, so the key falls through to text undo the rest of the time.
+ */
+export function WorkspaceArchiveUndoShortcutHost(): null {
+  useKeyboardActionHandler({
+    handlerId: "workspace-archive-undo-global",
+    actions: UNDO_ARCHIVE_ACTIONS,
+    enabled: true,
+    priority: 0,
+    isActive: hasUndoableWorkspaceArchive,
+    handle: undoLatestWorkspaceArchive,
+  });
+  return null;
+}
diff --git a/packages/app/src/workspace/archive-undo/internal/undo-window.test.ts b/packages/app/src/workspace/archive-undo/internal/undo-window.test.ts
new file mode 100644
index 0000000000..efa9a539ac
--- /dev/null
+++ b/packages/app/src/workspace/archive-undo/internal/undo-window.test.ts
@@ -0,0 +1,301 @@
+import type { DaemonClient } from "@getpaseo/client/internal/daemon-client";
+import type { ReactNode } from "react";
+import { afterEach, beforeEach, describe, expect, it } from "vitest";
+import type { ToastApi, ToastShowOptions } from "@/components/toast-host";
+import { clearWorkspaceArchivePending } from "@/contexts/session-workspace-upserts";
+import { getHostRuntimeStore } from "@/runtime/host-runtime";
+import { useSessionStore, type WorkspaceDescriptor } from "@/stores/session-store";
+import { seedSessionHosts } from "@/test/seed-session";
+import {
+  archiveWorkspaceWithUndo,
+  undoLatestWorkspaceArchive,
+  type UndoableWorkspaceArchiveClient,
+} from "@/workspace/archive-undo";
+
+const SERVER_ID = "workspace-archive-undo-window";
+
+interface Deferred<T> {
+  promise: Promise<T>;
+  resolve: (value: T) => void;
+  reject: (error: unknown) => void;
+}
+
+function deferred<T>(): Deferred<T> {
+  let resolve!: (value: T) => void;
+  let reject!: (error: unknown) => void;
+  const promise = new Promise<T>((res, rej) => {
+    resolve = res;
+    reject = rej;
+  });
+  return { promise, resolve, reject };
+}
+
+function workspace(id: string): WorkspaceDescriptor {
+  return {
+    createdAt: null,
+    lastUserMessageAt: null,
+    id,
+    projectId: "project",
+    projectDisplayName: "Project",
+    projectRootPath: "/repo/project",
+    workspaceDirectory: `/repo/project/${id}`,
+    projectKind: "git",
+    workspaceKind: "worktree",
+    name: id,
+    status: "done",
+    archivingAt: null,
+    statusEnteredAt: null,
+    diffStat: null,
+    scripts: [],
+  };
+}
+
+/** A toast host with one slot, like the app's: a new toast replaces the shown one. */
+function createToastHost() {
+  let shown: { content: ReactNode; options?: ToastShowOptions; dismiss: () => void } | null = null;
+  const errors: string[] = [];
+  const api: ToastApi = {
+    show: (content, options) => {
+      const previous = shown;
+      const entry = {
+        content,
+        options,
+        dismiss: () => {
+          if (shown !== entry) return;
+          shown = null;
+          options?.onDismiss?.();
+        },
+      };
+      shown = entry;
+      previous?.options?.onDismiss?.();
+      return entry.dismiss;
+    },
+    copied: () => {},
+    error: (message) => {
+      errors.push(message);
+      api.show(message);
+    },
+  };
+  return {
+    api,
+    errors,
+    get shownTestID() {
+      return shown?.options?.testID ?? null;
+    },
+    timeOut: () => shown?.dismiss(),
+  };
+}
+
+type ArchivePayload = Awaited<ReturnType<UndoableWorkspaceArchiveClient["archiveWorkspace"]>>;
+
+function createClient() {
+  const archives = new Map<string, Deferred<ArchivePayload>>();
+  const undos = new Map<string, Deferred<void>>();
+  const client: UndoableWorkspaceArchiveClient = {
+    archiveWorkspace: (workspaceId) => {
+      const response = deferred<ArchivePayload>();
+      archives.set(workspaceId, response);
+      return response.promise;
+    },
+    undoWorkspaceArchive: (workspaceId) => {
+      const response = deferred<void>();
+      undos.set(workspaceId, response);
+      return response.promise;
+    },
+  };
+  return {
+    client,
+    finishArchive: (workspaceId: string, payload: Partial<ArchivePayload> = {}) =>
+      archives.get(workspaceId)?.resolve({ error: null, ...payload }),
+    undoRequested: (workspaceId: string) => undos.has(workspaceId),
+    finishUndo: (workspaceId: string) => undos.get(workspaceId)?.resolve(),
+    failUndo: (workspaceId: string, error: Error) => undos.get(workspaceId)?.reject(error),
+  };
+}
+
+function storedWorkspace(id: string): WorkspaceDescriptor | undefined {
+  return useSessionStore.getState().sessions[SERVER_ID]?.workspaces.get(id);
+}
+
+function startArchive(input: {
+  host: ReturnType<typeof createClient>;
+  toast: ReturnType<typeof createToastHost>;
+  workspaceId: string;
+  committed: string[];
+}) {
+  return archiveWorkspaceWithUndo({
+    client: input.host.client,
+    workspace: { serverId: SERVER_ID, workspaceId: input.workspaceId },
+    toast: input.toast.api,
+    onArchiveCommitted: () => input.committed.push(input.workspaceId),
+  });
+}
+
+beforeEach(() => {
+  seedSessionHosts([SERVER_ID]);
+  useSessionStore.getState().initializeSession(SERVER_ID, {} as DaemonClient);
+  getHostRuntimeStore().acceptWorkspaceSnapshots(SERVER_ID, [workspace("a"), workspace("b")]);
+});
+
+afterEach(() => {
+  undoLatestWorkspaceArchive();
+  clearWorkspaceArchivePending({ serverId: SERVER_ID, workspaceId: "a" });
+  clearWorkspaceArchivePending({ serverId: SERVER_ID, workspaceId: "b" });
+  seedSessionHosts([]);
+  useSessionStore.setState((state) => ({ ...state, sessions: {} }));
+});
+
+describe("archiveWorkspaceWithUndo", () => {
+  it("commits the archive only once its toast is gone", async () => {
+    const host = createClient();
+    const toast = createToastHost();
+    const committed: string[] = [];
+
+    const archive = startArchive({ host, toast, workspaceId: "a", committed });
+    expect(toast.shownTestID).toBe("workspace-archived-toast");
+    host.finishArchive("a");
+    await archive;
+    expect(committed).toEqual([]);
+
+    toast.timeOut();
+    expect({ committed, undone: undoLatestWorkspaceArchive() }).toEqual({
+      committed: ["a"],
+      undone: false,
+    });
+  });
+
+  it("keeps the layout when another client restores the workspace before the toast closes", async () => {
+    const host = createClient();
+    const toast = createToastHost();
+    const committed: string[] = [];
+
+    const archive = startArchive({ host, toast, workspaceId: "a", committed });
+    host.finishArchive("a");
+    await archive;
+    clearWorkspaceArchivePending({ serverId: SERVER_ID, workspaceId: "a" });
+    getHostRuntimeStore().acceptWorkspaceSnapshots(SERVER_ID, [workspace("a")]);
+    toast.timeOut();
+
+    expect({ committed, row: storedWorkspace("a") }).toEqual({
+      committed: [],
+      row: workspace("a"),
+    });
+  });
+
+  it("commits when the archive finishes after its toast already timed out", async () => {
+    const host = createClient();
+    const toast = createToastHost();
+    const committed: string[] = [];
+
+    const archive = startArchive({ host, toast, workspaceId: "a", committed });
+    toast.timeOut();
+    expect(committed).toEqual([]);
+    host.finishArchive("a");
+    await archive;
+
+    expect(committed).toEqual(["a"]);
+  });
+
+  it("undo during a running archive brings the row back and never commits", async () => {
+    const host = createClient();
+    const toast = createToastHost();
+    const committed: string[] = [];
+
+    const archive = startArchive({ host, toast, workspaceId: "a", committed });
+    expect(storedWorkspace("a")).toBeUndefined();
+
+    expect(undoLatestWorkspaceArchive()).toBe(true);
+    expect({
+      row: storedWorkspace("a"),
+      undoRequested: host.undoRequested("a"),
+      toast: toast.shownTestID,
+    }).toEqual({ row: workspace("a"), undoRequested: true, toast: null });
+
+    host.finishArchive("a", { canceled: true, error: "Workspace archive was undone" });
+    await archive;
+    host.finishUndo("a");
+    toast.timeOut();
+
+    expect({ committed, errors: toast.errors, row: storedWorkspace("a") }).toEqual({
+      committed: [],
+      errors: [],
+      row: workspace("a"),
+    });
+  });
+
+  it("does not claim Cmd+Z when no archive can be undone", async () => {
+    const host = createClient();
+    const toast = createToastHost();
+
+    expect(undoLatestWorkspaceArchive()).toBe(false);
+
+    const archive = startArchive({ host, toast, workspaceId: "a", committed: [] });
+    host.finishArchive("a");
+    await archive;
+    toast.timeOut();
+
+    expect(undoLatestWorkspaceArchive()).toBe(false);
+    expect(host.undoRequested("a")).toBe(false);
+  });
+
+  it("a newer archive takes over undo and commits the older one", async () => {
+    const host = createClient();
+    const toast = createToastHost();
+    const committed: string[] = [];
+
+    const first = startArchive({ host, toast, workspaceId: "a", committed });
+    host.finishArchive("a");
+    await first;
+    const second = startArchive({ host, toast, workspaceId: "b", committed });
+    expect(committed).toEqual(["a"]);
+
+    expect(undoLatestWorkspaceArchive()).toBe(true);
+    expect({ undoA: host.undoRequested("a"), undoB: host.undoRequested("b") }).toEqual({
+      undoA: false,
+      undoB: true,
+    });
+    host.finishArchive("b", { canceled: true });
+    await second;
+  });
+
+  it("reports a failed undo and hides the row again", async () => {
+    const host = createClient();
+    const toast = createToastHost();
+
+    const archive = startArchive({ host, toast, workspaceId: "a", committed: [] });
+    host.finishArchive("a");
+    await archive;
+    undoLatestWorkspaceArchive();
+    host.failUndo("a", new Error("Branch is gone"));
+    await expect.poll(() => toast.errors).toEqual(["Couldn't undo the archive"]);
+
+    expect(storedWorkspace("a")).toBeUndefined();
+  });
+
+  it("stays quiet about an archive that failed after the user undid it", async () => {
+    const host = createClient();
+    const toast = createToastHost();
+
+    const archive = startArchive({ host, toast, workspaceId: "a", committed: [] });
+    undoLatestWorkspaceArchive();
+    host.finishArchive("a", { error: "registry unavailable" });
+
+    await expect(archive).resolves.toBeUndefined();
+    expect(toast.errors).toEqual([]);
+  });
+
+  it("rejects a failed archive, closes its toast and puts the row back", async () => {
+    const host = createClient();
+    const toast = createToastHost();
+
+    const archive = startArchive({ host, toast, workspaceId: "a", committed: [] });
+    host.finishArchive("a", { error: "registry unavailable" });
+
+    await expect(archive).rejects.toThrow("registry unavailable");
+    expect({
+      toast: toast.shownTestID,
+      undone: undoLatestWorkspaceArchive(),
+      row: storedWorkspace("a"),
+    }).toEqual({ toast: null, undone: false, row: workspace("a") });
+  });
+});
diff --git a/packages/app/src/workspace/archive-undo/internal/undo-window.tsx b/packages/app/src/workspace/archive-undo/internal/undo-window.tsx
new file mode 100644
index 0000000000..5dc968124e
--- /dev/null
+++ b/packages/app/src/workspace/archive-undo/internal/undo-window.tsx
@@ -0,0 +1,129 @@
+import type { DismissToast, ToastApi } from "@/components/toast-host";
+import { i18n } from "@/i18n/i18next";
+import type { WorkspaceDescriptor } from "@/stores/session-store";
+import {
+  beginOptimisticWorkspaceArchive,
+  isWorkspaceListed,
+  undoWorkspaceArchiveOptimistically,
+  type WorkspaceArchiveTarget,
+} from "@/workspace/workspace-archive";
+import { WorkspaceArchivedToast } from "./workspace-archived-toast";
+
+/** How long the archived toast, and with it the chance to undo, stays up. */
+export const WORKSPACE_ARCHIVE_UNDO_WINDOW_MS = 6000;
+
+export interface UndoableWorkspaceArchiveClient {
+  archiveWorkspace: (workspaceId: string) => Promise<{ error: string | null; canceled?: boolean }>;
+  undoWorkspaceArchive: (workspaceId: string) => Promise<void>;
+}
+
+interface UndoWindowInput {
+  client: UndoableWorkspaceArchiveClient;
+  workspace: WorkspaceArchiveTarget;
+  toast: ToastApi;
+  hidden: WorkspaceDescriptor | null;
+  onArchiveCommitted: () => void;
+}
+
+let latest: UndoWindow | null = null;
+
+/**
+ * One archive's chance to be undone. It opens when the row hides and closes when its toast
+ * leaves the screen (timeout, replaced by another toast, or undo).
+ *
+ * - `open`: undo is offered.
+ * - `closed`: undo is no longer offered; the archive stands.
+ * - `undone`: the user took the archive back.
+ */
+class UndoWindow {
+  phase: "open" | "closed" | "undone" = "open";
+  private archived = false;
+  private readonly dismissToast: DismissToast;
+
+  constructor(private readonly input: UndoWindowInput) {
+    this.dismissToast = input.toast.show(<WorkspaceArchivedToast onUndo={this.undo} />, {
+      durationMs: WORKSPACE_ARCHIVE_UNDO_WINDOW_MS,
+      testID: "workspace-archived-toast",
+      onDismiss: this.close,
+    });
+  }
+
+  /** The host finished the archive. It commits now if undo is no longer offered. */
+  archiveFinished(): void {
+    this.archived = true;
+    if (this.phase === "closed") this.commit();
+  }
+
+  /** The archive failed on the host, so there is nothing left to undo. */
+  archiveFailed(): void {
+    this.close();
+    this.dismissToast();
+  }
+
+  readonly close = (): void => {
+    if (this.phase !== "open") return;
+    this.phase = "closed";
+    this.release();
+    if (this.archived) this.commit();
+  };
+
+  /** Commits unless the workspace is back by now, for example restored from another client. */
+  private commit(): void {
+    if (isWorkspaceListed(this.input.workspace)) return;
+    this.input.onArchiveCommitted();
+  }
+
+  readonly undo = (): boolean => {
+    if (this.phase !== "open") return false;
+    this.phase = "undone";
+    this.release();
+    this.dismissToast();
+    void undoWorkspaceArchiveOptimistically(this.input).catch((error: unknown) => {
+      console.warn("[workspace-archive-undo] undo failed", error);
+      this.input.toast.error(i18n.t("sidebar.workspace.toasts.undoArchiveFailed"));
+    });
+    return true;
+  };
+
+  private release(): void {
+    if (latest === this) latest = null;
+  }
+}
+
+/**
+ * Archives a workspace and offers to undo it until the toast goes away.
+ *
+ * `onArchiveCommitted` runs once the archive both finished on the host and can no longer be
+ * undone, and only if the workspace is still gone then. Local state the undo would want back
+ * (tabs, layout) survives the window, and survives a restore from another client.
+ * Rejects when the archive fails and was not undone; the row is back by then.
+ */
+export async function archiveWorkspaceWithUndo(input: {
+  client: UndoableWorkspaceArchiveClient;
+  workspace: WorkspaceArchiveTarget;
+  toast: ToastApi;
+  onArchiveCommitted: () => void;
+}): Promise<void> {
+  const archive = beginOptimisticWorkspaceArchive(input);
+  const window = new UndoWindow({ ...input, hidden: archive.hidden });
+  latest = window;
+
+  let outcome: Awaited<typeof archive.done>;
+  try {
+    outcome = await archive.done;
+  } catch (error) {
+    if (window.phase === "undone") return;
+    window.archiveFailed();
+    throw error;
+  }
+  if (outcome === "archived") window.archiveFinished();
+}
+
+/** Undoes the most recent archive while its toast is up. Returns false when there is none. */
+export function undoLatestWorkspaceArchive(): boolean {
+  return latest ? latest.undo() : false;
+}
+
+export function hasUndoableWorkspaceArchive(): boolean {
+  return latest !== null;
+}
diff --git a/packages/app/src/workspace/archive-undo/internal/use-workspace-archive-undo-running.ts b/packages/app/src/workspace/archive-undo/internal/use-workspace-archive-undo-running.ts
new file mode 100644
index 0000000000..31e9dd54fd
--- /dev/null
+++ b/packages/app/src/workspace/archive-undo/internal/use-workspace-archive-undo-running.ts
@@ -0,0 +1,21 @@
+import { useCallback, useSyncExternalStore } from "react";
+import {
+  isWorkspaceArchiveUndoPending,
+  subscribeWorkspaceArchiveIntents,
+} from "@/contexts/session-workspace-upserts";
+
+/**
+ * True while this client's undo of the workspace's archive is running on the host. Until it
+ * settles, the workspace's agents may still read as archived even though they are coming back.
+ */
+export function useWorkspaceArchiveUndoRunning(input: {
+  serverId: string;
+  workspaceId: string | null;
+}): boolean {
+  const { serverId, workspaceId } = input;
+  const read = useCallback(
+    () => isWorkspaceArchiveUndoPending({ serverId, workspaceId }),
+    [serverId, workspaceId],
+  );
+  return useSyncExternalStore(subscribeWorkspaceArchiveIntents, read, read);
+}
diff --git a/packages/app/src/workspace/archive-undo/internal/workspace-archived-toast.tsx b/packages/app/src/workspace/archive-undo/internal/workspace-archived-toast.tsx
new file mode 100644
index 0000000000..584b71dec9
--- /dev/null
+++ b/packages/app/src/workspace/archive-undo/internal/workspace-archived-toast.tsx
@@ -0,0 +1,41 @@
+import { useMemo } from "react";
+import { useTranslation } from "react-i18next";
+import { Text, View } from "react-native";
+import { StyleSheet } from "react-native-unistyles";
+import { Button } from "@/components/ui/button";
+import { Shortcut } from "@/components/ui/shortcut";
+import { useShortcutKeys } from "@/hooks/use-shortcut-keys";
+
+export function WorkspaceArchivedToast({ onUndo }: { onUndo: () => void }) {
+  const { t } = useTranslation();
+  const undoKeys = useShortcutKeys("undo-archive-workspace");
+  const undoShortcut = useMemo(() => (undoKeys ? <Shortcut chord={undoKeys} /> : null), [undoKeys]);
+
+  return (
+    <View style={styles.row}>
+      <Text style={styles.message}>{t("sidebar.workspace.toasts.archived")}</Text>
+      <Button
+        size="sm"
+        onPress={onUndo}
+        testID="workspace-archived-toast-undo"
+        trailing={undoShortcut}
+      >
+        {t("sidebar.workspace.toasts.undoArchive")}
+      </Button>
+    </View>
+  );
+}
+
+const styles = StyleSheet.create((theme) => ({
+  row: {
+    flexDirection: "row",
+    alignItems: "center",
+    gap: theme.spacing[2],
+  },
+  message: {
+    flexShrink: 1,
+    color: theme.colors.foreground,
+    fontSize: theme.fontSize.base,
+    fontWeight: theme.fontWeight.normal,
+  },
+}));
diff --git a/packages/app/src/workspace/use-workspace-archive.ts b/packages/app/src/workspace/use-workspace-archive.ts
index 7dc86a61ae..9608cef0cd 100644
--- a/packages/app/src/workspace/use-workspace-archive.ts
+++ b/packages/app/src/workspace/use-workspace-archive.ts
@@ -10,6 +10,7 @@ import {
 import type { WorkspaceDescriptor } from "@/stores/session-store";
 import { useWorkspaceLayoutStore } from "@/stores/workspace-layout-store";
 import { buildWorkspaceTabPersistenceKey } from "@/workspace-tabs/model";
+import { archiveWorkspaceWithUndo, supportsWorkspaceArchiveUndo } from "@/workspace/archive-undo";
 import { archiveWorkspaceOptimistically } from "@/workspace/workspace-archive";
 
 function purgeArchivedWorkspaceState(input: { serverId: string; workspaceId: string }): void {
@@ -58,17 +59,22 @@ export function useWorkspaceArchive(input: ArchiveWorkspaceInput): WorkspaceArch
       toast.error(t("sidebar.workspace.toasts.hostDisconnected"));
       return;
     }
+    const workspace = { serverId, workspaceId };
     onSetHiding?.(true);
     try {
       onArchiveStarted();
-      await archiveWorkspaceOptimistically({
-        client,
-        workspace: {
-          serverId,
-          workspaceId,
-        },
-      });
-      purgeArchivedWorkspaceState({ serverId, workspaceId });
+      if (supportsWorkspaceArchiveUndo(serverId)) {
+        await archiveWorkspaceWithUndo({
+          client,
+          workspace,
+          toast,
+          onArchiveCommitted: () => purgeArchivedWorkspaceState(workspace),
+        });
+      } else {
+        // COMPAT(workspaceArchiveUndo): hosts before v0.15.3 cannot undo; remove after 2027-05-06.
+        await archiveWorkspaceOptimistically({ client, workspace });
+        purgeArchivedWorkspaceState(workspace);
+      }
     } catch (error) {
       toast.error(
         error instanceof Error ? error.message : t("sidebar.workspace.toasts.archiveFailed"),
diff --git a/packages/app/src/workspace/workspace-archive.test.ts b/packages/app/src/workspace/workspace-archive.test.ts
index 3facdee34e..e519bcffb3 100644
--- a/packages/app/src/workspace/workspace-archive.test.ts
+++ b/packages/app/src/workspace/workspace-archive.test.ts
@@ -5,11 +5,14 @@ import { afterEach, beforeEach, describe, expect, it, vi } from "vitest";
 import {
   clearWorkspaceArchivePending,
   isWorkspaceArchivePending,
+  isWorkspaceArchiveUndoPending,
 } from "@/contexts/session-workspace-upserts";
 import { useSessionStore, type WorkspaceDescriptor } from "@/stores/session-store";
 import {
   archiveWorkspaceOptimistically,
   archiveWorkspacesOptimistically,
+  beginOptimisticWorkspaceArchive,
+  undoWorkspaceArchiveOptimistically,
   type WorkspaceArchiveTarget,
 } from "@/workspace/workspace-archive";
 
@@ -21,12 +24,14 @@ type ArchiveWorkspacePayload = Awaited<ReturnType<DaemonClient["archiveWorkspace
 function archivePayload(input: {
   workspaceId: string;
   error?: string | null;
+  canceled?: boolean;
 }): ArchiveWorkspacePayload {
   return {
     requestId: "request",
     workspaceId: input.workspaceId,
     archivedAt: null,
     error: input.error ?? null,
+    ...(input.canceled ? { canceled: true } : {}),
   };
 }
 
@@ -224,3 +229,140 @@ describe("archiveWorkspacesOptimistically", () => {
     expect(storedWorkspaceOn(SECOND_SERVER_ID, second.id)).toBeUndefined();
   });
 });
+
+describe("undoWorkspaceArchiveOptimistically", () => {
+  it("brings the row back while the host undoes the archive it is still running", async () => {
+    const archived = workspace();
+    getHostRuntimeStore().acceptWorkspaceSnapshots(SERVER_ID, [archived]);
+    const archiveResponse = deferred<ArchiveWorkspacePayload>();
+    const undoResponse = deferred<void>();
+    const archive = beginOptimisticWorkspaceArchive({
+      client: createClient(async () => archiveResponse.promise),
+      workspace: target(),
+    });
+
+    const undo = undoWorkspaceArchiveOptimistically({
+      client: { undoWorkspaceArchive: async () => undoResponse.promise },
+      workspace: target(),
+      hidden: archive.hidden,
+    });
+    expect(storedWorkspace(archived.id)).toEqual(archived);
+
+    // The host answers the canceled archive before the undo.
+    archiveResponse.resolve(archivePayload({ workspaceId: archived.id, canceled: true }));
+    await expect(archive.done).resolves.toBe("canceled");
+    undoResponse.resolve();
+    await undo;
+
+    expect({
+      row: storedWorkspace(archived.id),
+      archivePending: isWorkspaceArchivePending(target()),
+      undoPending: isWorkspaceArchiveUndoPending(target()),
+    }).toEqual({ row: archived, archivePending: false, undoPending: false });
+  });
+
+  it("hides the row again when the host cannot undo the archive", async () => {
+    const archived = workspace();
+    getHostRuntimeStore().acceptWorkspaceSnapshots(SERVER_ID, [archived]);
+    const archive = beginOptimisticWorkspaceArchive({
+      client: createClient(async () => archivePayload({ workspaceId: archived.id })),
+      workspace: target(),
+    });
+    await archive.done;
+
+    await expect(
+      undoWorkspaceArchiveOptimistically({
+        client: {
+          undoWorkspaceArchive: async () => {
+            throw new Error("Branch is gone");
+          },
+        },
+        workspace: target(),
+        hidden: archive.hidden,
+      }),
+    ).rejects.toThrow("Branch is gone");
+
+    expect(storedWorkspace(archived.id)).toBeUndefined();
+    expect(isWorkspaceArchiveUndoPending(target())).toBe(false);
+  });
+
+  it("leaves a re-archived row hidden when the earlier undo settles", async () => {
+    const archived = workspace();
+    getHostRuntimeStore().acceptWorkspaceSnapshots(SERVER_ID, [archived]);
+    const undoResponse = deferred<void>();
+    const first = beginOptimisticWorkspaceArchive({
+      client: createClient(async () => archivePayload({ workspaceId: archived.id })),
+      workspace: target(),
+    });
+    await first.done;
+    const undo = undoWorkspaceArchiveOptimistically({
+      client: { undoWorkspaceArchive: async () => undoResponse.promise },
+      workspace: target(),
+      hidden: first.hidden,
+    });
+
+    const rearchive = beginOptimisticWorkspaceArchive({
+      client: createClient(async () => new Promise<ArchiveWorkspacePayload>(() => {})),
+      workspace: target(),
+    });
+    undoResponse.resolve();
+    await undo;
+
+    expect(rearchive.hidden).toEqual(archived);
+    expect(storedWorkspace(archived.id)).toBeUndefined();
+    expect(isWorkspaceArchivePending(target())).toBe(true);
+  });
+  it("puts the row back when another client's undo cancels this archive", async () => {
+    const archived = workspace();
+    getHostRuntimeStore().acceptWorkspaceSnapshots(SERVER_ID, [archived]);
+    const archive = beginOptimisticWorkspaceArchive({
+      client: createClient(async () =>
+        archivePayload({ workspaceId: archived.id, canceled: true, error: "undone" }),
+      ),
+      workspace: target(),
+    });
+
+    await expect(archive.done).resolves.toBe("canceled");
+
+    expect({
+      row: storedWorkspace(archived.id),
+      archivePending: isWorkspaceArchivePending(target()),
+    }).toEqual({ row: archived, archivePending: false });
+  });
+
+  it("an earlier undo settling keeps holding the row for a later undo", async () => {
+    const archived = workspace();
+    getHostRuntimeStore().acceptWorkspaceSnapshots(SERVER_ID, [archived]);
+    const firstUndoResponse = deferred<void>();
+    const secondUndoResponse = deferred<void>();
+    const first = beginOptimisticWorkspaceArchive({
+      client: createClient(async () => archivePayload({ workspaceId: archived.id })),
+      workspace: target(),
+    });
+    await first.done;
+    const firstUndo = undoWorkspaceArchiveOptimistically({
+      client: { undoWorkspaceArchive: async () => firstUndoResponse.promise },
+      workspace: target(),
+      hidden: first.hidden,
+    });
+    const second = beginOptimisticWorkspaceArchive({
+      client: createClient(async () => new Promise<ArchiveWorkspacePayload>(() => {})),
+      workspace: target(),
+    });
+    const secondUndo = undoWorkspaceArchiveOptimistically({
+      client: { undoWorkspaceArchive: async () => secondUndoResponse.promise },
+      workspace: target(),
+      hidden: second.hidden,
+    });
+
+    firstUndoResponse.resolve();
+    await firstUndo;
+
+    expect({
+      row: storedWorkspace(archived.id),
+      undoPending: isWorkspaceArchiveUndoPending(target()),
+    }).toEqual({ row: archived, undoPending: true });
+    secondUndoResponse.resolve();
+    await secondUndo;
+  });
+});
diff --git a/packages/app/src/workspace/workspace-archive.ts b/packages/app/src/workspace/workspace-archive.ts
index a4e5a00e80..fd757934ef 100644
--- a/packages/app/src/workspace/workspace-archive.ts
+++ b/packages/app/src/workspace/workspace-archive.ts
@@ -1,7 +1,10 @@
 import { getHostRuntimeStore } from "@/runtime/host-runtime";
 import {
-  clearWorkspaceArchivePending,
+  isWorkspaceArchiveIntentCurrent,
   markWorkspaceArchivePending,
+  markWorkspaceArchiveUndoPending,
+  settleWorkspaceArchiveIntent,
+  type WorkspaceArchiveIntent,
 } from "@/contexts/session-workspace-upserts";
 import { useSessionStore, type WorkspaceDescriptor } from "@/stores/session-store";
 import { resolveWorkspaceMapKeyByIdentity } from "@/utils/workspace-identity";
@@ -13,11 +16,25 @@ export interface WorkspaceArchiveTarget {
 }
 
 interface WorkspaceArchiveClient {
-  archiveWorkspace: (workspaceId: string) => Promise<{ error: string | null }>;
+  archiveWorkspace: (workspaceId: string) => Promise<{ error: string | null; canceled?: boolean }>;
+}
+
+interface WorkspaceArchiveUndoClient {
+  undoWorkspaceArchive: (workspaceId: string) => Promise<void>;
+}
+
+/** `canceled`: an undo stopped the archive on the host before it finished. */
+export type WorkspaceArchiveOutcome = "archived" | "canceled";
+
+export interface OptimisticWorkspaceArchive {
+  /** The row as it was before the archive hid it, for undo to put back. */
+  hidden: WorkspaceDescriptor | null;
+  done: Promise<WorkspaceArchiveOutcome>;
 }
 
 interface OptimisticWorkspaceArchiveSnapshot {
   workspace: WorkspaceDescriptor | null;
+  intent: WorkspaceArchiveIntent;
 }
 
 export interface WorkspaceArchiveFailure {
@@ -38,32 +55,42 @@ function isWorkspaceArchiveFailure(error: unknown): error is WorkspaceArchiveFai
   );
 }
 
-function hideWorkspaceOptimistically(
-  workspace: WorkspaceArchiveTarget,
-): OptimisticWorkspaceArchiveSnapshot {
+function findListedWorkspace(workspace: WorkspaceArchiveTarget): WorkspaceDescriptor | null {
   const workspaces = useSessionStore.getState().sessions[workspace.serverId]?.workspaces;
   const workspaceKey = resolveWorkspaceMapKeyByIdentity({
     workspaces,
     workspaceId: workspace.workspaceId,
   });
-  const snapshot = workspaceKey ? (workspaces?.get(workspaceKey) ?? null) : null;
-  markWorkspaceArchivePending({
+  return workspaceKey ? (workspaces?.get(workspaceKey) ?? null) : null;
+}
+
+/** True when the workspace is in this client's list, for example after another client restored it. */
+export function isWorkspaceListed(workspace: WorkspaceArchiveTarget): boolean {
+  return findListedWorkspace(workspace) !== null;
+}
+
+function hideWorkspaceOptimistically(
+  workspace: WorkspaceArchiveTarget,
+): OptimisticWorkspaceArchiveSnapshot {
+  const snapshot = findListedWorkspace(workspace);
+  const intent = markWorkspaceArchivePending({
     serverId: workspace.serverId,
     workspaceId: workspace.workspaceId,
   });
   getHostRuntimeStore().removeWorkspaceSnapshot(workspace.serverId, workspace.workspaceId);
-  return { workspace: snapshot };
+  return { workspace: snapshot, intent };
 }
 
+/**
+ * Puts back a row whose archive did not happen. Skipped when a newer request on this client
+ * (an undo, or another archive) owns the row by now.
+ */
 function restoreOptimisticallyHiddenWorkspace(input: {
   serverId: string;
-  workspaceId: string;
   snapshot: OptimisticWorkspaceArchiveSnapshot;
 }): void {
-  clearWorkspaceArchivePending({
-    serverId: input.serverId,
-    workspaceId: input.workspaceId,
-  });
+  if (!isWorkspaceArchiveIntentCurrent(input.snapshot.intent)) return;
+  settleWorkspaceArchiveIntent(input.snapshot.intent);
   if (input.snapshot.workspace) {
     getHostRuntimeStore().acceptWorkspaceSnapshots(input.serverId, [input.snapshot.workspace]);
   }
@@ -72,31 +99,75 @@ function restoreOptimisticallyHiddenWorkspace(input: {
 async function archiveWorkspaceOrThrow(input: {
   client: WorkspaceArchiveClient;
   workspaceId: string;
-}): Promise<void> {
+}): Promise<WorkspaceArchiveOutcome> {
   const payload = await input.client.archiveWorkspace(input.workspaceId);
+  if (payload.canceled) {
+    return "canceled";
+  }
   if (payload.error) {
     throw new Error(payload.error);
   }
+  return "archived";
+}
+
+/**
+ * Hides the row now and archives it on the host. A failed archive puts the row back, and so
+ * does a canceled one: an undo from another client stopped it, so the workspace stays.
+ */
+export function beginOptimisticWorkspaceArchive(input: {
+  client: WorkspaceArchiveClient;
+  workspace: WorkspaceArchiveTarget;
+}): OptimisticWorkspaceArchive {
+  const snapshot = hideWorkspaceOptimistically(input.workspace);
+  const done = (async () => {
+    try {
+      const outcome = await archiveWorkspaceOrThrow({
+        client: input.client,
+        workspaceId: input.workspace.workspaceId,
+      });
+      if (outcome === "canceled") {
+        restoreOptimisticallyHiddenWorkspace({ serverId: input.workspace.serverId, snapshot });
+      }
+      return outcome;
+    } catch (error) {
+      restoreOptimisticallyHiddenWorkspace({ serverId: input.workspace.serverId, snapshot });
+      throw error;
+    }
+  })();
+  return { hidden: snapshot.workspace, done };
 }
 
 export async function archiveWorkspaceOptimistically(input: {
   client: WorkspaceArchiveClient;
   workspace: WorkspaceArchiveTarget;
-}): Promise<void> {
-  const snapshot = hideWorkspaceOptimistically(input.workspace);
+}): Promise<WorkspaceArchiveOutcome> {
+  return beginOptimisticWorkspaceArchive(input).done;
+}
 
+/**
+ * Puts the archived row back now and asks the host to undo the archive, whether it is still
+ * running or already finished. A failed undo hides the row again, unless the user archived
+ * it again in the meantime.
+ */
+export async function undoWorkspaceArchiveOptimistically(input: {
+  client: WorkspaceArchiveUndoClient;
+  workspace: WorkspaceArchiveTarget;
+  hidden: WorkspaceDescriptor | null;
+}): Promise<void> {
+  const { serverId, workspaceId } = input.workspace;
+  const intent = markWorkspaceArchiveUndoPending({ serverId, workspaceId });
+  if (input.hidden) {
+    getHostRuntimeStore().acceptWorkspaceSnapshots(serverId, [input.hidden]);
+  }
   try {
-    await archiveWorkspaceOrThrow({
-      client: input.client,
-      workspaceId: input.workspace.workspaceId,
-    });
+    await input.client.undoWorkspaceArchive(workspaceId);
   } catch (error) {
-    restoreOptimisticallyHiddenWorkspace({
-      serverId: input.workspace.serverId,
-      workspaceId: input.workspace.workspaceId,
-      snapshot,
-    });
+    if (isWorkspaceArchiveIntentCurrent(intent)) {
+      getHostRuntimeStore().removeWorkspaceSnapshot(serverId, workspaceId);
+    }
     throw error;
+  } finally {
+    settleWorkspaceArchiveIntent(intent);
   }
 }
 
diff --git a/packages/client/src/daemon-client.ts b/packages/client/src/daemon-client.ts
index b29a34111c..7b235040bf 100644
--- a/packages/client/src/daemon-client.ts
+++ b/packages/client/src/daemon-client.ts
@@ -3628,6 +3628,23 @@ export class DaemonClient {
     }
   }
 
+  /** Rejects when the host could not put the workspace back; an old host has no such RPC. */
+  async undoWorkspaceArchive(workspaceId: string, requestId?: string): Promise<void> {
+    const payload =
+      await this.sendNamespacedCorrelatedSessionRequest<"workspace.archive.undo.response">({
+        requestId,
+        message: {
+          type: "workspace.archive.undo.request",
+          workspaceId,
+        },
+        // Undoing a finished worktree archive recreates the worktree, like recovery does.
+        timeout: 150_000,
+      });
+    if (!payload.accepted) {
+      throw new Error(payload.error ?? "The host could not undo the workspace archive");
+    }
+  }
+
   async resumeAgent(
     handle: AgentPersistenceHandle,
     overrides?: Partial<AgentSessionConfig>,
diff --git a/packages/protocol/src/messages.ts b/packages/protocol/src/messages.ts
index 5436e1737d..c5fc881240 100644
--- a/packages/protocol/src/messages.ts
+++ b/packages/protocol/src/messages.ts
@@ -1105,6 +1105,14 @@ export const WorkspaceRecoveryRestoreRequestSchema = z.object({
   requestId: z.string(),
 });
 
+// Undoes the latest archive of a workspace: cancels it if it is still running, otherwise
+// restores the workspace, then unarchives the agents that archive took down.
+export const WorkspaceArchiveUndoRequestSchema = z.object({
+  type: z.literal("workspace.archive.undo.request"),
+  workspaceId: z.string(),
+  requestId: z.string(),
+});
+
 export const SetVoiceModeMessageSchema = z.object({
   type: z.literal("set_voice_mode"),
   enabled: z.boolean(),
@@ -2249,6 +2257,16 @@ export const WorkspaceRecoveryRestoreResponseSchema = z.object({
   }),
 });
 
+export const WorkspaceArchiveUndoResponseSchema = z.object({
+  type: z.literal("workspace.archive.undo.response"),
+  payload: z.object({
+    requestId: z.string(),
+    workspaceId: z.string(),
+    accepted: z.boolean(),
+    error: z.string().nullable(),
+  }),
+});
+
 export const SetVoiceModeResponseMessageSchema = z.object({
   type: z.literal("set_voice_mode_response"),
   payload: z.object({
@@ -3355,6 +3373,7 @@ export const SessionInboundMessageSchema = z.discriminatedUnion("type", [
   WorkspaceLabelDeleteInspectRequestSchema,
   WorkspaceRecoveryInspectRequestSchema,
   WorkspaceRecoveryRestoreRequestSchema,
+  WorkspaceArchiveUndoRequestSchema,
   SetVoiceModeMessageSchema,
   SendAgentMessageRequestSchema,
   WaitForFinishRequestSchema,
@@ -3820,6 +3839,8 @@ export const ServerInfoStatusPayloadSchema = z
         worktreeRestore: z.boolean().optional(),
         // COMPAT(workspaceRecovery): added in v0.1.105, remove after 2027-01-11 once daemon floor >= v0.1.105.
         workspaceRecovery: z.boolean().optional(),
+        // COMPAT(workspaceArchiveUndo): added in v0.15.3, remove gate after 2027-05-06.
+        workspaceArchiveUndo: z.boolean().optional(),
         // COMPAT(workspaceFileEditing): added in v0.2.0, remove after 2027-01-18 once daemon floor >= v0.2.0.
         workspaceFileEditing: z.boolean().optional(),
         // COMPAT(fileByteWrites): added in v0.13.0, remove gate after 2027-04-20.
@@ -4796,6 +4817,8 @@ export const ArchiveWorkspaceResponseMessageSchema = z.object({
     workspaceId: z.string(),
     archivedAt: z.string().nullable(),
     error: z.string().nullable(),
+    // An undo stopped this archive before it finished; `error` carries the reason.
+    canceled: z.boolean().optional(),
   }),
 });
 
@@ -7231,6 +7254,7 @@ export const SessionOutboundMessageSchema = z.discriminatedUnion("type", [
   WorkspaceBaseBranchSetResponseSchema,
   WorkspaceRecoveryInspectResponseSchema,
   WorkspaceRecoveryRestoreResponseSchema,
+  WorkspaceArchiveUndoResponseSchema,
   WaitForFinishResponseMessageSchema,
   AgentPermissionRequestMessageSchema,
   AgentPermissionResolvedMessageSchema,
@@ -7444,6 +7468,7 @@ export type WorkspaceRecoveryInspectResponse = z.infer<
 export type WorkspaceRecoveryRestoreResponse = z.infer<
   typeof WorkspaceRecoveryRestoreResponseSchema
 >;
+export type WorkspaceArchiveUndoResponse = z.infer<typeof WorkspaceArchiveUndoResponseSchema>;
 export type WorkspaceCreateRequest = z.infer<typeof WorkspaceCreateRequestSchema>;
 export type WorkspaceCreateResponse = z.infer<typeof WorkspaceCreateResponseSchema>;
 export type ProjectRenameResponsePayload = z.infer<typeof ProjectRenameResponsePayloadSchema>;
@@ -7593,6 +7618,7 @@ export type WorkspacePinSetRequest = z.infer<typeof WorkspacePinSetRequestSchema
 export type WorkspaceBaseBranchSetRequest = z.infer<typeof WorkspaceBaseBranchSetRequestSchema>;
 export type WorkspaceRecoveryInspectRequest = z.infer<typeof WorkspaceRecoveryInspectRequestSchema>;
 export type WorkspaceRecoveryRestoreRequest = z.infer<typeof WorkspaceRecoveryRestoreRequestSchema>;
+export type WorkspaceArchiveUndoRequest = z.infer<typeof WorkspaceArchiveUndoRequestSchema>;
 export type SetAgentModeRequestMessage = z.infer<typeof SetAgentModeRequestMessageSchema>;
 export type SetAgentModelRequestMessage = z.infer<typeof SetAgentModelRequestMessageSchema>;
 export type SetAgentThinkingRequestMessage = z.infer<typeof SetAgentThinkingRequestMessageSchema>;
diff --git a/packages/server/src/server/agent/agent-manager.ts b/packages/server/src/server/agent/agent-manager.ts
index 9f87600ed9..81b5495377 100644
--- a/packages/server/src/server/agent/agent-manager.ts
+++ b/packages/server/src/server/agent/agent-manager.ts
@@ -2543,16 +2543,20 @@ export class AgentManager {
     if (this.agents.has(agentId)) await this.closeAgentRuntime(agentId);
     await this.syncNativeArchiveState(record.provider, record.persistence, "restore");
 
-    await registry.upsert({
+    const nextRecord: StoredAgentRecord = {
       ...record,
       ...(updates?.workspaceId ? { workspaceId: updates.workspaceId } : {}),
       ...(updates?.labels ? { labels: applyLabelPatch(record.labels, updates.labels) } : {}),
       archivedAt: null,
       updatedAt: new Date().toISOString(),
-    });
+    };
+    await registry.upsert(nextRecord);
 
     if (this.getAgent(agentId)) {
       this.notifyAgentState(agentId);
+    } else if (!nextRecord.internal) {
+      // Same publication archiveSnapshot makes, so a stored-only agent reappears for every client.
+      this.dispatchStoredAgentState(nextRecord);
     }
     return true;
   }
diff --git a/packages/server/src/server/authorization/operation-permissions.ts b/packages/server/src/server/authorization/operation-permissions.ts
index 8cc9d6d1a0..c45d9a5c32 100644
--- a/packages/server/src/server/authorization/operation-permissions.ts
+++ b/packages/server/src/server/authorization/operation-permissions.ts
@@ -219,6 +219,7 @@ const INBOUND_PERMISSION = {
   "workspace.base_branch.set.request": "workspace.write",
   "workspace.recovery.inspect.request": ["workspace.read", "hub.execute"],
   "workspace.recovery.restore.request": ["workspace.manage", "hub.execute"],
+  "workspace.archive.undo.request": ["workspace.manage", "hub.execute"],
   "workspace.script.list.request": "workspace.read",
   "workspace.script.start.request": "workspace.write",
   "workspace.script.stop.request": "workspace.write",
@@ -462,6 +463,7 @@ const OUTBOUND_PERMISSION = {
   "workspace.base_branch.set.response": "workspace.write",
   "workspace.recovery.inspect.response": ["workspace.read", "hub.execute"],
   "workspace.recovery.restore.response": ["workspace.manage", "hub.execute"],
+  "workspace.archive.undo.response": ["workspace.manage", "hub.execute"],
   "workspace.script.list.response": "workspace.read",
   "workspace.script.start.response": "workspace.write",
   "workspace.script.stop.response": "workspace.write",
diff --git a/packages/server/src/server/session.ts b/packages/server/src/server/session.ts
index 339a7c17fb..c652f70908 100644
--- a/packages/server/src/server/session.ts
+++ b/packages/server/src/server/session.ts
@@ -278,6 +278,10 @@ import {
   handleWorkspaceSetupRunRequest as handleWorkspaceSetupRunRequestMessage,
 } from "./worktree-session.js";
 import { archiveByScope, type ActiveWorkspaceRef } from "./workspace-archive-service.js";
+import {
+  WorkspaceArchiveOperations,
+  type WorkspaceArchiveUndoInput,
+} from "./workspace-archive-operations.js";
 import { WorkspaceSetupRuntime } from "./workspace-setup-runtime.js";
 import { SessionAuthorization, type DaemonPermission } from "./authorization/index.js";
 
@@ -286,6 +290,12 @@ function resolveWorkspaceSetupRuntime(
 ): WorkspaceSetupRuntime {
   return runtime ?? new WorkspaceSetupRuntime();
 }
+
+function resolveWorkspaceArchiveOperations(
+  operations: WorkspaceArchiveOperations | undefined,
+): WorkspaceArchiveOperations {
+  return operations ?? new WorkspaceArchiveOperations();
+}
 import { WorktreeRequestError, toWorktreeWireError } from "./worktree-errors.js";
 import { parseGitRemoteLocation } from "@getpaseo/protocol/git-remote";
 import {
@@ -566,6 +576,8 @@ export interface SessionOptions {
   scriptRuntimeStore?: WorkspaceScriptRuntimeStore;
   workspaceSetupObservation?: WorkspaceSetupObservation;
   workspaceSetupRuntime?: WorkspaceSetupRuntime;
+  /** Shared by every session so an undo from any connection reaches the archive it cancels. */
+  workspaceArchiveOperations?: WorkspaceArchiveOperations;
   onBranchChanged?: (
     workspaceId: string,
     oldBranch: string | null,
@@ -837,6 +849,7 @@ export class Session {
   private readonly workspaceSetupObservation: WorkspaceSetupObservation;
   private readonly unsubscribeSetupObservation: () => void;
   private readonly workspaceSetupRuntime: WorkspaceSetupRuntime;
+  private readonly workspaceArchiveOperations: WorkspaceArchiveOperations;
   private readonly workspaceGitObserver: WorkspaceGitObserverService;
   private readonly workspaceDirectory: WorkspaceDirectory;
   private readonly voiceSessions: VoiceSessions;
@@ -902,6 +915,7 @@ export class Session {
       scriptRuntimeStore,
       workspaceSetupObservation,
       workspaceSetupRuntime,
+      workspaceArchiveOperations,
       onBranchChanged,
       getDaemonTcpPort,
       getDaemonTcpHost,
@@ -1249,6 +1263,7 @@ export class Session {
       },
     );
     this.workspaceSetupRuntime = resolveWorkspaceSetupRuntime(workspaceSetupRuntime);
+    this.workspaceArchiveOperations = resolveWorkspaceArchiveOperations(workspaceArchiveOperations);
     this.getDaemonTcpPort = getDaemonTcpPort ?? null;
     this.getDaemonTcpHost = getDaemonTcpHost ?? null;
     this.serviceProxyPublicBaseUrl = serviceProxyPublicBaseUrl ?? null;
@@ -3306,6 +3321,8 @@ export class Session {
         return this.handleWorkspaceRecoveryInspectRequest(msg);
       case "workspace.recovery.restore.request":
         return this.handleWorkspaceRecoveryRestoreRequest(msg);
+      case "workspace.archive.undo.request":
+        return this.handleWorkspaceArchiveUndoRequest(msg);
       case "workspace.clear_attention.request":
         return this.handleWorkspaceClearAttentionRequest(msg);
       case "workspace.mark_unread.request":
@@ -6180,6 +6197,10 @@ export class Session {
 
   private async restoreWorkspaceAndEmit(workspaceId: string): Promise<void> {
     await this.workspaceRecovery.restore(workspaceId);
+    await this.publishRecoveredWorkspace(workspaceId);
+  }
+
+  private async publishRecoveredWorkspace(workspaceId: string): Promise<void> {
     const workspace = await this.workspaceRegistry.get(workspaceId);
     if (!workspace) {
       throw new Error(`Recovered workspace record not found: ${workspaceId}`);
@@ -7786,41 +7807,62 @@ export class Session {
     request: Extract<SessionInboundMessage, { type: "archive_workspace_request" }>,
   ): Promise<void> {
     try {
-      const existing = await this.workspaceRegistry.get(request.workspaceId);
-      if (!existing) {
-        throw new Error(`Workspace not found: ${request.workspaceId}`);
-      }
-
-      await archiveByScope(
-        {
-          paseoHome: this.paseoHome,
-          paseoWorktreesBaseRoot: this.worktreesRoot,
-          github: this.github,
-          workspaceGitService: this.workspaceGitService,
-          agentManager: this.agentManager,
-          agentStorage: this.agentStorage,
-          findWorkspaceIdForCwd: (cwd) => this.findWorkspaceIdForCwd(cwd),
-          getWorkspace: (workspaceId) => this.workspaceRegistry.get(workspaceId),
-          listActiveWorkspaces: () => this.listActiveWorkspaceRefs(),
-          archiveWorkspaceRecord: (workspaceId) => this.archiveWorkspaceRecord(workspaceId),
-          emitWorkspaceUpdatesForWorkspaceIds: (workspaceIds) =>
-            this.emitWorkspaceUpdatesForWorkspaceIds(workspaceIds),
-          markWorkspaceArchiving: (workspaceIds, archivingAt) =>
-            this.markWorkspaceArchiving(workspaceIds, archivingAt),
-          clearWorkspaceArchiving: (workspaceIds) => this.clearWorkspaceArchiving(workspaceIds),
-          assertWorkspaceAutomationAllowed: (workspaceId) =>
-            assertWorkspaceAutomationAllowedForWorkspace(this.workspaceRegistry, workspaceId),
-          killTerminalsForWorkspace: (workspaceId) =>
-            this.terminalController.killTerminalsForWorkspace(workspaceId),
-          stopWorkspaceSetup: (workspaceId) => this.workspaceSetupRuntime.stop(workspaceId),
-          sessionLogger: this.sessionLogger,
-        },
-        {
-          scope: { kind: "workspace", workspaceId: existing.workspaceId },
-          requestId: request.requestId,
+      // Claim the archive queue before any await, so an undo sent right behind this request
+      // queues after it and cancels it instead of running first.
+      const outcome = await this.workspaceArchiveOperations.archive(
+        request.workspaceId,
+        async (signal) => {
+          const existing = await this.workspaceRegistry.get(request.workspaceId);
+          if (!existing) {
+            throw new Error(`Workspace not found: ${request.workspaceId}`);
+          }
+          return archiveByScope(
+            {
+              paseoHome: this.paseoHome,
+              paseoWorktreesBaseRoot: this.worktreesRoot,
+              github: this.github,
+              workspaceGitService: this.workspaceGitService,
+              agentManager: this.agentManager,
+              agentStorage: this.agentStorage,
+              findWorkspaceIdForCwd: (cwd) => this.findWorkspaceIdForCwd(cwd),
+              getWorkspace: (workspaceId) => this.workspaceRegistry.get(workspaceId),
+              listActiveWorkspaces: () => this.listActiveWorkspaceRefs(),
+              archiveWorkspaceRecord: (workspaceId) => this.archiveWorkspaceRecord(workspaceId),
+              emitWorkspaceUpdatesForWorkspaceIds: (workspaceIds) =>
+                this.emitWorkspaceUpdatesForWorkspaceIds(workspaceIds),
+              markWorkspaceArchiving: (workspaceIds, archivingAt) =>
+                this.markWorkspaceArchiving(workspaceIds, archivingAt),
+              clearWorkspaceArchiving: (workspaceIds) => this.clearWorkspaceArchiving(workspaceIds),
+              assertWorkspaceAutomationAllowed: (workspaceId) =>
+                assertWorkspaceAutomationAllowedForWorkspace(this.workspaceRegistry, workspaceId),
+              killTerminalsForWorkspace: (workspaceId) =>
+                this.terminalController.killTerminalsForWorkspace(workspaceId),
+              stopWorkspaceSetup: (workspaceId) => this.workspaceSetupRuntime.stop(workspaceId),
+              sessionLogger: this.sessionLogger,
+            },
+            {
+              scope: { kind: "workspace", workspaceId: existing.workspaceId },
+              requestId: request.requestId,
+              signal,
+            },
+          );
         },
       );
 
+      if (outcome.kind === "canceled") {
+        this.emit({
+          type: "archive_workspace_response",
+          payload: {
+            requestId: request.requestId,
+            workspaceId: request.workspaceId,
+            archivedAt: null,
+            error: "Workspace archive was undone",
+            canceled: true,
+          },
+        });
+        return;
+      }
+
       const archivedWorkspace = await this.workspaceRegistry.get(request.workspaceId);
       const archivedAt = archivedWorkspace?.archivedAt ?? new Date().toISOString();
       this.emit({
@@ -7850,6 +7892,69 @@ export class Session {
     }
   }
 
+  private async handleWorkspaceArchiveUndoRequest(
+    request: Extract<SessionInboundMessage, { type: "workspace.archive.undo.request" }>,
+  ): Promise<void> {
+    try {
+      await this.workspaceArchiveOperations.undo(request.workspaceId, (input) =>
+        this.restoreArchivedWorkspaceAndAgents(request.workspaceId, input),
+      );
+      this.emit({
+        type: "workspace.archive.undo.response",
+        payload: {
+          requestId: request.requestId,
+          workspaceId: request.workspaceId,
+          accepted: true,
+          error: null,
+        },
+      });
+    } catch (error) {
+      this.sessionLogger.warn(
+        { err: error, workspaceId: request.workspaceId, requestId: request.requestId },
+        "session: workspace.archive.undo.request rejected",
+      );
+      this.emit({
+        type: "workspace.archive.undo.response",
+        payload: {
+          requestId: request.requestId,
+          workspaceId: request.workspaceId,
+          accepted: false,
+          error: getErrorMessageOr(error, "Failed to undo the workspace archive"),
+        },
+      });
+    }
+  }
+
+  // Runs on the archive lane after any in-flight archive has stopped, so the record reflects how
+  // far it got: still active when it was canceled early, archived (directory kept or removed)
+  // otherwise.
+  private async restoreArchivedWorkspaceAndAgents(
+    workspaceId: string,
+    input: WorkspaceArchiveUndoInput,
+  ): Promise<void> {
+    const workspace = await this.workspaceRegistry.get(workspaceId);
+    if (!workspace) {
+      throw new Error(`Workspace not found: ${workspaceId}`);
+    }
+    if (workspace.archivedAt) {
+      await this.workspaceRecovery.restore(workspaceId);
+    }
+    const results = await Promise.allSettled(
+      input.agentIds.map((agentId) =>
+        unarchiveAgentState(this.agentStorage, this.agentManager, agentId),
+      ),
+    );
+    for (const [index, result] of results.entries()) {
+      if (result.status === "rejected") {
+        this.sessionLogger.warn(
+          { err: result.reason, workspaceId, agentId: input.agentIds[index] },
+          "Failed to unarchive agent while undoing workspace archive",
+        );
+      }
+    }
+    await this.publishRecoveredWorkspace(workspaceId);
+  }
+
   private async handleWorkspaceClearAttentionRequest(
     request: Extract<SessionInboundMessage, { type: "workspace.clear_attention.request" }>,
   ): Promise<void> {
diff --git a/packages/server/src/server/websocket-server.ts b/packages/server/src/server/websocket-server.ts
index 7c301556c3..74188b3d7a 100644
--- a/packages/server/src/server/websocket-server.ts
+++ b/packages/server/src/server/websocket-server.ts
@@ -65,6 +65,7 @@ import {
 import type { HubRelationshipManagement } from "./hub/relationship-controller.js";
 import { WorkspaceSetupObservation } from "./workspace-setup-observation.js";
 import { WorkspaceSetupRuntime } from "./workspace-setup-runtime.js";
+import { WorkspaceArchiveOperations } from "./workspace-archive-operations.js";
 import type { HubExecutionAgents } from "./hub/daemon-executions.js";
 import type { AgentProvider } from "./agent/agent-sdk-types.js";
 import { ProviderSnapshotManager } from "./agent/provider-snapshot-manager.js";
@@ -609,6 +610,9 @@ export class VoiceAssistantWebSocketServer {
   private readonly voiceCallerContexts = new Map<string, VoiceCallerContext>();
   private readonly workspaceSetupObservation = new WorkspaceSetupObservation();
   private readonly workspaceSetupRuntime: WorkspaceSetupRuntime;
+  // One lane per workspace across every connection, so an undo from any client can cancel an
+  // archive another connection started.
+  private readonly workspaceArchiveOperations = new WorkspaceArchiveOperations();
   private readonly providerSnapshotManager: ProviderSnapshotManager;
   private onLifecycleIntent!: ((intent: SessionLifecycleIntent) => void) | null;
   private onBranchChanged!:
@@ -1697,6 +1701,7 @@ export class VoiceAssistantWebSocketServer {
       scriptRuntimeStore: this.scriptRuntimeStore ?? undefined,
       workspaceSetupObservation: this.workspaceSetupObservation,
       workspaceSetupRuntime: this.workspaceSetupRuntime,
+      workspaceArchiveOperations: this.workspaceArchiveOperations,
       onBranchChanged: this.onBranchChanged ?? undefined,
       getDaemonTcpPort: this.getDaemonTcpPort ?? undefined,
       getDaemonTcpHost: this.getDaemonTcpHost ?? undefined,
@@ -2120,6 +2125,8 @@ export class VoiceAssistantWebSocketServer {
         worktreeRestore: true,
         // COMPAT(workspaceRecovery): added in v0.1.105, remove after 2027-01-11 once daemon floor >= v0.1.105.
         workspaceRecovery: true,
+        // COMPAT(workspaceArchiveUndo): added in v0.15.3, remove gate after 2027-05-06.
+        workspaceArchiveUndo: true,
         // COMPAT(workspaceFileEditing): added in v0.2.0, remove after 2027-01-18 once daemon floor >= v0.2.0.
         workspaceFileEditing: true,
         // COMPAT(fileByteWrites): added in v0.13.0, remove gate after 2027-04-20.
diff --git a/packages/server/src/server/workspace-archive-operations.test.ts b/packages/server/src/server/workspace-archive-operations.test.ts
new file mode 100644
index 0000000000..c262f58fa3
--- /dev/null
+++ b/packages/server/src/server/workspace-archive-operations.test.ts
@@ -0,0 +1,282 @@
+import { describe, expect, test } from "vitest";
+
+import { WorkspaceArchiveOperations } from "./workspace-archive-operations.js";
+import { type ArchiveResult, WorkspaceArchiveCanceledError } from "./workspace-archive-service.js";
+
+interface Deferred<T> {
+  promise: Promise<T>;
+  resolve: (value: T) => void;
+  reject: (error: unknown) => void;
+}
+
+function deferred<T = void>(): Deferred<T> {
+  let resolve!: (value: T) => void;
+  let reject!: (error: unknown) => void;
+  const promise = new Promise<T>((res, rej) => {
+    resolve = res;
+    reject = rej;
+  });
+  return { promise, resolve, reject };
+}
+
+function archived(newlyArchivedAgentIds: string[]): ArchiveResult {
+  return {
+    archivedAgentIds: newlyArchivedAgentIds,
+    newlyArchivedAgentIds,
+    archivedWorkspaceIds: ["ws"],
+    removedDirectory: false,
+  };
+}
+
+/**
+ * An archive that parks until released, then honours its abort signal the way archiveByScope's
+ * checkpoints do: an aborted run reports the agents it already took down.
+ */
+function parkedArchive(agentIds: string[]) {
+  const release = deferred();
+  const started = deferred();
+  let signal: AbortSignal | null = null;
+  return {
+    release: () => release.resolve(),
+    started: started.promise,
+    get aborted() {
+      return signal?.aborted ?? false;
+    },
+    run: async (runSignal: AbortSignal) => {
+      signal = runSignal;
+      started.resolve();
+      await release.promise;
+      if (runSignal.aborted) throw new WorkspaceArchiveCanceledError(agentIds, false);
+      return archived(agentIds);
+    },
+  };
+}
+
+describe("WorkspaceArchiveOperations", () => {
+  test("an undo during a running archive aborts it and restores the agents it took down", async () => {
+    const operations = new WorkspaceArchiveOperations();
+    const archive = parkedArchive(["agent-a", "agent-b"]);
+    const restored: string[][] = [];
+
+    const archiveDone = operations.archive("ws", archive.run);
+    await archive.started;
+    const undoDone = operations.undo("ws", async ({ agentIds }) => {
+      restored.push(agentIds);
+    });
+
+    expect(archive.aborted).toBe(true);
+    expect(restored).toEqual([]);
+    archive.release();
+
+    await expect(archiveDone).resolves.toEqual({ kind: "canceled" });
+    await undoDone;
+    expect(restored).toEqual([["agent-a", "agent-b"]]);
+  });
+
+  test("an undo after the archive finished restores the agents that archive took down", async () => {
+    const operations = new WorkspaceArchiveOperations();
+    await operations.archive("ws", async () => archived(["agent-a"]));
+
+    const restored: string[][] = [];
+    await operations.undo("ws", async ({ agentIds }) => {
+      restored.push(agentIds);
+    });
+
+    expect(restored).toEqual([["agent-a"]]);
+  });
+
+  test("restore runs only after the aborted archive has stopped", async () => {
+    const operations = new WorkspaceArchiveOperations();
+    const archive = parkedArchive([]);
+    const order: string[] = [];
+
+    const archiveDone = operations
+      .archive("ws", async (signal) => {
+        try {
+          return await archive.run(signal);
+        } finally {
+          order.push("archive stopped");
+        }
+      })
+      .catch(() => undefined);
+    await archive.started;
+    const undoDone = operations.undo("ws", async () => {
+      order.push("restore");
+    });
+    archive.release();
+    await Promise.all([archiveDone, undoDone]);
+
+    expect(order).toEqual(["archive stopped", "restore"]);
+  });
+
+  test("a second archive while one runs joins it instead of archiving twice", async () => {
+    const operations = new WorkspaceArchiveOperations();
+    const archive = parkedArchive(["agent-a"]);
+    let runs = 0;
+    const run = (signal: AbortSignal) => {
+      runs += 1;
+      return archive.run(signal);
+    };
+
+    const first = operations.archive("ws", run);
+    const second = operations.archive("ws", run);
+    archive.release();
+
+    await expect(Promise.all([first, second])).resolves.toEqual([
+      { kind: "archived", result: archived(["agent-a"]) },
+      { kind: "archived", result: archived(["agent-a"]) },
+    ]);
+    expect(runs).toBe(1);
+  });
+
+  test("an archive requested during an undo runs after the undo, and wins", async () => {
+    const operations = new WorkspaceArchiveOperations();
+    await operations.archive("ws", async () => archived(["agent-a"]));
+
+    const restoreGate = deferred();
+    const order: string[] = [];
+    const undoDone = operations.undo("ws", async () => {
+      await restoreGate.promise;
+      order.push("restored");
+    });
+    const rearchive = operations.archive("ws", async () => {
+      order.push("archived again");
+      return archived(["agent-a"]);
+    });
+
+    restoreGate.resolve();
+    await undoDone;
+    await expect(rearchive).resolves.toMatchObject({ kind: "archived" });
+    expect(order).toEqual(["restored", "archived again"]);
+  });
+
+  test("archive, undo, archive in quick succession leaves the workspace archived", async () => {
+    const operations = new WorkspaceArchiveOperations();
+    const first = parkedArchive(["agent-a"]);
+    const restored: string[][] = [];
+
+    const firstDone = operations.archive("ws", first.run);
+    await first.started;
+    const undoDone = operations.undo("ws", async ({ agentIds }) => {
+      restored.push(agentIds);
+    });
+    // The re-archive must not join the archive the undo just aborted.
+    const secondDone = operations.archive("ws", async () => archived(["agent-a"]));
+    first.release();
+
+    await expect(firstDone).resolves.toEqual({ kind: "canceled" });
+    await undoDone;
+    await expect(secondDone).resolves.toMatchObject({ kind: "archived" });
+    expect(restored).toEqual([["agent-a"]]);
+  });
+
+  test("a second undo while one runs joins it", async () => {
+    const operations = new WorkspaceArchiveOperations();
+    await operations.archive("ws", async () => archived(["agent-a"]));
+    const restoreGate = deferred();
+    let restores = 0;
+    const restore = async () => {
+      restores += 1;
+      await restoreGate.promise;
+    };
+
+    const first = operations.undo("ws", restore);
+    const second = operations.undo("ws", restore);
+    restoreGate.resolve();
+    await Promise.all([first, second]);
+
+    expect(restores).toBe(1);
+  });
+
+  test("a failed restore keeps the agents for a retry", async () => {
+    const operations = new WorkspaceArchiveOperations();
+    await operations.archive("ws", async () => archived(["agent-a"]));
+
+    await expect(
+      operations.undo("ws", async () => {
+        throw new Error("worktree recreation failed");
+      }),
+    ).rejects.toThrow("worktree recreation failed");
+
+    const restored: string[][] = [];
+    await operations.undo("ws", async ({ agentIds }) => {
+      restored.push(agentIds);
+    });
+    expect(restored).toEqual([["agent-a"]]);
+  });
+
+  test("an archive of an already archived workspace keeps the earlier archive's agents for undo", async () => {
+    const operations = new WorkspaceArchiveOperations();
+    await operations.archive("ws", async () => archived(["agent-a"]));
+    await operations.archive("ws", async () => ({
+      archivedAgentIds: ["agent-a"],
+      newlyArchivedAgentIds: [],
+      archivedWorkspaceIds: [],
+      removedDirectory: false,
+    }));
+    const restored: string[][] = [];
+
+    await operations.undo("ws", async ({ agentIds }) => {
+      restored.push(agentIds);
+    });
+
+    expect(restored).toEqual([["agent-a"]]);
+  });
+
+  test("an undo restores the archive's agents once; a repeat undo restores none", async () => {
+    const operations = new WorkspaceArchiveOperations();
+    await operations.archive("ws", async () => archived(["agent-a"]));
+    const restored: string[][] = [];
+    const restore = async ({ agentIds }: { agentIds: string[] }) => {
+      restored.push(agentIds);
+    };
+
+    await operations.undo("ws", restore);
+    await operations.undo("ws", restore);
+
+    expect(restored).toEqual([["agent-a"], []]);
+  });
+
+  test("an undo after the retention window restores the workspace without agents", async () => {
+    let now = 0;
+    const operations = new WorkspaceArchiveOperations({ undoRetentionMs: 1000, now: () => now });
+    await operations.archive("ws", async () => archived(["agent-a"]));
+    now = 1000;
+
+    const restored: string[][] = [];
+    await operations.undo("ws", async ({ agentIds }) => {
+      restored.push(agentIds);
+    });
+    expect(restored).toEqual([[]]);
+  });
+
+  test("workspaces have independent lanes", async () => {
+    const operations = new WorkspaceArchiveOperations();
+    const archive = parkedArchive(["agent-a"]);
+
+    const parked = operations.archive("ws-a", archive.run);
+    await archive.started;
+    await expect(operations.archive("ws-b", async () => archived(["agent-b"]))).resolves.toEqual({
+      kind: "archived",
+      result: archived(["agent-b"]),
+    });
+    await operations.undo("ws-b", async () => {});
+
+    expect(archive.aborted).toBe(false);
+    archive.release();
+    await expect(parked).resolves.toMatchObject({ kind: "archived" });
+  });
+
+  test("a failed archive frees the lane for the next request", async () => {
+    const operations = new WorkspaceArchiveOperations();
+    await expect(
+      operations.archive("ws", async () => {
+        throw new Error("registry unavailable");
+      }),
+    ).rejects.toThrow("registry unavailable");
+
+    await expect(operations.archive("ws", async () => archived([]))).resolves.toMatchObject({
+      kind: "archived",
+    });
+  });
+});
diff --git a/packages/server/src/server/workspace-archive-operations.ts b/packages/server/src/server/workspace-archive-operations.ts
new file mode 100644
index 0000000000..c8bb15a9d2
--- /dev/null
+++ b/packages/server/src/server/workspace-archive-operations.ts
@@ -0,0 +1,133 @@
+import { type ArchiveResult, WorkspaceArchiveCanceledError } from "./workspace-archive-service.js";
+
+export type WorkspaceArchiveOutcome =
+  | { kind: "archived"; result: ArchiveResult }
+  | { kind: "canceled" };
+
+export interface WorkspaceArchiveUndoInput {
+  /** Agents the undone archive took down. Empty when the daemon no longer remembers it. */
+  agentIds: string[];
+}
+
+type LaneEntry =
+  | { kind: "archiving"; controller: AbortController; done: Promise<WorkspaceArchiveOutcome> }
+  | { kind: "undoing"; done: Promise<void> };
+
+interface UndoableArchive {
+  agentIds: string[];
+  expiresAt: number;
+}
+
+const DEFAULT_UNDO_RETENTION_MS = 10 * 60_000;
+
+/**
+ * One lane per workspace for archive and its undo, shared by every session on the daemon.
+ *
+ * - An archive while one runs joins it.
+ * - An undo while an archive runs aborts it, waits for it to stop, then restores.
+ * - An archive while an undo runs waits for the undo, then archives.
+ * - An undo while an undo runs joins it.
+ *
+ * Each call claims the lane synchronously, so whichever request arrives last decides the
+ * workspace's final state no matter how the earlier work interleaves.
+ *
+ * The agents an archive took down are kept in memory for the undo window. An archive that took
+ * nothing down, such as a repeat archive from a stale client, leaves them alone. After a daemon
+ * restart, undo still restores the workspace but its agents stay archived.
+ */
+export class WorkspaceArchiveOperations {
+  private readonly lanes = new Map<string, LaneEntry>();
+  private readonly undoable = new Map<string, UndoableArchive>();
+  private readonly undoRetentionMs: number;
+  private readonly now: () => number;
+
+  constructor(options: { undoRetentionMs?: number; now?: () => number } = {}) {
+    this.undoRetentionMs = options.undoRetentionMs ?? DEFAULT_UNDO_RETENTION_MS;
+    this.now = options.now ?? Date.now;
+  }
+
+  archive(
+    workspaceId: string,
+    run: (signal: AbortSignal) => Promise<ArchiveResult>,
+  ): Promise<WorkspaceArchiveOutcome> {
+    const current = this.lanes.get(workspaceId);
+    if (current?.kind === "archiving") {
+      return current.done;
+    }
+    const controller = new AbortController();
+    const done = (async (): Promise<WorkspaceArchiveOutcome> => {
+      await settled(current?.done);
+      try {
+        const result = await run(controller.signal);
+        if (result.archivedWorkspaceIds.length > 0 || result.newlyArchivedAgentIds.length > 0) {
+          this.retainUndoable(workspaceId, result.newlyArchivedAgentIds);
+        }
+        return { kind: "archived", result };
+      } catch (error) {
+        if (!(error instanceof WorkspaceArchiveCanceledError)) throw error;
+        if (error.recordArchived || error.newlyArchivedAgentIds.length > 0) {
+          this.retainUndoable(workspaceId, error.newlyArchivedAgentIds);
+        }
+        return { kind: "canceled" };
+      }
+    })();
+    this.claim(workspaceId, { kind: "archiving", controller, done });
+    return done;
+  }
+
+  undo(
+    workspaceId: string,
+    restore: (input: WorkspaceArchiveUndoInput) => Promise<void>,
+  ): Promise<void> {
+    const current = this.lanes.get(workspaceId);
+    if (current?.kind === "undoing") {
+      return current.done;
+    }
+    current?.controller.abort();
+    const done = (async () => {
+      await settled(current?.done);
+      const agentIds = this.takeUndoable(workspaceId);
+      try {
+        await restore({ agentIds });
+      } catch (error) {
+        // Keep the agents for a retry; the archive they came from is still the latest one.
+        this.retainUndoable(workspaceId, agentIds);
+        throw error;
+      }
+    })();
+    this.claim(workspaceId, { kind: "undoing", done });
+    return done;
+  }
+
+  private claim(workspaceId: string, entry: LaneEntry): void {
+    this.lanes.set(workspaceId, entry);
+    const release = () => {
+      if (this.lanes.get(workspaceId) === entry) this.lanes.delete(workspaceId);
+    };
+    void (entry.done as Promise<unknown>).then(release, release);
+  }
+
+  private retainUndoable(workspaceId: string, agentIds: string[]): void {
+    const now = this.now();
+    for (const [id, entry] of this.undoable) {
+      if (entry.expiresAt <= now) this.undoable.delete(id);
+    }
+    this.undoable.set(workspaceId, { agentIds, expiresAt: now + this.undoRetentionMs });
+  }
+
+  private takeUndoable(workspaceId: string): string[] {
+    const entry = this.undoable.get(workspaceId);
+    this.undoable.delete(workspaceId);
+    if (!entry || entry.expiresAt <= this.now()) return [];
+    return entry.agentIds;
+  }
+}
+
+async function settled(promise: Promise<unknown> | undefined): Promise<void> {
+  if (!promise) return;
+  try {
+    await promise;
+  } catch {
+    // The earlier request reports its own failure; this one only waits for the lane.
+  }
+}
diff --git a/packages/server/src/server/workspace-archive-service.test.ts b/packages/server/src/server/workspace-archive-service.test.ts
index 43ba26b8ad..ecf4210ece 100644
--- a/packages/server/src/server/workspace-archive-service.test.ts
+++ b/packages/server/src/server/workspace-archive-service.test.ts
@@ -19,6 +19,7 @@ import {
   type ArchiveDependencies,
   type ArchiveResult,
   resolveWorkspaceIdAtPath,
+  WorkspaceArchiveCanceledError,
 } from "./workspace-archive-service.js";
 import { WorkspaceAutomationBlockedError } from "./workspace-automation-gate.js";
 
@@ -1019,6 +1020,207 @@ describe("archiveByScope", () => {
   });
 });
 
+function gate(): {
+  wait: Promise<void>;
+  open: () => void;
+  reached: Promise<void>;
+  reach: () => void;
+} {
+  let open!: () => void;
+  let reach!: () => void;
+  const wait = new Promise<void>((resolve) => {
+    open = resolve;
+  });
+  const reached = new Promise<void>((resolve) => {
+    reach = resolve;
+  });
+  return { wait, open, reached, reach };
+}
+
+async function canceledArchive(promise: Promise<unknown>): Promise<WorkspaceArchiveCanceledError> {
+  const error = await promise.then(
+    () => null,
+    (reason: unknown) => reason,
+  );
+  if (!(error instanceof WorkspaceArchiveCanceledError)) {
+    throw new Error(`Expected the archive to be canceled, got ${String(error)}`);
+  }
+  return error;
+}
+
+describe("archiveByScope cancellation", () => {
+  function storedAgents(
+    workspaceId: string,
+    agents: Array<{ id: string; archivedAt: string | null }>,
+  ) {
+    return {
+      listByWorkspace: async () =>
+        agents.map((agent) => ({ ...agent, workspaceId })) as StoredAgentRecord[],
+    } as Pick<AgentStorage, "listByWorkspace">;
+  }
+
+  test("an abort while agents archive keeps the record and reports only the agents it took down", async () => {
+    const { tempDir, repoDir } = createGitRepo();
+    const paseoHome = path.join(tempDir, ".paseo");
+    const worktree = await createPaseoOwnedWorktree(repoDir, paseoHome, "cancel-agents");
+    const workspaceId = "ws-cancel-agents";
+    const deps = createArchiveDeps({
+      paseoHome,
+      activeWorkspaces: [{ workspaceId, cwd: worktree.worktreePath, kind: "worktree" }],
+    });
+    deps.agentStorage = storedAgents(workspaceId, [
+      { id: "agent-active", archivedAt: null },
+      { id: "agent-already-archived", archivedAt: "2026-01-01T00:00:00.000Z" },
+    ]);
+    const agentArchive = gate();
+    deps.agentManager.archiveSnapshot = vi.fn(async (agentId: string) => {
+      agentArchive.reach();
+      await agentArchive.wait;
+      deps.archivedSnapshotIds.push(agentId);
+      return {} as StoredAgentRecord;
+    });
+    const controller = new AbortController();
+
+    const archive = archiveByScope(deps, {
+      scope: { kind: "workspace", workspaceId },
+      requestId: "req-cancel-agents",
+      signal: controller.signal,
+    });
+    await agentArchive.reached;
+    controller.abort();
+    agentArchive.open();
+    const error = await canceledArchive(archive);
+
+    expect({
+      newlyArchivedAgentIds: error.newlyArchivedAgentIds,
+      recordArchived: error.recordArchived,
+      activeWorkspaceIds: (await deps.listActiveWorkspaces()).map((w) => w.workspaceId),
+      directoryExists: existsSync(worktree.worktreePath),
+    }).toEqual({
+      newlyArchivedAgentIds: ["agent-active"],
+      recordArchived: false,
+      activeWorkspaceIds: [workspaceId],
+      directoryExists: true,
+    });
+    // The archiving marker never outlives a canceled archive.
+    expect(deps.clearWorkspaceArchiving).toHaveBeenCalledWith([workspaceId]);
+  });
+
+  test("an abort after the record archived keeps the worktree directory", async () => {
+    const { tempDir, repoDir } = createGitRepo();
+    const paseoHome = path.join(tempDir, ".paseo");
+    const worktree = await createPaseoOwnedWorktree(repoDir, paseoHome, "cancel-record");
+    const workspaceId = "ws-cancel-record";
+    const deps = createArchiveDeps({
+      paseoHome,
+      activeWorkspaces: [{ workspaceId, cwd: worktree.worktreePath, kind: "worktree" }],
+    });
+    const recordArchive = gate();
+    const archiveRecord = deps.archiveWorkspaceRecord;
+    deps.archiveWorkspaceRecord = async (id: string) => {
+      recordArchive.reach();
+      await recordArchive.wait;
+      await archiveRecord(id);
+    };
+    const controller = new AbortController();
+
+    const archive = archiveByScope(deps, {
+      scope: { kind: "workspace", workspaceId },
+      requestId: "req-cancel-record",
+      signal: controller.signal,
+    });
+    await recordArchive.reached;
+    controller.abort();
+    recordArchive.open();
+    const error = await canceledArchive(archive);
+
+    expect({
+      recordArchived: error.recordArchived,
+      activeWorkspaceIds: (await deps.listActiveWorkspaces()).map((w) => w.workspaceId),
+      directoryExists: existsSync(worktree.worktreePath),
+    }).toEqual({ recordArchived: true, activeWorkspaceIds: [], directoryExists: true });
+  });
+
+  test("an archive aborted before it starts touches nothing", async () => {
+    const { tempDir, repoDir } = createGitRepo();
+    const paseoHome = path.join(tempDir, ".paseo");
+    const worktree = await createPaseoOwnedWorktree(repoDir, paseoHome, "cancel-before");
+    const workspaceId = "ws-cancel-before";
+    const deps = createArchiveDeps({
+      paseoHome,
+      activeWorkspaces: [{ workspaceId, cwd: worktree.worktreePath, kind: "worktree" }],
+    });
+    deps.agentStorage = storedAgents(workspaceId, [{ id: "agent-active", archivedAt: null }]);
+    const controller = new AbortController();
+    controller.abort();
+
+    const error = await canceledArchive(
+      archiveByScope(deps, {
+        scope: { kind: "workspace", workspaceId },
+        requestId: "req-cancel-before",
+        signal: controller.signal,
+      }),
+    );
+
+    expect(error.newlyArchivedAgentIds).toEqual([]);
+    expect(deps.archivedSnapshotIds).toEqual([]);
+    expect(deps.markWorkspaceArchiving).not.toHaveBeenCalled();
+    expect(existsSync(worktree.worktreePath)).toBe(true);
+  });
+
+  test("a completed archive reports the agents it newly archived", async () => {
+    const { tempDir, repoDir } = createGitRepo();
+    const paseoHome = path.join(tempDir, ".paseo");
+    const worktree = await createPaseoOwnedWorktree(repoDir, paseoHome, "newly-archived");
+    const workspaceId = "ws-newly-archived";
+    const deps = createArchiveDeps({
+      paseoHome,
+      activeWorkspaces: [{ workspaceId, cwd: worktree.worktreePath, kind: "worktree" }],
+    });
+    deps.agentStorage = storedAgents(workspaceId, [
+      { id: "agent-active", archivedAt: null },
+      { id: "agent-already-archived", archivedAt: "2026-01-01T00:00:00.000Z" },
+    ]);
+
+    const result = await archiveByScope(deps, {
+      scope: { kind: "workspace", workspaceId },
+      requestId: "req-newly-archived",
+      signal: new AbortController().signal,
+    });
+
+    expect(result.archivedAgentIds.sort()).toEqual(["agent-active", "agent-already-archived"]);
+    expect(result.newlyArchivedAgentIds).toEqual(["agent-active"]);
+  });
+
+  test("an archived agent loaded to read its history is not reported as newly archived", async () => {
+    const { tempDir, repoDir } = createGitRepo();
+    const paseoHome = path.join(tempDir, ".paseo");
+    const worktree = await createPaseoOwnedWorktree(repoDir, paseoHome, "loaded-archived");
+    const workspaceId = "ws-loaded-archived";
+    const deps = createArchiveDeps({
+      paseoHome,
+      activeWorkspaces: [{ workspaceId, cwd: worktree.worktreePath, kind: "worktree" }],
+    });
+    deps.agentStorage = storedAgents(workspaceId, [
+      { id: "agent-active", archivedAt: null },
+      { id: "agent-history", archivedAt: "2026-01-01T00:00:00.000Z" },
+    ]);
+    deps.agentManager.listAgents = () =>
+      [
+        { id: "agent-active", workspaceId },
+        { id: "agent-history", workspaceId },
+      ] as ManagedAgent[];
+
+    const result = await archiveByScope(deps, {
+      scope: { kind: "workspace", workspaceId },
+      requestId: "req-loaded-archived",
+      signal: new AbortController().signal,
+    });
+
+    expect(result.newlyArchivedAgentIds).toEqual(["agent-active"]);
+  });
+});
+
 describe("resolveWorkspaceIdAtPath", () => {
   test("prefers the worktree-kind record on an exact cwd tie", async () => {
     const targetPath = "/worktrees/repo/feature";
diff --git a/packages/server/src/server/workspace-archive-service.ts b/packages/server/src/server/workspace-archive-service.ts
index 78f8c0b97d..54d772add1 100644
--- a/packages/server/src/server/workspace-archive-service.ts
+++ b/packages/server/src/server/workspace-archive-service.ts
@@ -67,6 +67,9 @@ export type ArchiveScope =
 
 export interface ArchiveResult {
   archivedAgentIds: string[];
+  // Agents this request moved from active to archived. `archivedAgentIds` also lists agents that
+  // were already archived; undo must restore only the ones this archive took down.
+  newlyArchivedAgentIds: string[];
   archivedWorkspaceIds: string[];
   removedDirectory: boolean;
   // Set when the record archived but its worktree directory was left on
@@ -78,6 +81,24 @@ export interface ArchiveResult {
 export interface ArchiveByScopeRequest {
   scope: ArchiveScope;
   requestId: string;
+  // Aborting cancels the archive at its next checkpoint. Removing the worktree directory is the
+  // point of no return: once it starts the archive completes.
+  signal?: AbortSignal;
+}
+
+/**
+ * The archive stopped at a checkpoint because its signal aborted. Whatever ran before the
+ * checkpoint stays done; `newlyArchivedAgentIds` and `recordArchived` say how far it got so the
+ * canceller can put it back.
+ */
+export class WorkspaceArchiveCanceledError extends Error {
+  constructor(
+    public readonly newlyArchivedAgentIds: string[],
+    public readonly recordArchived: boolean,
+  ) {
+    super("Workspace archive was canceled");
+    this.name = "WorkspaceArchiveCanceledError";
+  }
 }
 
 export async function requireActiveWorkspaceForArchive(
@@ -144,10 +165,22 @@ async function archiveByScopeWithPriority(
   dependencies: ArchiveDependencies,
   request: ArchiveByScopeRequest,
 ): Promise<ArchiveResult> {
+  const progress: ArchiveProgress = { newlyArchivedAgentIds: new Set(), recordArchived: false };
+  const checkpoint = () => {
+    if (request.signal?.aborted) {
+      throw new WorkspaceArchiveCanceledError(
+        Array.from(progress.newlyArchivedAgentIds),
+        progress.recordArchived,
+      );
+    }
+  };
+
+  checkpoint();
   const target = await resolveArchiveTarget(dependencies, request.scope);
   const targetWorkspaceIds = target.workspaceIds;
 
   await stopWorkspaceSetups(dependencies, target.setupWorkspaceIds, request.requestId);
+  checkpoint();
 
   if (targetWorkspaceIds.length > 0) {
     dependencies.markWorkspaceArchiving(targetWorkspaceIds, new Date().toISOString());
@@ -160,12 +193,14 @@ async function archiveByScopeWithPriority(
     if (targetWorkspaceIds.length > 0) {
       await dependencies.emitWorkspaceUpdatesForWorkspaceIds(targetWorkspaceIds);
     }
+    checkpoint();
 
     const { archivedAgents, archivedWorkspaceIds } = await archiveTargetRecords(
       dependencies,
       targetWorkspaceIds,
-      request.requestId,
+      { requestId: request.requestId, checkpoint, progress },
     );
+    checkpoint();
 
     if (target.backing?.mainRepoRoot) {
       try {
@@ -184,7 +219,7 @@ async function archiveByScopeWithPriority(
     if (target.backing !== null) {
       const removal = await maybeRemoveDirectory(
         dependencies,
-        request,
+        { requestId: request.requestId, checkpoint },
         target,
         archivedWorkspaceIds,
       );
@@ -194,6 +229,7 @@ async function archiveByScopeWithPriority(
 
     return {
       archivedAgentIds: Array.from(archivedAgents),
+      newlyArchivedAgentIds: Array.from(progress.newlyArchivedAgentIds),
       archivedWorkspaceIds,
       removedDirectory,
       ...(directoryLeftBehind ? { directoryLeftBehind } : {}),
@@ -206,6 +242,11 @@ async function archiveByScopeWithPriority(
   }
 }
 
+interface ArchiveProgress {
+  newlyArchivedAgentIds: Set<string>;
+  recordArchived: boolean;
+}
+
 async function resolveArchiveTarget(
   dependencies: ArchiveDependencies,
   scope: ArchiveScope,
@@ -352,16 +393,23 @@ async function resolveBackingDirectory(
 async function archiveTargetRecords(
   dependencies: ArchiveDependencies,
   targetWorkspaceIds: string[],
-  requestId: string,
+  options: { requestId: string; checkpoint: () => void; progress: ArchiveProgress },
 ): Promise<{ archivedAgents: Set<string>; archivedWorkspaceIds: string[] }> {
   const archivedAgents = new Set<string>();
   const archivedWorkspaceIds: string[] = [];
 
   const results = await Promise.allSettled(
     targetWorkspaceIds.map(async (workspaceId) => {
-      const agents = await archiveWorkspaceContents(dependencies, workspaceId);
+      const contents = await archiveWorkspaceContentsWithProgress(dependencies, workspaceId);
+      for (const agentId of contents.newlyArchivedAgentIds) {
+        options.progress.newlyArchivedAgentIds.add(agentId);
+      }
+      // Agents and terminals are down, the record is not: an abort here leaves the workspace
+      // listed, and the canceller restores the agents it reports.
+      options.checkpoint();
       await dependencies.archiveWorkspaceRecord(workspaceId);
-      return { workspaceId, agents };
+      options.progress.recordArchived = true;
+      return { workspaceId, agents: contents.agentIds };
     }),
   );
 
@@ -371,9 +419,14 @@ async function archiveTargetRecords(
       for (const agentId of result.value.agents) {
         archivedAgents.add(agentId);
       }
+    } else if (result.reason instanceof WorkspaceArchiveCanceledError) {
+      throw new WorkspaceArchiveCanceledError(
+        Array.from(options.progress.newlyArchivedAgentIds),
+        options.progress.recordArchived,
+      );
     } else {
       dependencies.sessionLogger?.warn(
-        { err: result.reason, requestId },
+        { err: result.reason, requestId: options.requestId },
         "archiveByScope workspace teardown failed; continuing",
       );
     }
@@ -384,7 +437,7 @@ async function archiveTargetRecords(
 
 async function maybeRemoveDirectory(
   dependencies: ArchiveDependencies,
-  request: Pick<ArchiveByScopeRequest, "requestId">,
+  request: { requestId: string; checkpoint: () => void },
   target: ArchiveTarget,
   archivedWorkspaceIds: string[],
 ): Promise<{
@@ -423,6 +476,7 @@ async function maybeRemoveDirectory(
       teardownTargets,
     );
     for (const teardownTarget of uniqueTeardownTargets(allowedTeardownTargets)) {
+      request.checkpoint();
       await runWorktreeTeardownCommands({
         worktreePath: backing.path,
         teardownCwd: teardownTarget.cwd,
@@ -452,6 +506,9 @@ async function maybeRemoveDirectory(
     return { removedDirectory: false };
   }
 
+  // Last chance to keep the directory. Teardown commands already ran, so a cancel here restores
+  // a workspace whose teardown hooks fired; that beats deleting what the user asked to keep.
+  request.checkpoint();
   try {
     await deletePaseoWorktree({
       cwd: backing.mainRepoRoot,
@@ -518,6 +575,13 @@ export async function archiveWorkspaceContents(
   dependencies: ArchiveWorkspaceContentsDependencies,
   workspaceId: string,
 ): Promise<Set<string>> {
+  return (await archiveWorkspaceContentsWithProgress(dependencies, workspaceId)).agentIds;
+}
+
+async function archiveWorkspaceContentsWithProgress(
+  dependencies: ArchiveWorkspaceContentsDependencies,
+  workspaceId: string,
+): Promise<{ agentIds: Set<string>; newlyArchivedAgentIds: string[] }> {
   const archivedAgents = new Set<string>();
 
   const liveAgents = dependencies.agentManager
@@ -542,29 +606,52 @@ export async function archiveWorkspaceContents(
   }
 
   const archivedAt = new Date().toISOString();
-  const agentIdsToArchive = new Set([
-    ...liveAgents.map((agent) => agent.id),
-    ...matchingStoredRecords.filter((record) => !record.archivedAt).map((record) => record.id),
-  ]);
-  const archiveResults = await Promise.allSettled([
-    ...[...agentIdsToArchive].map((agentId) =>
-      dependencies.agentManager.getAgent(agentId)
-        ? dependencies.agentManager.archiveAgent(agentId)
-        : dependencies.agentManager.archiveSnapshot(agentId, archivedAt),
+  const agentIdsToArchive = [
+    ...new Set([
+      ...liveAgents.map((agent) => agent.id),
+      ...matchingStoredRecords.filter((record) => !record.archivedAt).map((record) => record.id),
+    ]),
+  ];
+  // Undo brings back only what this archive took down. Internal agents are retired rather than
+  // archived, and an agent loaded only to read its history was archived before this request.
+  const restorableAgentIds = new Set(agentIdsToArchive);
+  for (const agent of liveAgents) {
+    if (agent.internal) restorableAgentIds.delete(agent.id);
+  }
+  for (const record of matchingStoredRecords) {
+    if (record.archivedAt) restorableAgentIds.delete(record.id);
+  }
+  const [agentResults, [terminalResult]] = await Promise.all([
+    Promise.allSettled(
+      agentIdsToArchive.map((agentId) =>
+        dependencies.agentManager.getAgent(agentId)
+          ? dependencies.agentManager.archiveAgent(agentId)
+          : dependencies.agentManager.archiveSnapshot(agentId, archivedAt),
+      ),
     ),
-    dependencies.killTerminalsForWorkspace(workspaceId),
+    Promise.allSettled([dependencies.killTerminalsForWorkspace(workspaceId)]),
   ]);
 
-  for (const result of archiveResults) {
+  const newlyArchivedAgentIds: string[] = [];
+  for (const [index, result] of agentResults.entries()) {
+    const agentId = agentIdsToArchive[index]!;
     if (result.status === "rejected") {
       dependencies.sessionLogger?.warn(
-        { err: result.reason, workspaceId },
+        { err: result.reason, workspaceId, agentId },
         "Workspace archive teardown step failed; continuing",
       );
+    } else if (restorableAgentIds.has(agentId)) {
+      newlyArchivedAgentIds.push(agentId);
     }
   }
+  if (terminalResult?.status === "rejected") {
+    dependencies.sessionLogger?.warn(
+      { err: terminalResult.reason, workspaceId },
+      "Workspace archive teardown step failed; continuing",
+    );
+  }
 
-  return archivedAgents;
+  return { agentIds: archivedAgents, newlyArchivedAgentIds };
 }
 
 // True when, after archiving
diff --git a/packages/server/src/server/workspace-archive-undo.e2e.test.ts b/packages/server/src/server/workspace-archive-undo.e2e.test.ts
new file mode 100644
index 0000000000..674e99415b
--- /dev/null
+++ b/packages/server/src/server/workspace-archive-undo.e2e.test.ts
@@ -0,0 +1,275 @@
+import { execFileSync } from "node:child_process";
+import { existsSync, mkdtempSync, rmSync, writeFileSync } from "node:fs";
+import { tmpdir } from "node:os";
+import path from "node:path";
+import { afterEach, beforeEach, expect, test } from "vitest";
+
+import { getFullAccessConfig } from "./daemon-e2e/agent-configs.js";
+import { createDaemonTestContext, type DaemonTestContext } from "./test-utils/index.js";
+
+// Undo of a workspace archive, end to end through a real daemon. The archive is parked inside a
+// worktree teardown command that waits on a file, so the undo lands at a known point.
+
+let ctx: DaemonTestContext;
+const tempRoots: string[] = [];
+
+beforeEach(async () => {
+  ctx = await createDaemonTestContext();
+});
+
+afterEach(async () => {
+  await ctx.cleanup();
+  for (const tempRoot of tempRoots.splice(0)) {
+    rmSync(tempRoot, { recursive: true, force: true });
+  }
+});
+
+interface GatedRepo {
+  repoDir: string;
+  teardownStartedPath: string;
+  releaseTeardown: () => void;
+}
+
+function git(repoDir: string, args: string[]): void {
+  execFileSync("git", args, { cwd: repoDir, stdio: "pipe" });
+}
+
+/** A repo whose worktree teardown parks until released. */
+function createRepoWithGatedTeardown(): GatedRepo {
+  const tempRoot = mkdtempSync(path.join(tmpdir(), "workspace-archive-undo-"));
+  tempRoots.push(tempRoot);
+  const repoDir = path.join(tempRoot, "repo");
+  const teardownStartedPath = path.join(tempRoot, "teardown-started");
+  const releasePath = path.join(tempRoot, "release-teardown");
+  execFileSync("git", ["init", "-b", "main", repoDir], { stdio: "pipe" });
+  git(repoDir, ["config", "user.email", "test@getpaseo.local"]);
+  git(repoDir, ["config", "user.name", "Paseo Test"]);
+  const teardown = `node -e "const fs=require('fs');fs.writeFileSync('${teardownStartedPath}','started');const timer=setInterval(()=>{if(fs.existsSync('${releasePath}'))clearInterval(timer)},20)"`;
+  writeFileSync(
+    path.join(repoDir, "paseo.json"),
+    JSON.stringify({ worktree: { teardown: [teardown] } }),
+  );
+  git(repoDir, ["add", "paseo.json"]);
+  git(repoDir, ["-c", "commit.gpgsign=false", "commit", "-m", "gated teardown"]);
+  return {
+    repoDir,
+    teardownStartedPath,
+    releaseTeardown: () => writeFileSync(releasePath, "release\n"),
+  };
+}
+
+async function createWorktreeWorkspaceWithAgent(repoDir: string, slug: string) {
+  const result = await ctx.client.createWorkspace({
+    source: { kind: "worktree", cwd: repoDir, worktreeSlug: slug, baseBranch: "main" },
+  });
+  const workspace = result.workspace;
+  if (!workspace?.workspaceDirectory) {
+    throw new Error(result.error ?? "Failed to create worktree workspace");
+  }
+  const agent = await ctx.client.createAgent({
+    ...getFullAccessConfig("codex"),
+    cwd: workspace.workspaceDirectory,
+    workspaceId: workspace.id,
+    title: "Undo agent",
+  });
+  return { workspaceId: workspace.id, directory: workspace.workspaceDirectory, agentId: agent.id };
+}
+
+async function isWorkspaceActive(workspaceId: string): Promise<boolean> {
+  const workspaces = await ctx.client.fetchWorkspaces();
+  return workspaces.entries.some((entry) => entry.id === workspaceId);
+}
+
+async function isAgentArchived(agentId: string): Promise<boolean> {
+  const agents = await ctx.client.fetchAgents({ filter: { includeArchived: true } });
+  const entry = agents.entries.find((candidate) => candidate.agent.id === agentId);
+  if (!entry) throw new Error(`Agent ${agentId} is missing`);
+  return entry.agent.archivedAt !== null && entry.agent.archivedAt !== undefined;
+}
+
+test.skipIf(process.platform === "win32")(
+  "an undo while teardown runs cancels the archive before the worktree is deleted",
+  async () => {
+    const repo = createRepoWithGatedTeardown();
+    const { workspaceId, directory, agentId } = await createWorktreeWorkspaceWithAgent(
+      repo.repoDir,
+      "undo-during-teardown",
+    );
+
+    try {
+      const archive = ctx.client.archiveWorkspace(workspaceId);
+      await expect.poll(() => existsSync(repo.teardownStartedPath), { timeout: 15000 }).toBe(true);
+      const undo = ctx.client.undoWorkspaceArchive(workspaceId);
+      repo.releaseTeardown();
+
+      const [archiveResponse] = await Promise.all([archive, undo]);
+
+      expect({
+        canceled: archiveResponse.canceled,
+        archivedAt: archiveResponse.archivedAt,
+        workspaceActive: await isWorkspaceActive(workspaceId),
+        directoryExists: existsSync(directory),
+        agentArchived: await isAgentArchived(agentId),
+      }).toEqual({
+        canceled: true,
+        archivedAt: null,
+        workspaceActive: true,
+        directoryExists: true,
+        agentArchived: false,
+      });
+    } finally {
+      repo.releaseTeardown();
+    }
+  },
+  60000,
+);
+
+test.skipIf(process.platform === "win32")(
+  "an undo after the archive finished recreates the worktree and its agents",
+  async () => {
+    const repo = createRepoWithGatedTeardown();
+    repo.releaseTeardown();
+    const { workspaceId, directory, agentId } = await createWorktreeWorkspaceWithAgent(
+      repo.repoDir,
+      "undo-after-archive",
+    );
+
+    const archived = await ctx.client.archiveWorkspace(workspaceId);
+    expect(archived.error).toBeNull();
+    expect(existsSync(directory)).toBe(false);
+    expect(await isAgentArchived(agentId)).toBe(true);
+
+    await ctx.client.undoWorkspaceArchive(workspaceId);
+
+    expect({
+      workspaceActive: await isWorkspaceActive(workspaceId),
+      directoryExists: existsSync(directory),
+      agentArchived: await isAgentArchived(agentId),
+    }).toEqual({ workspaceActive: true, directoryExists: true, agentArchived: false });
+  },
+  60000,
+);
+
+test.skipIf(process.platform === "win32")(
+  "archive, undo, archive leaves the workspace archived",
+  async () => {
+    const repo = createRepoWithGatedTeardown();
+    const { workspaceId, directory, agentId } = await createWorktreeWorkspaceWithAgent(
+      repo.repoDir,
+      "archive-undo-archive",
+    );
+
+    try {
+      const first = ctx.client.archiveWorkspace(workspaceId);
+      await expect.poll(() => existsSync(repo.teardownStartedPath), { timeout: 15000 }).toBe(true);
+      const undo = ctx.client.undoWorkspaceArchive(workspaceId);
+      const second = ctx.client.archiveWorkspace(workspaceId);
+      repo.releaseTeardown();
+
+      const [firstResponse, , secondResponse] = await Promise.all([first, undo, second]);
+
+      expect({
+        firstCanceled: firstResponse.canceled,
+        secondError: secondResponse.error,
+        secondCanceled: secondResponse.canceled ?? false,
+        workspaceActive: await isWorkspaceActive(workspaceId),
+        directoryExists: existsSync(directory),
+        agentArchived: await isAgentArchived(agentId),
+      }).toEqual({
+        firstCanceled: true,
+        secondError: null,
+        secondCanceled: false,
+        workspaceActive: false,
+        directoryExists: false,
+        agentArchived: true,
+      });
+    } finally {
+      repo.releaseTeardown();
+    }
+  },
+  60000,
+);
+
+test.skipIf(process.platform === "win32")(
+  "an undo sent right behind its archive leaves the workspace active",
+  async () => {
+    const repo = createRepoWithGatedTeardown();
+    repo.releaseTeardown();
+    const { workspaceId, directory, agentId } = await createWorktreeWorkspaceWithAgent(
+      repo.repoDir,
+      "archive-then-undo-same-tick",
+    );
+
+    const [archiveResponse] = await Promise.all([
+      ctx.client.archiveWorkspace(workspaceId),
+      ctx.client.undoWorkspaceArchive(workspaceId),
+    ]);
+
+    expect({
+      archiveCanceled: archiveResponse.canceled ?? false,
+      workspaceActive: await isWorkspaceActive(workspaceId),
+      directoryExists: existsSync(directory),
+      agentArchived: await isAgentArchived(agentId),
+    }).toEqual({
+      archiveCanceled: true,
+      workspaceActive: true,
+      directoryExists: true,
+      agentArchived: false,
+    });
+  },
+  60000,
+);
+
+test.skipIf(process.platform === "win32")(
+  "the undo response arrives after the client has seen its agents restored",
+  async () => {
+    const repo = createRepoWithGatedTeardown();
+    repo.releaseTeardown();
+    const { workspaceId, agentId } = await createWorktreeWorkspaceWithAgent(
+      repo.repoDir,
+      "undo-update-order",
+    );
+    await ctx.client.fetchAgents({ subscribe: {} });
+    // An archived agent leaves a default subscription; a restored one comes back as active.
+    let seenState: "active" | "archived" | "removed" = "active";
+    const stop = ctx.client.on("agent_update", (message) => {
+      if (message.payload.kind === "remove" && message.payload.agentId === agentId) {
+        seenState = "removed";
+      }
+      if (message.payload.kind === "upsert" && message.payload.agent.id === agentId) {
+        seenState = message.payload.agent.archivedAt ? "archived" : "active";
+      }
+    });
+
+    try {
+      await ctx.client.archiveWorkspace(workspaceId);
+      await expect.poll(() => seenState, { timeout: 15000 }).not.toBe("active");
+
+      await ctx.client.undoWorkspaceArchive(workspaceId);
+
+      // An app holds its agent tabs open until this response; an agent it still sees as
+      // archived at that point gets its tab closed.
+      expect(seenState).toBe("active");
+    } finally {
+      stop();
+    }
+  },
+  60000,
+);
+
+test("an undo on a workspace that was never archived leaves it as it was", async () => {
+  const repo = createRepoWithGatedTeardown();
+  repo.releaseTeardown();
+  const { workspaceId, directory, agentId } = await createWorktreeWorkspaceWithAgent(
+    repo.repoDir,
+    "undo-without-archive",
+  );
+
+  await ctx.client.undoWorkspaceArchive(workspaceId);
+
+  expect({
+    workspaceActive: await isWorkspaceActive(workspaceId),
+    directoryExists: existsSync(directory),
+    agentArchived: await isAgentArchived(agentId),
+  }).toEqual({ workspaceActive: true, directoryExists: true, agentArchived: false });
+}, 60000);