diff --git a/apps/web/src/components/Sidebar.tsx b/apps/web/src/components/Sidebar.tsx
index f054b3deedc..e71ba2afe0f 100644
--- a/apps/web/src/components/Sidebar.tsx
+++ b/apps/web/src/components/Sidebar.tsx
@@ -1600,6 +1600,7 @@ export default function Sidebar() {
   const keybindings = useAtomValue(primaryServerKeybindingsAtom);
   const autoSettleAfterDays = useClientSettings((s) => s.sidebarAutoSettleAfterDays);
   const confirmThreadDelete = useClientSettings((s) => s.confirmThreadDelete);
+  const confirmThreadArchive = useClientSettings((s) => s.confirmThreadArchive);
   const sidebarProjectSortOrder = useClientSettings((s) => s.sidebarProjectSortOrder);
   const timestampFormat = useClientSettings((s) => s.timestampFormat);
   const projectGroupingSettings = useClientSettings(selectProjectGroupingSettings);
@@ -1611,6 +1612,7 @@ export default function Sidebar() {
     pinThread,
     unpinThread,
     reorderPinnedThread,
+    archiveThread,
     deleteThread,
   } = useThreadActions();
   const updateThreadMetadata = useAtomCommand(threadEnvironment.updateMetadata, {
@@ -2962,6 +2964,8 @@ export default function Sidebar() {
               isSnoozed,
               canSnoozeNow: canSnooze(thread, { now: new Date().toISOString() }),
               isRegeneratingTitle,
+              isRunning:
+                thread.session?.status === "running" && thread.session.activeTurnId != null,
               supports: {
                 settlement: supportsSettlement,
                 snooze: supportsSnooze,
@@ -3065,6 +3069,34 @@ export default function Sidebar() {
           case "copy-thread-id":
             copyThreadIdToClipboard(thread.id, { threadId: thread.id });
             return;
+          case "archive": {
+            if (confirmThreadArchive) {
+              const confirmed = await settlePromise(() =>
+                api.dialogs.confirm(`Archive thread "${thread.title}"?`),
+              );
+              if (confirmed._tag === "Failure" || !confirmed.value) return;
+            }
+            let didArchive = false;
+            const result = await archiveThread(threadRef, {
+              onArchived: () => {
+                didArchive = true;
+              },
+            });
+            if (result._tag === "Failure" && !isAtomCommandInterrupted(result)) {
+              const error = squashAtomCommandFailure(result);
+              toastManager.add(
+                stackedThreadToast({
+                  type: "error",
+                  title: didArchive
+                    ? "Thread archived, but navigation failed"
+                    : "Failed to archive thread",
+                  description: error instanceof Error ? error.message : "An error occurred.",
+                }),
+              );
+              return;
+            }
+            return;
+          }
           case "delete": {
             if (confirmThreadDelete) {
               const confirmed = await settlePromise(() =>
@@ -3098,12 +3130,14 @@ export default function Sidebar() {
       })();
     },
     [
+      archiveThread,
       attemptPin,
       attemptSettle,
       attemptSnooze,
       attemptUnpin,
       attemptUnsettle,
       attemptUnsnooze,
+      confirmThreadArchive,
       confirmThreadDelete,
       copyBranchToClipboard,
       copyPathToClipboard,
diff --git a/apps/web/src/components/threadActionMenu.logic.test.ts b/apps/web/src/components/threadActionMenu.logic.test.ts
index 93dc653e7c0..c839ddc3be7 100644
--- a/apps/web/src/components/threadActionMenu.logic.test.ts
+++ b/apps/web/src/components/threadActionMenu.logic.test.ts
@@ -9,6 +9,7 @@ const baseState: ThreadActionMenuState = {
   isSnoozed: false,
   canSnoozeNow: true,
   isRegeneratingTitle: false,
+  isRunning: false,
   supports: { settlement: true, snooze: true, pinning: true, titleRegeneration: true },
   snoozePresets: [
     { id: "hour", label: "In 1 hour", whenLabel: "3:00 PM", snoozedUntil: "2026-08-07T15:00:00Z" },
@@ -26,7 +27,7 @@ describe("buildThreadActionMenuItems", () => {
         ...baseState,
         supports: { settlement: false, snooze: false, pinning: false, titleRegeneration: false },
       }),
-    ).toEqual(["rename", "mark-unread", "copy-path", "copy-thread-id", "delete"]);
+    ).toEqual(["rename", "mark-unread", "copy-path", "copy-thread-id", "archive", "delete"]);
   });
 
   it("includes branch items only for threads with a branch", () => {
@@ -63,4 +64,28 @@ describe("buildThreadActionMenuItems", () => {
     const items = buildThreadActionMenuItems({ ...baseState, branch: "main" });
     expect(items.at(-1)).toMatchObject({ id: "delete", destructive: true });
   });
+
+  it("offers archive as a non-destructive action right before delete", () => {
+    const items = buildThreadActionMenuItems(baseState);
+    const archiveItem = items.at(-2);
+    expect(archiveItem?.id).toBe("archive");
+    expect(archiveItem?.destructive).toBeFalsy();
+    expect(items.at(-1)?.id).toBe("delete");
+  });
+
+  it("keeps archive available even when the environment lacks every other capability", () => {
+    expect(
+      ids({
+        ...baseState,
+        supports: { settlement: false, snooze: false, pinning: false, titleRegeneration: false },
+      }),
+    ).toContain("archive");
+  });
+
+  it("disables archive while the thread is running", () => {
+    const archiveItem = buildThreadActionMenuItems({ ...baseState, isRunning: true }).find(
+      (item) => item.id === "archive",
+    );
+    expect(archiveItem?.disabled).toBe(true);
+  });
 });
diff --git a/apps/web/src/components/threadActionMenu.logic.ts b/apps/web/src/components/threadActionMenu.logic.ts
index ef4b38dcdac..44c2e907ca5 100644
--- a/apps/web/src/components/threadActionMenu.logic.ts
+++ b/apps/web/src/components/threadActionMenu.logic.ts
@@ -21,6 +21,7 @@ export type ThreadActionMenuId =
   | "copy-path"
   | "copy-branch"
   | "copy-thread-id"
+  | "archive"
   | "delete";
 
 export interface ThreadActionMenuState {
@@ -30,6 +31,8 @@ export interface ThreadActionMenuState {
   readonly isSnoozed: boolean;
   readonly canSnoozeNow: boolean;
   readonly isRegeneratingTitle: boolean;
+  /** Archive rejects a thread with an active turn, so disable it here rather than let the action fail. */
+  readonly isRunning: boolean;
   readonly supports: {
     readonly settlement: boolean;
     readonly snooze: boolean;
@@ -102,6 +105,12 @@ export function buildThreadActionMenuItems(
     { id: "copy-path", label: "Copy path", icon: "copy" },
     ...(state.branch ? [{ id: "copy-branch" as const, label: "Copy branch", icon: "copy" }] : []),
     { id: "copy-thread-id", label: "Copy thread ID", icon: "copy" },
+    // Archive removes the thread from the sidebar while keeping its
+    // conversation under Settings > Archived threads — distinct from Settle
+    // (stays visible in the Settled shelf) and Delete (clears history for
+    // good), so it sits beside Delete without borrowing its destructive
+    // styling.
+    { id: "archive", label: "Archive thread", disabled: state.isRunning },
     { id: "delete", label: "Delete", destructive: true, icon: "trash" },
   ];
 }
diff --git a/apps/web/src/hooks/useThreadActionMenu.ts b/apps/web/src/hooks/useThreadActionMenu.ts
index 4eac13fddb3..7ebc634f074 100644
--- a/apps/web/src/hooks/useThreadActionMenu.ts
+++ b/apps/web/src/hooks/useThreadActionMenu.ts
@@ -72,6 +72,7 @@ export function useThreadActionMenu(input: {
     unsnoozeThread,
     pinThread,
     unpinThread,
+    archiveThread,
     deleteThread,
   } = useThreadActions();
   const updateThreadMetadata = useAtomCommand(threadEnvironment.updateMetadata, {
@@ -81,6 +82,7 @@ export function useThreadActionMenu(input: {
   const markThreadUnread = useUiStateStore((s) => s.markThreadUnread);
   const autoSettleAfterDays = useClientSettings((s) => s.sidebarAutoSettleAfterDays);
   const confirmThreadDelete = useClientSettings((s) => s.confirmThreadDelete);
+  const confirmThreadArchive = useClientSettings((s) => s.confirmThreadArchive);
   const timestampFormat = useClientSettings((s) => s.timestampFormat);
   const { copyToClipboard: copyPathToClipboard } = useCopyToClipboard<{ path: string }>({
     onCopy: ({ path }) => {
@@ -137,6 +139,7 @@ export function useThreadActionMenu(input: {
           isSnoozed: supports.snooze && effectiveSnoozed(thread, { now: now.toISOString() }),
           canSnoozeNow: canSnooze(thread, { now: now.toISOString() }),
           isRegeneratingTitle,
+          isRunning: thread.session?.status === "running" && thread.session.activeTurnId != null,
           supports,
           snoozePresets,
         });
@@ -251,6 +254,27 @@ export function useThreadActionMenu(input: {
           case "copy-thread-id":
             copyThreadIdToClipboard(thread.id, { threadId: thread.id });
             return;
+          case "archive": {
+            if (confirmThreadArchive) {
+              const confirmed = await settlePromise(() =>
+                api.dialogs.confirm(`Archive thread "${thread.title}"?`),
+              );
+              if (confirmed._tag === "Failure" || !confirmed.value) return;
+            }
+            let didArchive = false;
+            const result = await archiveThread(threadRef, {
+              onArchived: () => {
+                didArchive = true;
+              },
+            });
+            if (result._tag === "Failure" && !isAtomCommandInterrupted(result)) {
+              failureToast(
+                didArchive ? "Thread archived, but navigation failed" : "Failed to archive thread",
+                squashAtomCommandFailure(result),
+              );
+            }
+            return;
+          }
           case "delete": {
             if (confirmThreadDelete) {
               const confirmed = await settlePromise(() =>
@@ -283,8 +307,10 @@ export function useThreadActionMenu(input: {
       })();
     },
     [
+      archiveThread,
       autoSettleAfterDays,
       changeRequestState,
+      confirmThreadArchive,
       confirmThreadDelete,
       copyBranchToClipboard,
       copyPathToClipboard,