diff --git a/src/components/layout/app-shell/AppShell.test.tsx b/src/components/layout/app-shell/AppShell.test.tsx
index 27676f6fc..3d5fc1f47 100644
--- a/src/components/layout/app-shell/AppShell.test.tsx
+++ b/src/components/layout/app-shell/AppShell.test.tsx
@@ -143,7 +143,11 @@ describe("AppShell agent sidebar pass-through", () => {
     fireEvent.keyDown(input, { key: "Enter" });
     expect(onRename).toHaveBeenCalledWith("h1", "New title");
 
+    // Delete opens a confirmation dialog first; the forwarded handler fires
+    // only after the user clicks the destructive confirm button.
     fireEvent.click(screen.getByLabelText("Delete conversation"));
+    expect(onDelete).not.toHaveBeenCalled();
+    fireEvent.click(screen.getByRole("button", { name: "Delete" }));
     expect(onDelete).toHaveBeenCalledWith("h1");
   });
 
diff --git a/src/components/layout/app-shell/AppShell.tsx b/src/components/layout/app-shell/AppShell.tsx
index 3a1a700d3..6d58af848 100644
--- a/src/components/layout/app-shell/AppShell.tsx
+++ b/src/components/layout/app-shell/AppShell.tsx
@@ -118,11 +118,12 @@ export interface AppShellProps {
   /** Enables the hover rename affordance on agent history rows.
    *  Called with the trimmed title (1-200 chars) when the user commits an inline rename. */
   onRenameAgentConversation?: AgentSidebarHeaderProps["onRenameConversation"];
-  /** Enables the hover delete affordance on agent history rows. Confirmation
-   *  (if any) is the consumer's responsibility; the kit fires immediately. */
+  /** Enables the hover delete affordance on agent history rows. Clicking it
+   *  opens a destructive confirmation dialog first; this fires only once the
+   *  user confirms (cancel/dismiss does nothing). */
   onDeleteAgentConversation?: AgentSidebarHeaderProps["onDeleteConversation"];
-  /** Label overrides for the agent header (history, rename, new-chat strings).
-   *  All have EN defaults. */
+  /** Label overrides for the agent header (history, rename, new-chat, and the
+   *  delete-confirmation dialog strings). All have EN defaults. */
   agentHeaderLabels?: AgentSidebarHeaderProps["labels"];
   /** Messages waiting to send once the current reply finishes — rendered as
    *  cancellable rows above the agent input, in send order. Display-only:
diff --git a/src/components/ui/agent/sidebar/AgentSidebar.stories.tsx b/src/components/ui/agent/sidebar/AgentSidebar.stories.tsx
index 9b5e82f23..27c3f7d3b 100644
--- a/src/components/ui/agent/sidebar/AgentSidebar.stories.tsx
+++ b/src/components/ui/agent/sidebar/AgentSidebar.stories.tsx
@@ -125,7 +125,9 @@ export const ActiveLastTab: StoryObj = {
   },
 };
 
-/** History row actions: hover edit (inline rename) + hover delete. */
+/** History row actions: hover edit (inline rename) + hover delete. Delete
+ *  opens a destructive confirmation dialog; onDeleteConversation fires only
+ *  on confirm. */
 export const History: StoryObj = {
   render: () => {
     const [history, setHistory] = useState<AgentSidebarHistoryGroup[]>(mockAgentHistory);
diff --git a/src/components/ui/agent/sidebar/AgentSidebar.test.tsx b/src/components/ui/agent/sidebar/AgentSidebar.test.tsx
index e41023f7f..51f8e119f 100644
--- a/src/components/ui/agent/sidebar/AgentSidebar.test.tsx
+++ b/src/components/ui/agent/sidebar/AgentSidebar.test.tsx
@@ -1,6 +1,7 @@
 import { cleanup, render, screen, fireEvent } from "@testing-library/react";
 import { describe, expect, it, vi, afterEach, beforeAll, afterAll } from "vitest";
 import { AgentSidebarHeader } from "./AgentSidebarHeader";
+import type { AgentSidebarHeaderProps } from "./AgentSidebarHeader";
 import { AgentSidebarInput } from "./AgentSidebarInput";
 import type { AgentSidebarHistoryGroup, ChatTab } from "./types";
 
@@ -250,6 +251,7 @@ describe("AgentSidebarHeader history delete", () => {
   const renderHistory = (props?: {
     onDelete?: (id: string) => void;
     onSelect?: (id: string) => void;
+    labels?: AgentSidebarHeaderProps["labels"];
   }) =>
     render(
       <AgentSidebarHeader
@@ -259,10 +261,12 @@ describe("AgentSidebarHeader history delete", () => {
         history={historyData}
         onSelectHistoryItem={props?.onSelect ?? (() => {})}
         onDeleteConversation={props?.onDelete}
+        labels={props?.labels}
       />,
     );
 
   const openHistory = () => fireEvent.click(screen.getByLabelText("Chat history"));
+  const clickDelete = () => fireEvent.click(screen.getByLabelText("Delete conversation"));
 
   it("shows the delete button when onDeleteConversation is provided", () => {
     renderHistory({ onDelete: () => {} });
@@ -276,14 +280,69 @@ describe("AgentSidebarHeader history delete", () => {
     expect(screen.queryByLabelText("Delete conversation")).not.toBeInTheDocument();
   });
 
-  it("calls onDeleteConversation with the row id, without opening the conversation", () => {
+  it("opens a confirmation dialog instead of deleting immediately", () => {
     const onDelete = vi.fn();
     const onSelect = vi.fn();
     renderHistory({ onDelete, onSelect });
     openHistory();
-    fireEvent.click(screen.getByLabelText("Delete conversation"));
+    clickDelete();
+    // Dialog is shown; nothing deleted or opened yet.
+    expect(screen.getByRole("dialog")).toBeInTheDocument();
+    expect(screen.getByText("Delete conversation?")).toBeInTheDocument();
+    expect(onDelete).not.toHaveBeenCalled();
+    expect(onSelect).not.toHaveBeenCalled();
+  });
+
+  it("calls onDeleteConversation with the row id only after confirm", () => {
+    const onDelete = vi.fn();
+    const onSelect = vi.fn();
+    renderHistory({ onDelete, onSelect });
+    openHistory();
+    clickDelete();
+    fireEvent.click(screen.getByRole("button", { name: "Delete" }));
     expect(onDelete).toHaveBeenCalledWith("h-1");
+    expect(onDelete).toHaveBeenCalledTimes(1);
     expect(onSelect).not.toHaveBeenCalled();
+    // Dialog closes after confirm.
+    expect(screen.queryByRole("dialog")).not.toBeInTheDocument();
+  });
+
+  it("does not delete when the dialog is cancelled", () => {
+    const onDelete = vi.fn();
+    renderHistory({ onDelete });
+    openHistory();
+    clickDelete();
+    fireEvent.click(screen.getByRole("button", { name: "Cancel" }));
+    expect(onDelete).not.toHaveBeenCalled();
+    expect(screen.queryByRole("dialog")).not.toBeInTheDocument();
+  });
+
+  it("does not delete when the dialog is dismissed via Escape", () => {
+    const onDelete = vi.fn();
+    renderHistory({ onDelete });
+    openHistory();
+    clickDelete();
+    fireEvent.keyDown(document, { key: "Escape" });
+    expect(onDelete).not.toHaveBeenCalled();
+    expect(screen.queryByRole("dialog")).not.toBeInTheDocument();
+  });
+
+  it("uses overridable labels for the confirm dialog", () => {
+    renderHistory({
+      onDelete: () => {},
+      labels: {
+        deleteConfirmTitle: "Eliminar conversación?",
+        deleteConfirmMessage: "Se eliminará de forma permanente.",
+        deleteConfirmConfirmLabel: "Eliminar",
+        deleteConfirmCancelLabel: "Cancelar",
+      },
+    });
+    openHistory();
+    clickDelete();
+    expect(screen.getByText("Eliminar conversación?")).toBeInTheDocument();
+    expect(screen.getByText("Se eliminará de forma permanente.")).toBeInTheDocument();
+    expect(screen.getByRole("button", { name: "Eliminar" })).toBeInTheDocument();
+    expect(screen.getByRole("button", { name: "Cancelar" })).toBeInTheDocument();
   });
 });
 
diff --git a/src/components/ui/agent/sidebar/AgentSidebarHeader.tsx b/src/components/ui/agent/sidebar/AgentSidebarHeader.tsx
index a6add0ee0..1e26c42cb 100644
--- a/src/components/ui/agent/sidebar/AgentSidebarHeader.tsx
+++ b/src/components/ui/agent/sidebar/AgentSidebarHeader.tsx
@@ -5,6 +5,7 @@ import { isDev } from "@/utils/env";
 import { IconButton } from "@/components/ui/actions/icon-button/IconButton";
 import { Icon } from "@/components/ui/media/icon/Icon";
 import { Notch } from "@/components/ui/surfaces/notch/Notch";
+import { Dialog } from "@/components/ui/surfaces/dialog/Dialog";
 import { useClickOutside } from "@/hooks/useClickOutside";
 import type { AgentSidebarHeaderLabels, AgentSidebarHistoryGroup, ChatTab } from "./types";
 
@@ -29,8 +30,9 @@ export interface AgentSidebarHeaderProps {
   /** Enables the hover rename affordance on history rows.
    *  Called with the trimmed title (1-200 chars) when the user commits an inline rename. */
   onRenameConversation?: (id: string, title: string) => void;
-  /** Enables the hover delete affordance on history rows. Confirmation (if any)
-   *  is the consumer's responsibility; the kit fires immediately. */
+  /** Enables the hover delete affordance on history rows. Clicking it opens a
+   *  destructive confirmation dialog first; this fires only once the user
+   *  confirms (cancel/dismiss does nothing). */
   onDeleteConversation?: (id: string) => void;
   /** Label overrides. All have EN defaults. */
   labels?: AgentSidebarHeaderLabels;
@@ -125,6 +127,11 @@ export function AgentSidebarHeader({
   const [editValue, setEditValue] = useState("");
   const editInputRef = useRef<HTMLInputElement>(null);
 
+  // Id of the conversation pending a delete confirmation; null = dialog closed.
+  // Deletion only fires once the user confirms, so a misclick on the row's
+  // trash icon can't silently remove a conversation.
+  const [deletingId, setDeletingId] = useState<string | null>(null);
+
   const calculateVisible = useCallback(() => {
     if (!tabsContainerRef.current) return;
     // clientWidth includes the strip's own pl-10 + pr-3 padding — subtract
@@ -416,7 +423,7 @@ export function AgentSidebarHeader({
                                   <button
                                     type="button"
                                     className="w-5 h-5 flex items-center justify-center rounded-full cursor-pointer text-on-surface opacity-70 hover:opacity-100 hover:bg-error/10 hover:text-error shrink-0"
-                                    onClick={(e) => { e.stopPropagation(); onDeleteConversation(item.id); }}
+                                    onClick={(e) => { e.stopPropagation(); setDeletingId(item.id); }}
                                     aria-label={labels?.deleteConversationLabel ?? "Delete conversation"}
                                   >
                                     <Icon name="delete" size={12} />
@@ -565,6 +572,36 @@ export function AgentSidebarHeader({
           </div>
         </div>
       )}
+
+      {/* Destructive delete confirmation. onDeleteConversation fires only on
+          confirm; Cancel, Escape, and backdrop click all just close the
+          dialog (via setDeletingId(null)) so a misclick is recoverable. */}
+      <Dialog
+        open={deletingId !== null}
+        onClose={() => setDeletingId(null)}
+        title={labels?.deleteConfirmTitle ?? "Delete conversation?"}
+        actions={[
+          {
+            label: labels?.deleteConfirmCancelLabel ?? "Cancel",
+            variant: "text",
+            onClick: () => setDeletingId(null),
+          },
+          {
+            label: labels?.deleteConfirmConfirmLabel ?? "Delete",
+            variant: "filled",
+            color: "error",
+            onClick: () => {
+              if (deletingId !== null) onDeleteConversation?.(deletingId);
+              setDeletingId(null);
+            },
+          },
+        ]}
+      >
+        <p className="text-sm text-on-surface-variant">
+          {labels?.deleteConfirmMessage ??
+            "This conversation will be permanently deleted."}
+        </p>
+      </Dialog>
     </div>
   );
 }
diff --git a/src/components/ui/agent/sidebar/types.ts b/src/components/ui/agent/sidebar/types.ts
index a2d6cd1e6..1ea0f283b 100644
--- a/src/components/ui/agent/sidebar/types.ts
+++ b/src/components/ui/agent/sidebar/types.ts
@@ -24,6 +24,15 @@ export interface AgentSidebarHeaderLabels {
   cancelRenameLabel?: string;
   /** aria-label on the delete icon button in a history row. Default: "Delete conversation" */
   deleteConversationLabel?: string;
+  /** Title of the delete-confirmation dialog. Default: "Delete conversation?" */
+  deleteConfirmTitle?: string;
+  /** Body text of the delete-confirmation dialog.
+   *  Default: "This conversation will be permanently deleted." */
+  deleteConfirmMessage?: string;
+  /** Label on the destructive confirm button in the delete dialog. Default: "Delete" */
+  deleteConfirmConfirmLabel?: string;
+  /** Label on the cancel button in the delete dialog. Default: "Cancel" */
+  deleteConfirmCancelLabel?: string;
   /** aria-label on the + button and text of the overflow new-chat entry. Default: "New chat" */
   newChatLabel?: string;
 }