diff --git a/app/src/App.tsx b/app/src/App.tsx
index bfebfe4..23f64f1 100644
--- a/app/src/App.tsx
+++ b/app/src/App.tsx
@@ -21,7 +21,9 @@ import { useTerminal } from "./hooks/useTerminal";
 import { useSTT } from "./hooks/useSTT";
 import { useContainerProgress } from "./hooks/useContainerProgress";
 import { useKeyboardShortcuts } from "./hooks/useKeyboardShortcuts";
-import { useAppState, isHomeTab, tabKeyId, homeTabKey } from "./store/appState";
+import { useMarketplaceSyncToasts } from "./hooks/useMarketplace";
+import MarketplaceView from "./components/marketplace/MarketplaceView";
+import { useAppState, isHomeTab, tabKeyId, homeTabKey, MARKETPLACE_TAB_KEY } from "./store/appState";
 import { reconcileProjectStatuses } from "./lib/tauri-commands";
 
 export default function App() {
@@ -72,6 +74,7 @@ export default function App() {
 
   useContainerProgress();
   useKeyboardShortcuts();
+  useMarketplaceSyncToasts();
 
   // Initialize on mount
   useEffect(() => {
@@ -159,6 +162,11 @@ export default function App() {
                   />
                 </PaneVisibilityProvider>
               ))}
+              {tabOrder.includes(MARKETPLACE_TAB_KEY) && (
+                <PaneVisibilityProvider visible={activeTabKey === MARKETPLACE_TAB_KEY}>
+                  <MarketplaceView active={activeTabKey === MARKETPLACE_TAB_KEY} />
+                </PaneVisibilityProvider>
+              )}
             </div>
           )}
         </main>
diff --git a/app/src/components/layout/MainTabs.test.tsx b/app/src/components/layout/MainTabs.test.tsx
index 855b789..f82dd22 100644
--- a/app/src/components/layout/MainTabs.test.tsx
+++ b/app/src/components/layout/MainTabs.test.tsx
@@ -1,7 +1,7 @@
 import { describe, it, expect, vi, beforeEach } from "vitest";
 import { fireEvent, render, screen } from "@testing-library/react";
 import MainTabs from "./MainTabs";
-import { useAppState, homeTabKey, terminalTabKey } from "../../store/appState";
+import { useAppState, homeTabKey, terminalTabKey, MARKETPLACE_TAB_KEY } from "../../store/appState";
 import type { Project, TerminalSession } from "../../lib/types";
 
 const close = vi.fn();
@@ -265,3 +265,20 @@ describe("MainTabs reordering", () => {
     }
   });
 });
+
+describe("marketplace tab", () => {
+  beforeEach(() => {
+    useAppState.setState({
+      tabOrder: [HOME, MARKETPLACE_TAB_KEY],
+      activeTabKey: MARKETPLACE_TAB_KEY,
+      activeSessionId: null,
+    });
+  });
+
+  it("renders a Marketplace tab that closes", () => {
+    render(<MainTabs />);
+    expect(screen.getByRole("tab", { name: /marketplace/i })).toHaveAttribute("aria-selected", "true");
+    fireEvent.click(screen.getByRole("button", { name: "Close Marketplace tab" }));
+    expect(useAppState.getState().tabOrder).toEqual([HOME]);
+  });
+});
diff --git a/app/src/components/layout/MainTabs.tsx b/app/src/components/layout/MainTabs.tsx
index bf356e2..d13648b 100644
--- a/app/src/components/layout/MainTabs.tsx
+++ b/app/src/components/layout/MainTabs.tsx
@@ -5,6 +5,7 @@ import { useProjects } from "../../hooks/useProjects";
 import {
   useAppState,
   isHomeTab,
+  isMarketplaceTab,
   tabKeyId,
   terminalTabKey,
 } from "../../store/appState";
@@ -41,12 +42,13 @@ const MODE_BADGE: Record<PermissionMode, { text: string; className: string }> =
 export default function MainTabs() {
   const { sessions, close } = useTerminal();
   const { projects, update } = useProjects();
-  const { tabOrder, activeTabKey, setActiveTabKey, closeHomeTab, moveTab } = useAppState(
+  const { tabOrder, activeTabKey, setActiveTabKey, closeHomeTab, closeMarketplaceTab, moveTab } = useAppState(
     useShallow((s) => ({
       tabOrder: s.tabOrder,
       activeTabKey: s.activeTabKey,
       setActiveTabKey: s.setActiveTabKey,
       closeHomeTab: s.closeHomeTab,
+      closeMarketplaceTab: s.closeMarketplaceTab,
       moveTab: s.moveTab,
     })),
   );
@@ -192,6 +194,7 @@ export default function MainTabs() {
    * worse than no ghost.
    */
   const tabLabel = (key: string): string => {
+    if (isMarketplaceTab(key)) return "Marketplace";
     if (isHomeTab(key)) {
       return projects.find((p) => p.id === tabKeyId(key))?.name ?? "";
     }
@@ -272,7 +275,7 @@ export default function MainTabs() {
         x: e.clientX - drag.offsetX,
         y: drag.top,
         label: tabLabel(drag.key),
-        icon: isHomeTab(drag.key) ? "⌂" : "▣",
+        icon: isMarketplaceTab(drag.key) ? "◈" : isHomeTab(drag.key) ? "⌂" : "▣",
       });
     },
     onPointerUp: (e: React.PointerEvent<HTMLDivElement>) => {
@@ -314,6 +317,41 @@ export default function MainTabs() {
   const renderTab = (key: string, index: number) => {
     const active = activeTabKey === key;
 
+    if (isMarketplaceTab(key)) {
+      return (
+        <div
+          role="tab"
+          aria-selected={active}
+          tabIndex={0}
+          data-tab-index={index}
+          onClick={() => activateTab(key)}
+          onKeyDown={(e) => {
+            if (e.key === "Enter" || e.key === " ") {
+              e.preventDefault();
+              setActiveTabKey(key);
+            }
+          }}
+          {...pointerProps(key, false)}
+          className={tabClass(active, dragKey === key)}
+        >
+          <span aria-hidden="true" className="text-[var(--text-secondary)]">◈</span>
+          <span className="truncate max-w-[160px]">Marketplace</span>
+          <button
+            type="button"
+            onClick={(e) => {
+              e.stopPropagation();
+              closeMarketplaceTab();
+            }}
+            aria-label="Close Marketplace tab"
+            title="Close tab"
+            className="w-6 h-6 flex items-center justify-center rounded-[var(--radius-control)] text-[var(--text-secondary)] hover:text-[var(--error)] hover:bg-[var(--bg-tertiary)] transition-colors"
+          >
+            <span aria-hidden="true">×</span>
+          </button>
+        </div>
+      );
+    }
+
     if (isHomeTab(key)) {
       const projectId = tabKeyId(key);
       const project = projects.find((p) => p.id === projectId);
diff --git a/app/src/components/layout/NotesDock.tsx b/app/src/components/layout/NotesDock.tsx
index 4619bb1..e16320e 100644
--- a/app/src/components/layout/NotesDock.tsx
+++ b/app/src/components/layout/NotesDock.tsx
@@ -78,7 +78,7 @@ export default function NotesDock() {
   if (!notesDockOpen) return null;
 
   // Follow whatever is in front: a home tab is its own project, a terminal tab
-  // is the project it belongs to.
+  // is the project it belongs to. The Marketplace tab belongs to no project.
   let projectId: string | null = null;
   if (activeTabKey && isHomeTab(activeTabKey)) {
     projectId = tabKeyId(activeTabKey);
diff --git a/app/src/components/marketplace/AccountsPane.test.tsx b/app/src/components/marketplace/AccountsPane.test.tsx
new file mode 100644
index 0000000..5c5b3bb
--- /dev/null
+++ b/app/src/components/marketplace/AccountsPane.test.tsx
@@ -0,0 +1,75 @@
+import { describe, it, expect, vi, beforeEach } from "vitest";
+import { fireEvent, render, screen, waitFor } from "@testing-library/react";
+import { useAppState } from "../../store/appState";
+import type { AppSettings } from "../../lib/types";
+import type { MarketplaceApi } from "../../hooks/useMarketplace";
+
+const testMarketplaceAccount = vi.fn();
+const removeMarketplaceAccount = vi.fn();
+vi.mock("../../lib/tauri-commands", () => ({
+  testMarketplaceAccount: (id: string) => testMarketplaceAccount(id),
+  removeMarketplaceAccount: (id: string) => removeMarketplaceAccount(id),
+}));
+vi.mock("./AddAccountModal", () => ({ default: () => <div>add account modal</div> }));
+
+import AccountsPane from "./AccountsPane";
+
+const settings = {
+  marketplace_accounts: [
+    { id: "a1", label: "Personal", host: "github.com", method: "gh_host", username: "me" },
+    { id: "a2", label: "Gitea", host: "repo.example.com", method: "token", username: "jk" },
+  ],
+  marketplaces: [{ id: "m1", name: "Team", url: "https://repo.example.com/t/m.git", branch: null, account_id: "a2" }],
+  global_marketplace_installs: [],
+} as unknown as AppSettings;
+
+describe("AccountsPane", () => {
+  beforeEach(() => {
+    vi.clearAllMocks();
+    useAppState.setState({ appSettings: settings, toasts: [] });
+  });
+
+  it("lists accounts with their method and usage", () => {
+    render(<AccountsPane mp={{} as MarketplaceApi} />);
+    expect(screen.getByText("Personal")).toBeInTheDocument();
+    expect(screen.getByText(/gh on this computer/)).toBeInTheDocument();
+    expect(screen.getByText(/Used by Team$/)).toBeInTheDocument();
+  });
+
+  it("tests an account", async () => {
+    testMarketplaceAccount.mockResolvedValue("me");
+    render(<AccountsPane mp={{} as MarketplaceApi} />);
+    fireEvent.click(screen.getByRole("button", { name: "Test Personal" }));
+    await waitFor(() => expect(useAppState.getState().toasts[0]).toMatchObject({ kind: "success" }));
+    expect(useAppState.getState().toasts[0].message).toContain("me");
+  });
+
+  // F5: the backend refuses to remove an account a marketplace uses, so the
+  // UI must not promise otherwise with a confirm modal — Remove is disabled
+  // with a hint instead, and there is no confirm step to click through.
+  it("disables Remove for an account in use, with a hint", () => {
+    render(<AccountsPane mp={{} as MarketplaceApi} />);
+    const removeGitea = screen.getByRole("button", { name: "Remove Gitea" });
+    expect(removeGitea).toHaveAttribute("aria-disabled", "true");
+    expect(screen.getByText(/Used by Team.*change or remove that marketplace first/)).toBeInTheDocument();
+    fireEvent.click(removeGitea);
+    expect(removeMarketplaceAccount).not.toHaveBeenCalled();
+    expect(screen.queryByRole("dialog")).not.toBeInTheDocument();
+  });
+
+  it("removes an unused account", async () => {
+    removeMarketplaceAccount.mockResolvedValue({ ...settings, marketplace_accounts: [settings.marketplace_accounts[1]] });
+    render(<AccountsPane mp={{} as MarketplaceApi} />);
+    const removePersonal = screen.getByRole("button", { name: "Remove Personal" });
+    expect(removePersonal).not.toHaveAttribute("aria-disabled");
+    fireEvent.click(removePersonal);
+    await waitFor(() => expect(removeMarketplaceAccount).toHaveBeenCalledWith("a1"));
+    await waitFor(() => expect(useAppState.getState().appSettings!.marketplace_accounts).toHaveLength(1));
+  });
+
+  it("opens the add dialog", () => {
+    render(<AccountsPane mp={{} as MarketplaceApi} />);
+    fireEvent.click(screen.getByRole("button", { name: "Add account" }));
+    expect(screen.getByText("add account modal")).toBeInTheDocument();
+  });
+});
diff --git a/app/src/components/marketplace/AccountsPane.tsx b/app/src/components/marketplace/AccountsPane.tsx
new file mode 100644
index 0000000..6f28255
--- /dev/null
+++ b/app/src/components/marketplace/AccountsPane.tsx
@@ -0,0 +1,108 @@
+import { useState } from "react";
+import type { MarketplaceApi } from "../../hooks/useMarketplace";
+import { useAppState } from "../../store/appState";
+import { removeMarketplaceAccount, testMarketplaceAccount } from "../../lib/tauri-commands";
+import type { AccountMethod, MarketplaceAccount } from "../../lib/types";
+import Button from "../ui/Button";
+import AddAccountModal from "./AddAccountModal";
+
+const METHOD_LABEL: Record<AccountMethod, string> = {
+  gh_host: "GitHub — gh on this computer",
+  gh_container: "GitHub — signed in via container",
+  token: "Access token",
+};
+
+export default function AccountsPane(_props: { mp: MarketplaceApi }) {
+  const appSettings = useAppState((s) => s.appSettings);
+  const setAppSettings = useAppState((s) => s.setAppSettings);
+  const pushToast = useAppState((s) => s.pushToast);
+  const [adding, setAdding] = useState(false);
+  const [testing, setTesting] = useState<string | null>(null);
+  const [removing, setRemoving] = useState<string | null>(null);
+
+  const accounts = appSettings?.marketplace_accounts ?? [];
+  const marketplaces = appSettings?.marketplaces ?? [];
+  const usedBy = (id: string) => marketplaces.filter((m) => m.account_id === id).map((m) => m.name);
+
+  const test = async (a: MarketplaceAccount) => {
+    setTesting(a.id);
+    try {
+      const login = await testMarketplaceAccount(a.id);
+      pushToast({ kind: "success", message: `${a.label} works — signed in as ${login}` });
+    } catch (e) {
+      pushToast({ kind: "error", message: `${a.label} could not sign in`, detail: String(e) });
+    } finally {
+      setTesting(null);
+    }
+  };
+
+  const remove = async (a: MarketplaceAccount) => {
+    setRemoving(a.id);
+    try {
+      setAppSettings(await removeMarketplaceAccount(a.id));
+    } catch (e) {
+      pushToast({ kind: "error", message: `Could not remove ${a.label}`, detail: String(e) });
+    } finally {
+      setRemoving(null);
+    }
+  };
+
+  return (
+    <div className="p-4 space-y-3 max-w-3xl">
+      <div className="flex items-center justify-between">
+        <p className="text-xs text-[var(--text-secondary)]">
+          Accounts are used to fetch private marketplaces. Tokens are kept in your OS keychain and never enter
+          containers.
+        </p>
+        <Button size="md" variant="secondary" onClick={() => setAdding(true)}>
+          Add account
+        </Button>
+      </div>
+      {accounts.length === 0 && <p className="text-xs text-[var(--text-secondary)]">No accounts yet. Public repositories need none.</p>}
+      <ul className="space-y-2">
+        {accounts.map((a) => {
+          const users = usedBy(a.id);
+          const inUse = users.length > 0;
+          return (
+            <li
+              key={a.id}
+              className="flex items-center justify-between gap-2 p-2 rounded-[var(--radius-control)] border border-[var(--border-color)]"
+            >
+              <div className="min-w-0 text-xs">
+                <p className="font-medium">{a.label}</p>
+                <p className="text-[var(--text-secondary)]">
+                  {METHOD_LABEL[a.method]} · {a.host}
+                  {a.username ? ` · ${a.username}` : ""}
+                </p>
+                {inUse && <p className="text-[var(--text-secondary)]">Used by {users.join(", ")}</p>}
+              </div>
+              <div className="flex gap-1 flex-shrink-0">
+                <Button
+                  size="sm"
+                  variant="ghost"
+                  aria-label={`Test ${a.label}`}
+                  disabled={testing === a.id}
+                  onClick={() => void test(a)}
+                >
+                  {testing === a.id ? "Testing…" : "Test"}
+                </Button>
+                <Button
+                  size="sm"
+                  variant="ghost"
+                  aria-label={`Remove ${a.label}`}
+                  disabled={removing === a.id}
+                  unavailable={inUse}
+                  unavailableReason={`Used by ${users.join(", ")} — change or remove that marketplace first`}
+                  onClick={() => void remove(a)}
+                >
+                  Remove
+                </Button>
+              </div>
+            </li>
+          );
+        })}
+      </ul>
+      {adding && <AddAccountModal onClose={() => setAdding(false)} />}
+    </div>
+  );
+}
diff --git a/app/src/components/marketplace/AddAccountModal.test.tsx b/app/src/components/marketplace/AddAccountModal.test.tsx
new file mode 100644
index 0000000..a00e4a0
--- /dev/null
+++ b/app/src/components/marketplace/AddAccountModal.test.tsx
@@ -0,0 +1,77 @@
+import { describe, it, expect, vi, beforeEach } from "vitest";
+import { fireEvent, render, screen, waitFor } from "@testing-library/react";
+import { useAppState } from "../../store/appState";
+import type { Project } from "../../lib/types";
+
+const marketplaceGhHostAvailable = vi.fn();
+const addMarketplaceGhHostAccount = vi.fn();
+const addMarketplaceTokenAccount = vi.fn();
+const getSettings = vi.fn();
+vi.mock("../../lib/tauri-commands", () => ({
+  marketplaceGhHostAvailable: () => marketplaceGhHostAvailable(),
+  addMarketplaceGhHostAccount: (...a: unknown[]) => addMarketplaceGhHostAccount(...a),
+  addMarketplaceTokenAccount: (...a: unknown[]) => addMarketplaceTokenAccount(...a),
+  getSettings: () => getSettings(),
+}));
+vi.mock("./GhContainerLoginModal", () => ({
+  default: ({ projectId }: { projectId: string }) => <div>container login for {projectId}</div>,
+}));
+
+import AddAccountModal from "./AddAccountModal";
+
+const running = { id: "p1", name: "api", status: "running", container_id: "c1" } as unknown as Project;
+
+describe("AddAccountModal", () => {
+  beforeEach(() => {
+    vi.clearAllMocks();
+    getSettings.mockResolvedValue({ marketplace_accounts: [] });
+    useAppState.setState({ projects: [running], toasts: [] });
+  });
+
+  it("uses host gh when available", async () => {
+    marketplaceGhHostAvailable.mockResolvedValue(true);
+    addMarketplaceGhHostAccount.mockResolvedValue({ id: "a1" });
+    const onClose = vi.fn();
+    render(<AddAccountModal onClose={onClose} />);
+    expect(await screen.findByText(/gh is installed on this computer/)).toBeInTheDocument();
+    fireEvent.change(screen.getByLabelText("Label"), { target: { value: "Personal" } });
+    fireEvent.click(screen.getByRole("button", { name: "Add account" }));
+    await waitFor(() => expect(addMarketplaceGhHostAccount).toHaveBeenCalledWith("Personal", "github.com"));
+    await waitFor(() => expect(onClose).toHaveBeenCalled());
+  });
+
+  it("falls back to gh in a running container", async () => {
+    marketplaceGhHostAvailable.mockResolvedValue(false);
+    render(<AddAccountModal onClose={vi.fn()} />);
+    expect(await screen.findByLabelText("Run gh in")).toBeInTheDocument();
+    fireEvent.change(screen.getByLabelText("Label"), { target: { value: "Work" } });
+    fireEvent.click(screen.getByRole("button", { name: "Sign in" }));
+    expect(screen.getByText("container login for p1")).toBeInTheDocument();
+  });
+
+  it("adds a token account for any host", async () => {
+    marketplaceGhHostAvailable.mockResolvedValue(false);
+    addMarketplaceTokenAccount.mockResolvedValue({ id: "a2" });
+    render(<AddAccountModal onClose={vi.fn()} />);
+    fireEvent.click(await screen.findByRole("radio", { name: "Access token" }));
+    fireEvent.change(screen.getByLabelText("Label"), { target: { value: "Gitea" } });
+    fireEvent.change(screen.getByLabelText("Host"), { target: { value: "repo.anhonesthost.net" } });
+    fireEvent.change(screen.getByLabelText("Token"), { target: { value: "test-token-not-real" } });
+    fireEvent.click(screen.getByRole("button", { name: "Add account" }));
+    await waitFor(() =>
+      expect(addMarketplaceTokenAccount).toHaveBeenCalledWith("Gitea", "repo.anhonesthost.net", "test-token-not-real"),
+    );
+  });
+
+  it("shows a validation error from the backend", async () => {
+    marketplaceGhHostAvailable.mockResolvedValue(false);
+    addMarketplaceTokenAccount.mockRejectedValue("The token was rejected by repo.anhonesthost.net (HTTP 401)");
+    render(<AddAccountModal onClose={vi.fn()} />);
+    fireEvent.click(await screen.findByRole("radio", { name: "Access token" }));
+    fireEvent.change(screen.getByLabelText("Label"), { target: { value: "G" } });
+    fireEvent.change(screen.getByLabelText("Host"), { target: { value: "repo.anhonesthost.net" } });
+    fireEvent.change(screen.getByLabelText("Token"), { target: { value: "test-token-not-real" } });
+    fireEvent.click(screen.getByRole("button", { name: "Add account" }));
+    expect(await screen.findByText(/HTTP 401/)).toBeInTheDocument();
+  });
+});
diff --git a/app/src/components/marketplace/AddAccountModal.tsx b/app/src/components/marketplace/AddAccountModal.tsx
new file mode 100644
index 0000000..efcf76e
--- /dev/null
+++ b/app/src/components/marketplace/AddAccountModal.tsx
@@ -0,0 +1,190 @@
+import { useEffect, useState } from "react";
+import Modal from "../ui/Modal";
+import Button from "../ui/Button";
+import SegmentedControl from "../ui/SegmentedControl";
+import Field, { inputClass, selectClass } from "../ui/Field";
+import {
+  addMarketplaceGhHostAccount,
+  addMarketplaceTokenAccount,
+  getSettings,
+  marketplaceGhHostAvailable,
+} from "../../lib/tauri-commands";
+import { useAppState } from "../../store/appState";
+import GhContainerLoginModal from "./GhContainerLoginModal";
+
+type Method = "gh" | "token";
+
+interface Props {
+  onClose: () => void;
+}
+
+export default function AddAccountModal({ onClose }: Props) {
+  const projects = useAppState((s) => s.projects);
+  const setAppSettings = useAppState((s) => s.setAppSettings);
+  const runnable = projects.filter((p) => p.status === "running" && p.container_id);
+
+  const [method, setMethod] = useState<Method>("gh");
+  const [hostGh, setHostGh] = useState<boolean | null>(null);
+  const [label, setLabel] = useState("");
+  const [host, setHost] = useState("github.com");
+  const [token, setToken] = useState("");
+  const [projectId, setProjectId] = useState(runnable[0]?.id ?? "");
+  const [busy, setBusy] = useState(false);
+  const [error, setError] = useState<string | null>(null);
+  const [containerLogin, setContainerLogin] = useState(false);
+
+  useEffect(() => {
+    let cancelled = false;
+    marketplaceGhHostAvailable()
+      .then((v) => {
+        if (!cancelled) setHostGh(v);
+      })
+      .catch(() => {
+        if (!cancelled) setHostGh(false);
+      });
+    return () => {
+      cancelled = true;
+    };
+  }, []);
+
+  const reloadSettings = async () => setAppSettings(await getSettings());
+
+  const finish = async () => {
+    await reloadSettings();
+    onClose();
+  };
+
+  const submit = async () => {
+    setError(null);
+    if (method === "gh" && !hostGh) {
+      setContainerLogin(true);
+      return;
+    }
+    setBusy(true);
+    try {
+      if (method === "gh") {
+        await addMarketplaceGhHostAccount(label.trim(), host.trim());
+      } else {
+        const t = token.trim();
+        setToken("");
+        await addMarketplaceTokenAccount(label.trim(), host.trim(), t);
+      }
+      await finish();
+    } catch (e) {
+      setError(typeof e === "string" ? e : String(e));
+    } finally {
+      setBusy(false);
+    }
+  };
+
+  const hostValid = /^[A-Za-z0-9.-]+(:[0-9]+)?$/.test(host.trim());
+  const needsContainer = method === "gh" && hostGh === false;
+  const canSubmit =
+    !busy &&
+    hostGh !== null &&
+    label.trim() !== "" &&
+    hostValid &&
+    (method === "gh" ? !needsContainer || projectId !== "" : token.trim() !== "");
+
+  if (containerLogin) {
+    const project = runnable.find((p) => p.id === projectId);
+    return (
+      <GhContainerLoginModal
+        label={label.trim()}
+        host={host.trim()}
+        projectId={projectId}
+        projectName={project?.name ?? projectId}
+        onClose={onClose}
+        onDone={() => void finish()}
+      />
+    );
+  }
+
+  return (
+    <Modal
+      title="Add account"
+      description="Accounts let Triple-C read private marketplace repositories. Credentials stay on this computer and never enter containers."
+      widthClassName="w-[36rem]"
+      dismissible={!busy}
+      onClose={onClose}
+      footer={
+        <>
+          <Button size="md" variant="ghost" onClick={onClose} disabled={busy}>
+            Cancel
+          </Button>
+          <Button size="md" variant="primary" onClick={() => void submit()} disabled={!canSubmit}>
+            {needsContainer ? "Sign in" : busy ? "Checking…" : "Add account"}
+          </Button>
+        </>
+      }
+    >
+      <div className="space-y-3">
+        <SegmentedControl<Method>
+          label="Sign-in method"
+          value={method}
+          onChange={(m) => {
+            setMethod(m);
+            setError(null);
+          }}
+          segments={[
+            { value: "gh", label: "GitHub via gh" },
+            { value: "token", label: "Access token" },
+          ]}
+        />
+        <Field label="Label">
+          {(id) => (
+            <input id={id} value={label} onChange={(e) => setLabel(e.target.value)} className={inputClass} placeholder="Work GitHub" />
+          )}
+        </Field>
+        <Field label="Host" hint={hostValid ? undefined : "Host name only, e.g. github.com or repo.example.com"}>
+          {(id) => <input id={id} value={host} onChange={(e) => setHost(e.target.value)} className={inputClass} />}
+        </Field>
+        {method === "gh" && hostGh === true && (
+          <p className="text-xs text-[var(--text-secondary)]">
+            gh is installed on this computer. Triple-C asks it for a token each time it fetches, so signing out of gh
+            also signs this account out. If gh is not logged in yet, run <code className="font-mono">gh auth login</code> first.
+          </p>
+        )}
+        {needsContainer &&
+          (runnable.length === 0 ? (
+            <p className="text-xs text-[var(--warning)]">
+              gh is not installed on this computer. Start a project so gh can run in its container, or use an access token.
+            </p>
+          ) : (
+            <Field
+              label="Run gh in"
+              hint="gh is not installed on this computer, so the sign-in runs in this container. The token is kept in your OS keychain, not in the container."
+            >
+              {(id) => (
+                <select id={id} value={projectId} onChange={(e) => setProjectId(e.target.value)} className={selectClass}>
+                  {runnable.map((p) => (
+                    <option key={p.id} value={p.id}>
+                      {p.name}
+                    </option>
+                  ))}
+                </select>
+              )}
+            </Field>
+          ))}
+        {method === "token" && (
+          <Field
+            label="Token"
+            hint="A personal access token with read access to the repository. For GitHub SSO orgs, authorise the token for the org."
+          >
+            {(id) => (
+              <input
+                id={id}
+                type="password"
+                autoComplete="off"
+                value={token}
+                onChange={(e) => setToken(e.target.value)}
+                className={inputClass}
+              />
+            )}
+          </Field>
+        )}
+        {error && <p role="alert" className="text-xs text-[var(--error)] whitespace-pre-wrap">{error}</p>}
+      </div>
+    </Modal>
+  );
+}
diff --git a/app/src/components/marketplace/AddMarketplaceModal.test.tsx b/app/src/components/marketplace/AddMarketplaceModal.test.tsx
new file mode 100644
index 0000000..58002a9
--- /dev/null
+++ b/app/src/components/marketplace/AddMarketplaceModal.test.tsx
@@ -0,0 +1,54 @@
+import { describe, it, expect, vi, beforeEach } from "vitest";
+import { fireEvent, render, screen, waitFor } from "@testing-library/react";
+import { useAppState } from "../../store/appState";
+import type { AppSettings } from "../../lib/types";
+
+const addMarketplace = vi.fn();
+vi.mock("../../lib/tauri-commands", () => ({
+  addMarketplace: (...a: unknown[]) => addMarketplace(...a),
+}));
+
+import AddMarketplaceModal from "./AddMarketplaceModal";
+
+describe("AddMarketplaceModal", () => {
+  beforeEach(() => {
+    vi.clearAllMocks();
+    useAppState.setState({
+      appSettings: {
+        marketplace_accounts: [{ id: "acc1", label: "Work", host: "github.com", method: "token", username: "me" }],
+        marketplaces: [],
+        global_marketplace_installs: [],
+      } as unknown as AppSettings,
+    });
+  });
+
+  it("submits name, url, branch and account", async () => {
+    const onAdded = vi.fn();
+    addMarketplace.mockResolvedValue({ marketplace_id: "m1", head_commit: null, fetched_at: null, fetch_error: null, items: [] });
+    render(<AddMarketplaceModal onClose={vi.fn()} onAdded={onAdded} />);
+    fireEvent.change(screen.getByLabelText("Name"), { target: { value: "Starter" } });
+    fireEvent.change(screen.getByLabelText("Repository URL"), { target: { value: "https://github.com/shadowdao/triple-c-marketplace.git" } });
+    fireEvent.change(screen.getByLabelText("Branch"), { target: { value: "" } });
+    fireEvent.change(screen.getByLabelText("Account"), { target: { value: "acc1" } });
+    fireEvent.click(screen.getByRole("button", { name: "Add marketplace" }));
+    await waitFor(() => expect(onAdded).toHaveBeenCalled());
+    expect(addMarketplace).toHaveBeenCalledWith("Starter", "https://github.com/shadowdao/triple-c-marketplace.git", null, "acc1");
+  });
+
+  it("rejects non-https URLs before calling the backend", () => {
+    render(<AddMarketplaceModal onClose={vi.fn()} onAdded={vi.fn()} />);
+    fireEvent.change(screen.getByLabelText("Name"), { target: { value: "x" } });
+    fireEvent.change(screen.getByLabelText("Repository URL"), { target: { value: "git@github.com:a/b.git" } });
+    expect(screen.getByRole("button", { name: "Add marketplace" })).toBeDisabled();
+    expect(screen.getByText(/must start with https:\/\//)).toBeInTheDocument();
+  });
+
+  it("shows the backend error and stays open", async () => {
+    addMarketplace.mockRejectedValue("Work cannot read this repository (HTTP 404)");
+    render(<AddMarketplaceModal onClose={vi.fn()} onAdded={vi.fn()} />);
+    fireEvent.change(screen.getByLabelText("Name"), { target: { value: "x" } });
+    fireEvent.change(screen.getByLabelText("Repository URL"), { target: { value: "https://github.com/a/b.git" } });
+    fireEvent.click(screen.getByRole("button", { name: "Add marketplace" }));
+    expect(await screen.findByText(/HTTP 404/)).toBeInTheDocument();
+  });
+});
diff --git a/app/src/components/marketplace/AddMarketplaceModal.tsx b/app/src/components/marketplace/AddMarketplaceModal.tsx
new file mode 100644
index 0000000..a795307
--- /dev/null
+++ b/app/src/components/marketplace/AddMarketplaceModal.tsx
@@ -0,0 +1,104 @@
+import { useState } from "react";
+import Modal from "../ui/Modal";
+import Button from "../ui/Button";
+import Field, { inputClass, selectClass } from "../ui/Field";
+import { addMarketplace } from "../../lib/tauri-commands";
+import { useAppState } from "../../store/appState";
+import type { MarketplaceSnapshot } from "../../lib/types";
+
+interface Props {
+  onClose: () => void;
+  onAdded: (snapshot: MarketplaceSnapshot) => void;
+}
+
+export default function AddMarketplaceModal({ onClose, onAdded }: Props) {
+  const accounts = useAppState((s) => s.appSettings?.marketplace_accounts ?? []);
+  const [name, setName] = useState("");
+  const [url, setUrl] = useState("");
+  const [branch, setBranch] = useState("");
+  const [accountId, setAccountId] = useState("");
+  const [busy, setBusy] = useState(false);
+  const [error, setError] = useState<string | null>(null);
+
+  const trimmedUrl = url.trim();
+  const urlProblem =
+    trimmedUrl !== "" && !trimmedUrl.startsWith("https://")
+      ? "The repository URL must start with https:// (SSH URLs are not supported)."
+      : null;
+  const canSubmit = name.trim() !== "" && trimmedUrl !== "" && !urlProblem && !busy;
+
+  const submit = async () => {
+    setBusy(true);
+    setError(null);
+    try {
+      const snap = await addMarketplace(
+        name.trim(),
+        trimmedUrl,
+        branch.trim() === "" ? null : branch.trim(),
+        accountId === "" ? null : accountId,
+      );
+      onAdded(snap);
+      onClose();
+    } catch (e) {
+      setError(typeof e === "string" ? e : String(e));
+    } finally {
+      setBusy(false);
+    }
+  };
+
+  return (
+    <Modal
+      title="Add marketplace"
+      description="Triple-C fetches the repository now to check it can be read. Nothing is saved if that fails."
+      widthClassName="w-[36rem]"
+      dismissible={!busy}
+      onClose={onClose}
+      footer={
+        <>
+          <Button size="md" variant="ghost" onClick={onClose} disabled={busy}>
+            Cancel
+          </Button>
+          <Button size="md" variant="primary" onClick={() => void submit()} disabled={!canSubmit}>
+            {busy ? "Checking…" : "Add marketplace"}
+          </Button>
+        </>
+      }
+    >
+      <div className="space-y-3">
+        <Field label="Name">
+          {(id) => (
+            <input id={id} value={name} onChange={(e) => setName(e.target.value)} className={inputClass} placeholder="Team marketplace" />
+          )}
+        </Field>
+        <Field label="Repository URL" hint={urlProblem ?? "HTTPS clone URL, e.g. https://github.com/owner/repo.git"}>
+          {(id) => (
+            <input id={id} value={url} onChange={(e) => setUrl(e.target.value)} className={inputClass} placeholder="https://github.com/owner/repo.git" />
+          )}
+        </Field>
+        <Field label="Branch" hint="Leave empty to use the repository's default branch.">
+          {(id) => (
+            <input id={id} value={branch} onChange={(e) => setBranch(e.target.value)} className={inputClass} placeholder="main" />
+          )}
+        </Field>
+        <Field label="Account" hint="Needed for private repositories. Add accounts on the Accounts tab.">
+          {(id) => (
+            <select id={id} value={accountId} onChange={(e) => setAccountId(e.target.value)} className={selectClass}>
+              <option value="">None (public repository)</option>
+              {accounts.map((a) => (
+                <option key={a.id} value={a.id}>
+                  {a.label} — {a.host}
+                  {a.username ? ` (${a.username})` : ""}
+                </option>
+              ))}
+            </select>
+          )}
+        </Field>
+        {error && (
+          <p role="alert" className="text-xs text-[var(--error)] whitespace-pre-wrap leading-snug">
+            {error}
+          </p>
+        )}
+      </div>
+    </Modal>
+  );
+}
diff --git a/app/src/components/marketplace/BrowsePane.test.tsx b/app/src/components/marketplace/BrowsePane.test.tsx
new file mode 100644
index 0000000..4c74e50
--- /dev/null
+++ b/app/src/components/marketplace/BrowsePane.test.tsx
@@ -0,0 +1,114 @@
+import { describe, it, expect, vi, beforeEach } from "vitest";
+import { fireEvent, render, screen } from "@testing-library/react";
+import { useAppState } from "../../store/appState";
+import type { AppSettings, CatalogItem, MarketplaceSnapshot } from "../../lib/types";
+import type { MarketplaceApi } from "../../hooks/useMarketplace";
+
+vi.mock("./InstallControls", () => ({ default: () => <div>install controls</div> }));
+vi.mock("./AddMarketplaceModal", () => ({ default: () => <div>add modal</div> }));
+
+import BrowsePane from "./BrowsePane";
+
+const it_ = (kind: CatalogItem["kind"], key: string, patch: Partial<CatalogItem> = {}): CatalogItem => ({
+  kind,
+  key,
+  name: key,
+  description: `${key} description`,
+  path: key,
+  invalid: null,
+  hook_commands: [],
+  preview: `${key} preview body`,
+  ...patch,
+});
+
+const snapshot: MarketplaceSnapshot = {
+  marketplace_id: "m1",
+  head_commit: "a".repeat(40),
+  fetched_at: "2026-09-27T12:00:00Z",
+  fetch_error: "network unreachable",
+  items: [it_("agent", "code-reviewer"), it_("hook", "notify-on-stop"), it_("skill", "broken", { invalid: "SKILL.md missing" })],
+};
+
+function api(patch: Partial<MarketplaceApi> = {}): MarketplaceApi {
+  return {
+    snapshots: [snapshot],
+    updates: [],
+    loading: false,
+    refreshing: [],
+    load: vi.fn(),
+    refresh: vi.fn(),
+    reloadState: vi.fn(),
+    install: vi.fn(),
+    uninstall: vi.fn(),
+    setDisabled: vi.fn(),
+    update: vi.fn(),
+    forget: vi.fn(),
+    remove: vi.fn(async () => true),
+    ...patch,
+  };
+}
+
+describe("BrowsePane", () => {
+  beforeEach(() => {
+    useAppState.setState({
+      appSettings: {
+        marketplaces: [{ id: "m1", name: "Starter", url: "https://github.com/s/m.git", branch: null, account_id: null }],
+        marketplace_accounts: [],
+        global_marketplace_installs: [],
+      } as unknown as AppSettings,
+      projects: [],
+      marketplaceFilterProjectId: null,
+    });
+  });
+
+  it("lists items, filters by kind and search, and shows detail", () => {
+    render(<BrowsePane mp={api()} />);
+    expect(screen.getByText("network unreachable")).toBeInTheDocument();
+    expect(screen.getByRole("button", { name: /code-reviewer/ })).toBeInTheDocument();
+    expect(screen.getByRole("button", { name: /notify-on-stop/ })).toBeInTheDocument();
+
+    fireEvent.click(screen.getByRole("radio", { name: "Hooks" }));
+    expect(screen.queryByRole("button", { name: /code-reviewer/ })).not.toBeInTheDocument();
+
+    fireEvent.click(screen.getByRole("radio", { name: "All" }));
+    fireEvent.change(screen.getByLabelText("Search items"), { target: { value: "review" } });
+    expect(screen.queryByRole("button", { name: /notify-on-stop/ })).not.toBeInTheDocument();
+
+    fireEvent.click(screen.getByRole("button", { name: /code-reviewer/ }));
+    expect(screen.getByText("code-reviewer preview body")).toBeInTheDocument();
+    expect(screen.getByText("install controls")).toBeInTheDocument();
+  });
+
+  it("shows why an item is invalid", () => {
+    render(<BrowsePane mp={api()} />);
+    fireEvent.click(screen.getByRole("button", { name: /broken/ }));
+    expect(screen.getByText("SKILL.md missing")).toBeInTheDocument();
+  });
+
+  it("refreshes one marketplace", () => {
+    const mp = api();
+    render(<BrowsePane mp={mp} />);
+    fireEvent.click(screen.getByRole("button", { name: "Refresh Starter" }));
+    expect(mp.refresh).toHaveBeenCalledWith("m1");
+  });
+
+  it("offers Add when there are no marketplaces", () => {
+    useAppState.setState({
+      appSettings: { marketplaces: [], marketplace_accounts: [], global_marketplace_installs: [] } as unknown as AppSettings,
+    });
+    render(<BrowsePane mp={api({ snapshots: [] })} />);
+    fireEvent.click(screen.getByRole("button", { name: "Add marketplace" }));
+    expect(screen.getByText("add modal")).toBeInTheDocument();
+  });
+
+  it("confirms before removing a marketplace (F6)", () => {
+    const mp = api();
+    render(<BrowsePane mp={mp} />);
+    fireEvent.click(screen.getByRole("button", { name: "Remove Starter" }));
+    expect(screen.getByText(/Source removed/)).toBeInTheDocument();
+    expect(screen.getByText(/Forget/)).toBeInTheDocument();
+    expect(mp.remove).not.toHaveBeenCalled();
+    fireEvent.click(screen.getByRole("button", { name: "Remove marketplace" }));
+    expect(mp.remove).toHaveBeenCalledWith("m1");
+  });
+});
diff --git a/app/src/components/marketplace/BrowsePane.tsx b/app/src/components/marketplace/BrowsePane.tsx
new file mode 100644
index 0000000..08bf9ec
--- /dev/null
+++ b/app/src/components/marketplace/BrowsePane.tsx
@@ -0,0 +1,248 @@
+import { useMemo, useState } from "react";
+import type { MarketplaceApi } from "../../hooks/useMarketplace";
+import { useAppState } from "../../store/appState";
+import { KIND_LABELS, KIND_ORDER, itemRefKey } from "../../lib/marketplace";
+import { updateMarketplace } from "../../lib/tauri-commands";
+import type { CatalogItem, ItemKind, Marketplace } from "../../lib/types";
+import Button from "../ui/Button";
+import Modal from "../ui/Modal";
+import SegmentedControl from "../ui/SegmentedControl";
+import { inputClass, selectClass } from "../ui/Field";
+import AddMarketplaceModal from "./AddMarketplaceModal";
+import ItemDetail from "./ItemDetail";
+
+type KindFilter = ItemKind | "all";
+
+const when = (iso: string | null) => (iso ? new Date(iso).toLocaleString() : "never");
+
+export default function BrowsePane({ mp }: { mp: MarketplaceApi }) {
+  const marketplaces = useAppState((s) => s.appSettings?.marketplaces ?? []);
+  const accounts = useAppState((s) => s.appSettings?.marketplace_accounts ?? []);
+  const globalInstalls = useAppState((s) => s.appSettings?.global_marketplace_installs ?? []);
+  const projects = useAppState((s) => s.projects);
+  const filterId = useAppState((s) => s.marketplaceFilterProjectId);
+  const setFilterId = useAppState((s) => s.setMarketplaceFilterProjectId);
+  const [kind, setKind] = useState<KindFilter>("all");
+  const [query, setQuery] = useState("");
+  const [selected, setSelected] = useState<{ marketplaceId: string; item: CatalogItem } | null>(null);
+  const [adding, setAdding] = useState(false);
+  const [removing, setRemoving] = useState<Marketplace | null>(null);
+
+  const rows = useMemo(() => {
+    const q = query.trim().toLowerCase();
+    return mp.snapshots.flatMap((snap) =>
+      snap.items
+        .filter((i) => kind === "all" || i.kind === kind)
+        .filter((i) => q === "" || `${i.name} ${i.key} ${i.description}`.toLowerCase().includes(q))
+        .sort((a, b) => KIND_ORDER.indexOf(a.kind) - KIND_ORDER.indexOf(b.kind) || a.name.localeCompare(b.name))
+        .map((item) => ({ marketplaceId: snap.marketplace_id, item })),
+    );
+  }, [mp.snapshots, kind, query]);
+
+  const nameOf = (id: string) => marketplaces.find((m) => m.id === id)?.name ?? id;
+
+  const changeAccount = async (m: Marketplace, accountId: string | null) => {
+    await updateMarketplace({ ...m, account_id: accountId });
+    await mp.reloadState();
+  };
+
+  /** Global + every project's installs of this marketplace, for the removal warning. */
+  const installCountFor = (marketplaceId: string) => {
+    const global = globalInstalls.filter((i) => i.marketplace_id === marketplaceId).length;
+    const perProject = projects.reduce(
+      (sum, p) => sum + p.marketplace_installs.filter((i) => i.marketplace_id === marketplaceId).length,
+      0,
+    );
+    return global + perProject;
+  };
+
+  return (
+    <div className="flex h-full min-h-0">
+      <aside className="w-64 flex-shrink-0 border-r border-[var(--border-color)] p-3 space-y-3 overflow-auto">
+        <div className="flex items-center justify-between">
+          <h2 className="text-xs font-medium">Marketplaces</h2>
+          <Button size="sm" variant="secondary" onClick={() => setAdding(true)}>
+            Add marketplace
+          </Button>
+        </div>
+        {marketplaces.length === 0 && (
+          <p className="text-xs text-[var(--text-secondary)]">No marketplaces yet. Add a git repository to browse its items.</p>
+        )}
+        {marketplaces.map((m) => {
+          const snap = mp.snapshots.find((s) => s.marketplace_id === m.id);
+          const refreshing = mp.refreshing.includes(m.id);
+          return (
+            <div key={m.id} className="space-y-1 text-xs">
+              <div className="flex items-center justify-between gap-2">
+                <span className="font-medium truncate" title={m.url}>
+                  {m.name}
+                </span>
+                <div className="flex items-center gap-1 flex-shrink-0">
+                  <Button
+                    size="sm"
+                    variant="ghost"
+                    aria-label={`Refresh ${m.name}`}
+                    disabled={refreshing}
+                    onClick={() => void mp.refresh(m.id)}
+                  >
+                    {refreshing ? "…" : "↻"}
+                  </Button>
+                  <Button
+                    size="sm"
+                    variant="ghost"
+                    aria-label={`Remove ${m.name}`}
+                    onClick={() => setRemoving(m)}
+                  >
+                    Remove
+                  </Button>
+                </div>
+              </div>
+              {accounts.length > 0 ? (
+                <label className="flex items-center gap-1 text-[var(--text-secondary)]">
+                  <span>Account</span>
+                  <select
+                    aria-label={`Account for ${m.name}`}
+                    value={m.account_id ?? ""}
+                    onChange={(e) => void changeAccount(m, e.target.value === "" ? null : e.target.value)}
+                    className={selectClass}
+                  >
+                    <option value="">None (public)</option>
+                    {accounts.map((a) => (
+                      <option key={a.id} value={a.id}>
+                        {a.label}
+                      </option>
+                    ))}
+                  </select>
+                </label>
+              ) : (
+                <p className="text-[var(--text-secondary)]">No account (public repository)</p>
+              )}
+              <p className="text-[var(--text-secondary)]">Last fetched {when(snap?.fetched_at ?? null)}</p>
+              {snap?.fetch_error && (
+                <p className="text-[var(--error)] whitespace-pre-wrap leading-snug">{snap.fetch_error}</p>
+              )}
+            </div>
+          );
+        })}
+        {projects.length > 0 && (
+          <label className="block text-xs space-y-1">
+            <span className="text-[var(--text-secondary)]">Show install state for</span>
+            <select
+              value={filterId ?? ""}
+              onChange={(e) => setFilterId(e.target.value === "" ? null : e.target.value)}
+              className={selectClass}
+            >
+              <option value="">All projects</option>
+              {projects.map((p) => (
+                <option key={p.id} value={p.id}>
+                  {p.name}
+                </option>
+              ))}
+            </select>
+          </label>
+        )}
+      </aside>
+
+      <section className="w-80 flex-shrink-0 border-r border-[var(--border-color)] p-3 space-y-2 overflow-auto">
+        <SegmentedControl<KindFilter>
+          label="Item kind"
+          value={kind}
+          onChange={setKind}
+          segments={[
+            { value: "all", label: "All" },
+            ...KIND_ORDER.map((k) => ({ value: k as KindFilter, label: KIND_LABELS[k] })),
+          ]}
+        />
+        <input
+          aria-label="Search items"
+          value={query}
+          onChange={(e) => setQuery(e.target.value)}
+          placeholder="Search"
+          className={inputClass}
+        />
+        <ul className="space-y-1">
+          {rows.map(({ marketplaceId, item }) => {
+            const key = itemRefKey({ marketplace_id: marketplaceId, kind: item.kind, key: item.key });
+            const isSel =
+              selected?.marketplaceId === marketplaceId &&
+              selected.item.kind === item.kind &&
+              selected.item.key === item.key;
+            return (
+              <li key={key}>
+                <button
+                  type="button"
+                  onClick={() => setSelected({ marketplaceId, item })}
+                  className={`w-full text-left px-2 py-1.5 rounded-[var(--radius-control)] text-xs ${
+                    isSel ? "bg-[var(--bg-tertiary)]" : "hover:bg-[var(--bg-tertiary)]"
+                  }`}
+                >
+                  <span className="font-medium">{item.name}</span>
+                  <span className="ml-1 text-[var(--text-secondary)]">{KIND_LABELS[item.kind].replace(/s$/, "").toLowerCase()}</span>
+                  {item.invalid && <span className="ml-1 text-[var(--error)]">invalid</span>}
+                  {mp.snapshots.length > 1 && (
+                    <span className="block text-[var(--text-secondary)]">{nameOf(marketplaceId)}</span>
+                  )}
+                  {item.description && (
+                    <span className="block text-[var(--text-secondary)] truncate">{item.description}</span>
+                  )}
+                </button>
+              </li>
+            );
+          })}
+          {rows.length === 0 && mp.snapshots.length > 0 && (
+            <li className="text-xs text-[var(--text-secondary)]">No items match.</li>
+          )}
+        </ul>
+      </section>
+
+      <section className="flex-1 min-w-0 p-4 overflow-auto">
+        {selected ? (
+          <ItemDetail mp={mp} item={selected.item} marketplaceId={selected.marketplaceId} />
+        ) : (
+          <p className="text-xs text-[var(--text-secondary)]">Select an item to see what it contains and install it.</p>
+        )}
+      </section>
+
+      {adding && (
+        <AddMarketplaceModal
+          onClose={() => setAdding(false)}
+          onAdded={() => {
+            void mp.reloadState();
+            void mp.load();
+          }}
+        />
+      )}
+
+      {removing && (
+        <Modal
+          title={`Remove marketplace “${removing.name}”?`}
+          onClose={() => setRemoving(null)}
+          footer={
+            <>
+              <Button size="md" variant="ghost" onClick={() => setRemoving(null)}>
+                Cancel
+              </Button>
+              <Button
+                size="md"
+                variant="danger"
+                onClick={() => {
+                  const id = removing.id;
+                  setRemoving(null);
+                  void mp.remove(id);
+                }}
+              >
+                Remove marketplace
+              </Button>
+            </>
+          }
+        >
+          <p className="text-xs text-[var(--text-secondary)] leading-snug">
+            {installCountFor(removing.id)} install{installCountFor(removing.id) === 1 ? "" : "s"} stay listed as
+            “Source removed” and are removed from containers at their next sync. Use “Forget” on the Installed tab
+            instead if you want to drop them immediately.
+          </p>
+        </Modal>
+      )}
+    </div>
+  );
+}
diff --git a/app/src/components/marketplace/GhContainerLoginModal.test.tsx b/app/src/components/marketplace/GhContainerLoginModal.test.tsx
new file mode 100644
index 0000000..80cc00f
--- /dev/null
+++ b/app/src/components/marketplace/GhContainerLoginModal.test.tsx
@@ -0,0 +1,72 @@
+import { describe, it, expect, vi, beforeEach } from "vitest";
+import { act, fireEvent, render, screen, waitFor } from "@testing-library/react";
+
+const startMarketplaceGhContainerLogin = vi.fn();
+const cancelMarketplaceGhLogin = vi.fn();
+const openUrlExternal = vi.fn();
+vi.mock("../../lib/tauri-commands", () => ({
+  startMarketplaceGhContainerLogin: (...a: unknown[]) => startMarketplaceGhContainerLogin(...a),
+  cancelMarketplaceGhLogin: () => cancelMarketplaceGhLogin(),
+  openUrlExternal: (u: string) => openUrlExternal(u),
+}));
+
+const handlers = new Map<string, (e: { payload: unknown }) => void>();
+vi.mock("@tauri-apps/api/event", () => ({
+  listen: vi.fn(async (name: string, cb: (e: { payload: unknown }) => void) => {
+    handlers.set(name, cb);
+    return vi.fn();
+  }),
+}));
+
+import GhContainerLoginModal from "./GhContainerLoginModal";
+
+describe("GhContainerLoginModal", () => {
+  beforeEach(() => {
+    vi.clearAllMocks();
+    handlers.clear();
+  });
+
+  it("shows the device code, opens the URL, and finishes", async () => {
+    let resolve!: (v: unknown) => void;
+    startMarketplaceGhContainerLogin.mockReturnValue(new Promise((r) => (resolve = r)));
+    const onDone = vi.fn();
+    render(
+      <GhContainerLoginModal label="Work" host="github.com" projectId="p1" projectName="api" onClose={vi.fn()} onDone={onDone} />,
+    );
+    await waitFor(() => expect(handlers.has("marketplace-gh-login-code")).toBe(true));
+    await waitFor(() => expect(startMarketplaceGhContainerLogin).toHaveBeenCalledWith("Work", "github.com", "p1"));
+
+    act(() =>
+      handlers.get("marketplace-gh-login-code")!({
+        payload: { account_id: "unknown-yet", code: "ABCD-1234", url: "https://github.com/login/device" },
+      }),
+    );
+    expect(screen.getByText("ABCD-1234")).toBeInTheDocument();
+    fireEvent.click(screen.getByRole("button", { name: "Open GitHub" }));
+    expect(openUrlExternal).toHaveBeenCalledWith("https://github.com/login/device");
+
+    await act(async () => resolve({ id: "acc9", label: "Work", host: "github.com", method: "gh_container", username: "me" }));
+    await waitFor(() => expect(onDone).toHaveBeenCalled());
+  });
+
+  it("refuses to open a non-GitHub URL from the container", async () => {
+    startMarketplaceGhContainerLogin.mockReturnValue(new Promise(() => {}));
+    render(<GhContainerLoginModal label="W" host="github.com" projectId="p1" projectName="api" onClose={vi.fn()} onDone={vi.fn()} />);
+    await waitFor(() => expect(handlers.has("marketplace-gh-login-code")).toBe(true));
+    act(() =>
+      handlers.get("marketplace-gh-login-code")!({
+        payload: { account_id: "x", code: "ABCD-1234", url: "https://evil.example/login" },
+      }),
+    );
+    expect(screen.queryByRole("button", { name: "Open GitHub" })).not.toBeInTheDocument();
+  });
+
+  it("cancels", async () => {
+    startMarketplaceGhContainerLogin.mockReturnValue(new Promise(() => {}));
+    const onClose = vi.fn();
+    render(<GhContainerLoginModal label="W" host="github.com" projectId="p1" projectName="api" onClose={onClose} onDone={vi.fn()} />);
+    fireEvent.click(await screen.findByRole("button", { name: "Cancel sign-in" }));
+    expect(cancelMarketplaceGhLogin).toHaveBeenCalled();
+    expect(onClose).toHaveBeenCalled();
+  });
+});
diff --git a/app/src/components/marketplace/GhContainerLoginModal.tsx b/app/src/components/marketplace/GhContainerLoginModal.tsx
new file mode 100644
index 0000000..33f9bad
--- /dev/null
+++ b/app/src/components/marketplace/GhContainerLoginModal.tsx
@@ -0,0 +1,158 @@
+import { useEffect, useRef, useState } from "react";
+import { listen, type UnlistenFn } from "@tauri-apps/api/event";
+import Modal from "../ui/Modal";
+import Button from "../ui/Button";
+import StatusIndicator from "../ui/StatusIndicator";
+import {
+  cancelMarketplaceGhLogin,
+  openUrlExternal,
+  startMarketplaceGhContainerLogin,
+} from "../../lib/tauri-commands";
+import type { MarketplaceAccount } from "../../lib/types";
+
+interface Props {
+  label: string;
+  host: string;
+  projectId: string;
+  projectName: string;
+  onClose: () => void;
+  onDone: (account: MarketplaceAccount) => void;
+}
+
+interface CodeEvent {
+  account_id: string;
+  code: string;
+  url: string;
+}
+interface OutputEvent {
+  account_id: string;
+  chunk: string;
+}
+
+const MAX_OUTPUT = 8000;
+
+/** Only open device-login pages on the host being signed in to. */
+function safeDeviceUrl(url: string, host: string): string | null {
+  try {
+    const u = new URL(url);
+    return u.protocol === "https:" && u.hostname === host ? u.toString() : null;
+  } catch {
+    return null;
+  }
+}
+
+/**
+ * Drives `gh auth login --web` inside a running container. The command only
+ * resolves when the login finishes, so the new account's id is unknown while it
+ * runs; the modal accepts every gh-login event while open. The backend allows
+ * one gh login at a time, so there is never another flow's event to confuse.
+ */
+export default function GhContainerLoginModal({ label, host, projectId, projectName, onClose, onDone }: Props) {
+  const [code, setCode] = useState<string | null>(null);
+  const [url, setUrl] = useState<string | null>(null);
+  const [output, setOutput] = useState("");
+  const [error, setError] = useState<string | null>(null);
+  const [running, setRunning] = useState(true);
+  const started = useRef(false);
+
+  useEffect(() => {
+    let cancelled = false;
+    const unlisteners: UnlistenFn[] = [];
+    const register = async <T,>(name: string, handle: (p: T) => void) => {
+      const un = await listen<T>(name, (e) => handle(e.payload));
+      if (cancelled) un();
+      else unlisteners.push(un);
+    };
+
+    void (async () => {
+      await register<CodeEvent>("marketplace-gh-login-code", (p) => {
+        setCode(p.code);
+        setUrl(p.url);
+      });
+      await register<OutputEvent>("marketplace-gh-login-output", (p) =>
+        setOutput((prev) => {
+          const next = prev + p.chunk;
+          return next.length > MAX_OUTPUT ? next.slice(next.length - MAX_OUTPUT) : next;
+        }),
+      );
+      if (cancelled || started.current) return;
+      started.current = true;
+      try {
+        const account = await startMarketplaceGhContainerLogin(label, host, projectId);
+        if (!cancelled) {
+          setRunning(false);
+          onDone(account);
+        }
+      } catch (e) {
+        if (!cancelled) {
+          setRunning(false);
+          setError(typeof e === "string" ? e : String(e));
+        }
+      }
+    })();
+
+    return () => {
+      cancelled = true;
+      for (const un of unlisteners) {
+        try {
+          un();
+        } catch {
+          /* already gone */
+        }
+      }
+    };
+    // Runs once per modal instance; the props do not change while it is open.
+    // eslint-disable-next-line react-hooks/exhaustive-deps
+  }, []);
+
+  const cancel = () => {
+    void cancelMarketplaceGhLogin();
+    onClose();
+  };
+
+  const openable = url ? safeDeviceUrl(url, host) : null;
+
+  return (
+    <Modal
+      title={`Sign in to ${host} with gh`}
+      description={`Running gh auth login in "${projectName}". The sign-in is not kept in that container.`}
+      widthClassName="w-[40rem]"
+      dismissible={!running}
+      onClose={running ? cancel : onClose}
+      footer={
+        running ? (
+          <Button size="md" variant="ghost" onClick={cancel}>
+            Cancel sign-in
+          </Button>
+        ) : (
+          <Button size="md" onClick={onClose}>
+            Close
+          </Button>
+        )
+      }
+    >
+      <div className="space-y-3">
+        {running && !code && <StatusIndicator tone="busy" label="Starting gh…" className="text-xs" />}
+        {code && running && (
+          <div className="space-y-2">
+            <p className="text-xs">Enter this code on the GitHub device page:</p>
+            <p className="font-mono text-lg tracking-widest select-all">{code}</p>
+            {openable ? (
+              <Button size="md" variant="primary" onClick={() => void openUrlExternal(openable)}>
+                Open GitHub
+              </Button>
+            ) : (
+              url && <p className="text-xs text-[var(--error)]">The sign-in URL did not point at {host}; not opening it.</p>
+            )}
+          </div>
+        )}
+        {error && <p role="alert" className="text-xs text-[var(--error)] whitespace-pre-wrap">{error}</p>}
+        {output && (
+          <pre className="max-h-40 overflow-auto p-2 text-[11px] font-mono whitespace-pre-wrap rounded-[var(--radius-control)] bg-[var(--bg-primary)] border border-[var(--border-color)]">
+            {output}
+          </pre>
+        )}
+      </div>
+    </Modal>
+  );
+}
diff --git a/app/src/components/marketplace/HookConfirmModal.tsx b/app/src/components/marketplace/HookConfirmModal.tsx
new file mode 100644
index 0000000..f5f4c6e
--- /dev/null
+++ b/app/src/components/marketplace/HookConfirmModal.tsx
@@ -0,0 +1,45 @@
+import Modal from "../ui/Modal";
+import Button from "../ui/Button";
+import type { CatalogItem } from "../../lib/types";
+
+interface Props {
+  item: CatalogItem;
+  onConfirm: () => void;
+  onCancel: () => void;
+}
+
+/** Hooks run shell commands in every Claude session, so installing one is always confirmed. */
+export default function HookConfirmModal({ item, onConfirm, onCancel }: Props) {
+  return (
+    <Modal
+      title={`Install hook “${item.name}”?`}
+      description="This hook runs the commands below inside the container whenever its event fires."
+      widthClassName="w-[40rem]"
+      onClose={onCancel}
+      footer={
+        <>
+          <Button size="md" variant="ghost" onClick={onCancel}>
+            Cancel
+          </Button>
+          <Button size="md" variant="primary" onClick={onConfirm}>
+            Install hook
+          </Button>
+        </>
+      }
+    >
+      {item.hook_commands.length === 0 ? (
+        <p className="text-xs text-[var(--text-secondary)]">This hook declares no commands.</p>
+      ) : (
+        <ul className="space-y-1">
+          {item.hook_commands.map((c) => (
+            <li key={c}>
+              <code className="block font-mono text-xs break-all px-2 py-1 rounded-[var(--radius-control)] bg-[var(--bg-primary)] border border-[var(--border-color)]">
+                {c}
+              </code>
+            </li>
+          ))}
+        </ul>
+      )}
+    </Modal>
+  );
+}
diff --git a/app/src/components/marketplace/InstallControls.test.tsx b/app/src/components/marketplace/InstallControls.test.tsx
new file mode 100644
index 0000000..73aaee0
--- /dev/null
+++ b/app/src/components/marketplace/InstallControls.test.tsx
@@ -0,0 +1,114 @@
+import { describe, it, expect, vi, beforeEach } from "vitest";
+import { fireEvent, render, screen, within } from "@testing-library/react";
+import InstallControls from "./InstallControls";
+import { useAppState } from "../../store/appState";
+import type { AppSettings, CatalogItem, Project } from "../../lib/types";
+import type { MarketplaceApi } from "../../hooks/useMarketplace";
+
+const C = "c".repeat(40);
+
+function api(): MarketplaceApi {
+  return {
+    snapshots: [],
+    updates: [],
+    loading: false,
+    refreshing: [],
+    load: vi.fn(),
+    refresh: vi.fn(),
+    reloadState: vi.fn(),
+    install: vi.fn(async () => true),
+    uninstall: vi.fn(async () => true),
+    setDisabled: vi.fn(async () => true),
+    update: vi.fn(),
+    forget: vi.fn(),
+    remove: vi.fn(),
+  };
+}
+
+const item = (kind: CatalogItem["kind"], patch: Partial<CatalogItem> = {}): CatalogItem => ({
+  kind,
+  key: "rev",
+  name: "rev",
+  description: "",
+  path: `agents/rev.md`,
+  invalid: null,
+  hook_commands: kind === "hook" ? ["/home/claude/.claude/triple-c/hooks/rev/run.sh"] : [],
+  preview: "",
+  ...patch,
+});
+
+const project = (id: string, patch: Partial<Project> = {}) =>
+  ({ id, name: `proj-${id}`, marketplace_installs: [], marketplace_disabled: [], ...patch }) as unknown as Project;
+
+function seed(globalInstalls: AppSettings["global_marketplace_installs"], projects: Project[]) {
+  useAppState.setState({
+    appSettings: { global_marketplace_installs: globalInstalls, marketplaces: [], marketplace_accounts: [] } as unknown as AppSettings,
+    projects,
+    marketplaceFilterProjectId: null,
+  });
+}
+
+const ref = { marketplace_id: "m1", kind: "agent" as const, key: "rev" };
+
+describe("InstallControls", () => {
+  beforeEach(() => seed([], [project("p1"), project("p2")]));
+
+  it("installs for all projects", () => {
+    const mp = api();
+    render(<InstallControls mp={mp} item={item("agent")} marketplaceId="m1" />);
+    fireEvent.click(screen.getByRole("switch", { name: "All projects" }));
+    expect(mp.install).toHaveBeenCalledWith(ref, { type: "global" });
+  });
+
+  it("installs for one project", () => {
+    const mp = api();
+    render(<InstallControls mp={mp} item={item("agent")} marketplaceId="m1" />);
+    fireEvent.click(screen.getByRole("checkbox", { name: /proj-p2/ }));
+    expect(mp.install).toHaveBeenCalledWith(ref, { type: "project", project_id: "p2" });
+  });
+
+  it("opts a project out of a global install and back in", () => {
+    const mp = api();
+    seed([{ ...ref, commit: C }], [project("p1"), project("p2", { marketplace_disabled: [ref] })]);
+    render(<InstallControls mp={mp} item={item("agent")} marketplaceId="m1" />);
+    const row1 = screen.getByTestId("install-row-p1");
+    expect(within(row1).getByText("Inherited")).toBeInTheDocument();
+    fireEvent.click(within(row1).getByRole("checkbox"));
+    expect(mp.setDisabled).toHaveBeenCalledWith("p1", ref, true);
+    const row2 = screen.getByTestId("install-row-p2");
+    expect(within(row2).getByText("Opted out")).toBeInTheDocument();
+    fireEvent.click(within(row2).getByRole("checkbox"));
+    expect(mp.setDisabled).toHaveBeenCalledWith("p2", ref, false);
+  });
+
+  it("removes a project-only install", () => {
+    const mp = api();
+    seed([], [project("p1", { marketplace_installs: [{ ...ref, commit: C }] })]);
+    render(<InstallControls mp={mp} item={item("agent")} marketplaceId="m1" />);
+    fireEvent.click(screen.getByRole("checkbox", { name: /proj-p1/ }));
+    expect(mp.uninstall).toHaveBeenCalledWith(ref, { type: "project", project_id: "p1" });
+  });
+
+  it("requires confirmation before installing a hook", () => {
+    const mp = api();
+    render(<InstallControls mp={mp} item={item("hook")} marketplaceId="m1" />);
+    fireEvent.click(screen.getByRole("switch", { name: "All projects" }));
+    expect(mp.install).not.toHaveBeenCalled();
+    expect(screen.getByText("/home/claude/.claude/triple-c/hooks/rev/run.sh")).toBeInTheDocument();
+    fireEvent.click(screen.getByRole("button", { name: "Install hook" }));
+    expect(mp.install).toHaveBeenCalledWith({ ...ref, kind: "hook" }, { type: "global" });
+  });
+
+  it("disables everything for an invalid item", () => {
+    render(<InstallControls mp={api()} item={item("agent", { invalid: "bad front matter" })} marketplaceId="m1" />);
+    expect(screen.getByRole("switch", { name: "All projects" })).toBeDisabled();
+    expect(screen.getByRole("checkbox", { name: /proj-p1/ })).toBeDisabled();
+  });
+
+  it("shows only the filtered project when a filter is set", () => {
+    useAppState.setState({ marketplaceFilterProjectId: "p2" });
+    render(<InstallControls mp={api()} item={item("agent")} marketplaceId="m1" />);
+    expect(screen.queryByTestId("install-row-p1")).not.toBeInTheDocument();
+    expect(screen.getByTestId("install-row-p2")).toBeInTheDocument();
+  });
+});
diff --git a/app/src/components/marketplace/InstallControls.tsx b/app/src/components/marketplace/InstallControls.tsx
new file mode 100644
index 0000000..c154dbd
--- /dev/null
+++ b/app/src/components/marketplace/InstallControls.tsx
@@ -0,0 +1,125 @@
+import { useState } from "react";
+import { useAppState } from "../../store/appState";
+import { projectItemState, type ProjectItemState } from "../../lib/marketplace";
+import type { MarketplaceApi } from "../../hooks/useMarketplace";
+import type { CatalogItem, InstallScope, MarketplaceItemRef } from "../../lib/types";
+import Toggle from "../ui/Toggle";
+import HookConfirmModal from "./HookConfirmModal";
+
+const STATE_LABEL: Record<ProjectItemState, string> = {
+  none: "",
+  inherited: "Inherited",
+  opted_out: "Opted out",
+  project: "This project",
+  project_pinned_differently: "Pinned to a different commit",
+};
+
+interface Props {
+  mp: MarketplaceApi;
+  item: CatalogItem;
+  marketplaceId: string;
+}
+
+export default function InstallControls({ mp, item, marketplaceId }: Props) {
+  const appSettings = useAppState((s) => s.appSettings);
+  const projects = useAppState((s) => s.projects);
+  const filterId = useAppState((s) => s.marketplaceFilterProjectId);
+  const [pendingHook, setPendingHook] = useState<InstallScope | null>(null);
+  const [busy, setBusy] = useState(false);
+
+  const ref: MarketplaceItemRef = { marketplace_id: marketplaceId, kind: item.kind, key: item.key };
+  const globalInstalls = appSettings?.global_marketplace_installs ?? [];
+  const isGlobal = globalInstalls.some(
+    (g) => g.marketplace_id === marketplaceId && g.kind === item.kind && g.key === item.key,
+  );
+  const disabled = item.invalid !== null || busy;
+  const shown = filterId ? projects.filter((p) => p.id === filterId) : projects;
+
+  const run = async (fn: () => Promise<boolean>) => {
+    setBusy(true);
+    try {
+      await fn();
+    } finally {
+      setBusy(false);
+    }
+  };
+
+  /** Every install goes through here so a hook is always confirmed first. */
+  const install = (scope: InstallScope) => {
+    if (item.kind === "hook") {
+      setPendingHook(scope);
+      return;
+    }
+    void run(() => mp.install(ref, scope));
+  };
+
+  const toggleProject = (projectId: string, state: ProjectItemState) => {
+    const scope: InstallScope = { type: "project", project_id: projectId };
+    switch (state) {
+      case "none":
+        install(scope);
+        break;
+      case "inherited":
+        void run(() => mp.setDisabled(projectId, ref, true));
+        break;
+      case "opted_out":
+        void run(() => mp.setDisabled(projectId, ref, false));
+        break;
+      case "project":
+      case "project_pinned_differently":
+        void run(() => mp.uninstall(ref, scope));
+        break;
+    }
+  };
+
+  return (
+    <div className="space-y-2">
+      <Toggle
+        label="All projects"
+        checked={isGlobal}
+        disabled={disabled}
+        onChange={(v) => (v ? install({ type: "global" }) : void run(() => mp.uninstall(ref, { type: "global" })))}
+      />
+      <ul className="space-y-1">
+        {shown.map((p) => {
+          const state = projectItemState(ref, globalInstalls, p);
+          const checked = state === "inherited" || state === "project" || state === "project_pinned_differently";
+          return (
+            <li
+              key={p.id}
+              data-testid={`install-row-${p.id}`}
+              className="flex items-center justify-between gap-2 text-xs"
+            >
+              <label className="flex items-center gap-2 min-w-0">
+                <input
+                  type="checkbox"
+                  checked={checked}
+                  disabled={disabled}
+                  onChange={() => toggleProject(p.id, state)}
+                />
+                <span className="truncate">{p.name}</span>
+              </label>
+              {STATE_LABEL[state] && (
+                <span className="text-[var(--text-secondary)] whitespace-nowrap">{STATE_LABEL[state]}</span>
+              )}
+            </li>
+          );
+        })}
+      </ul>
+      {projects.length === 0 && (
+        <p className="text-xs text-[var(--text-secondary)]">No projects yet — “All projects” also covers projects added later.</p>
+      )}
+      {pendingHook && (
+        <HookConfirmModal
+          item={item}
+          onCancel={() => setPendingHook(null)}
+          onConfirm={() => {
+            const scope = pendingHook;
+            setPendingHook(null);
+            void run(() => mp.install(ref, scope));
+          }}
+        />
+      )}
+    </div>
+  );
+}
diff --git a/app/src/components/marketplace/InstalledPane.test.tsx b/app/src/components/marketplace/InstalledPane.test.tsx
new file mode 100644
index 0000000..6d94921
--- /dev/null
+++ b/app/src/components/marketplace/InstalledPane.test.tsx
@@ -0,0 +1,144 @@
+import { describe, it, expect, vi, beforeEach } from "vitest";
+import { fireEvent, render, screen, waitFor, within } from "@testing-library/react";
+import { useAppState } from "../../store/appState";
+import type { AppSettings, Project } from "../../lib/types";
+import type { MarketplaceApi } from "../../hooks/useMarketplace";
+
+const applyMarketplaceNow = vi.fn();
+vi.mock("../../lib/tauri-commands", () => ({
+  applyMarketplaceNow: (id?: string) => applyMarketplaceNow(id),
+}));
+vi.mock("./UpdateDiffModal", () => ({
+  default: ({ onAccept }: { onAccept: () => Promise<boolean> }) => (
+    <button onClick={() => void onAccept()}>accept diff</button>
+  ),
+}));
+
+import InstalledPane from "./InstalledPane";
+
+const A = "a".repeat(40);
+const B = "b".repeat(40);
+
+function api(patch: Partial<MarketplaceApi> = {}): MarketplaceApi {
+  return {
+    snapshots: [],
+    updates: [],
+    loading: false,
+    refreshing: [],
+    load: vi.fn(),
+    refresh: vi.fn(),
+    reloadState: vi.fn(),
+    install: vi.fn(),
+    uninstall: vi.fn(async () => true),
+    setDisabled: vi.fn(),
+    update: vi.fn(async () => true),
+    forget: vi.fn(async () => true),
+    remove: vi.fn(),
+    ...patch,
+  };
+}
+
+describe("InstalledPane", () => {
+  beforeEach(() => {
+    vi.clearAllMocks();
+    useAppState.setState({
+      toasts: [],
+      appSettings: {
+        marketplaces: [{ id: "m1", name: "Starter", url: "https://x/y.git", branch: null, account_id: null }],
+        marketplace_accounts: [],
+        global_marketplace_installs: [
+          { marketplace_id: "m1", kind: "agent", key: "rev", commit: A },
+          { marketplace_id: "gone", kind: "skill", key: "old", commit: A },
+        ],
+      } as unknown as AppSettings,
+      projects: [
+        {
+          id: "p1",
+          name: "api",
+          status: "running",
+          marketplace_installs: [{ marketplace_id: "m1", kind: "command", key: "cmd", commit: B }],
+          marketplace_disabled: [],
+        },
+      ] as unknown as Project[],
+    });
+  });
+
+  it("lists global and project installs", () => {
+    render(<InstalledPane mp={api()} />);
+    const global = screen.getByTestId("installed-global");
+    expect(within(global).getByText("rev")).toBeInTheDocument();
+    const proj = screen.getByTestId("installed-project-p1");
+    expect(within(proj).getByText("cmd")).toBeInTheDocument();
+  });
+
+  it("badges and accepts an update for the matching install", async () => {
+    const mp = api({
+      updates: [{ item: { marketplace_id: "m1", kind: "agent", key: "rev" }, pinned: A, head: B }],
+    });
+    render(<InstalledPane mp={mp} />);
+    fireEvent.click(screen.getByRole("button", { name: "Review update for rev" }));
+    fireEvent.click(screen.getByRole("button", { name: "accept diff" }));
+    await waitFor(() =>
+      expect(mp.update).toHaveBeenCalledWith({ marketplace_id: "m1", kind: "agent", key: "rev" }, { type: "global" }),
+    );
+  });
+
+  it("marks installs whose marketplace was removed and forgets them", () => {
+    const mp = api();
+    render(<InstalledPane mp={mp} />);
+    expect(screen.getByText("Source removed")).toBeInTheDocument();
+    fireEvent.click(screen.getByRole("button", { name: "Forget installs from removed marketplaces" }));
+    expect(mp.forget).toHaveBeenCalledWith("gone");
+  });
+
+  it("removes a project install", () => {
+    const mp = api();
+    render(<InstalledPane mp={mp} />);
+    fireEvent.click(screen.getByRole("button", { name: "Remove cmd from api" }));
+    // F7: the ref passed to uninstall must be the bare item ref, not the
+    // MarketplaceInstall (which also carries `commit`).
+    expect(mp.uninstall).toHaveBeenCalledWith(
+      { marketplace_id: "m1", kind: "command", key: "cmd" },
+      { type: "project", project_id: "p1" },
+    );
+  });
+
+  it("applies now and summarises the result", async () => {
+    applyMarketplaceNow.mockResolvedValue([
+      { project_id: "p1", report: { installed: ["agent:rev"], updated: [], removed: [], skipped: [], errors: [], finished_at: "" } },
+    ]);
+    render(<InstalledPane mp={api()} />);
+    fireEvent.click(screen.getByRole("button", { name: "Apply now" }));
+    await waitFor(() => expect(applyMarketplaceNow).toHaveBeenCalledWith(undefined));
+    await waitFor(() => expect(useAppState.getState().toasts[0]).toMatchObject({ kind: "success" }));
+    expect(useAppState.getState().toasts[0].message).toContain("1 running project");
+  });
+
+  it("applies now with no running projects and shows an info toast", async () => {
+    applyMarketplaceNow.mockResolvedValue([]);
+    render(<InstalledPane mp={api()} />);
+    fireEvent.click(screen.getByRole("button", { name: "Apply now" }));
+    await waitFor(() => expect(useAppState.getState().toasts[0]).toMatchObject({ kind: "info" }));
+  });
+
+  it("F4: does not toast per-project sync errors from apply now (the event listener owns that)", async () => {
+    applyMarketplaceNow.mockResolvedValue([
+      {
+        project_id: "p1",
+        report: { installed: [], updated: [], removed: [], skipped: [], errors: ["boom"], finished_at: "" },
+      },
+    ]);
+    render(<InstalledPane mp={api()} />);
+    fireEvent.click(screen.getByRole("button", { name: "Apply now" }));
+    await waitFor(() => expect(applyMarketplaceNow).toHaveBeenCalled());
+    await waitFor(() => expect(useAppState.getState().toasts[0]).toMatchObject({ kind: "success" }));
+    expect(useAppState.getState().toasts).toHaveLength(1);
+  });
+
+  it("toasts an error only when the apply-now call itself fails", async () => {
+    applyMarketplaceNow.mockRejectedValue("container unreachable");
+    render(<InstalledPane mp={api()} />);
+    fireEvent.click(screen.getByRole("button", { name: "Apply now" }));
+    await waitFor(() => expect(useAppState.getState().toasts[0]).toMatchObject({ kind: "error" }));
+  });
+});
diff --git a/app/src/components/marketplace/InstalledPane.tsx b/app/src/components/marketplace/InstalledPane.tsx
new file mode 100644
index 0000000..12e39ad
--- /dev/null
+++ b/app/src/components/marketplace/InstalledPane.tsx
@@ -0,0 +1,185 @@
+import { useState } from "react";
+import type { MarketplaceApi } from "../../hooks/useMarketplace";
+import { useAppState } from "../../store/appState";
+import { KIND_LABELS } from "../../lib/marketplace";
+import { applyMarketplaceNow } from "../../lib/tauri-commands";
+import type { InstallScope, ItemUpdate, MarketplaceInstall, MarketplaceItemRef } from "../../lib/types";
+import Button from "../ui/Button";
+import UpdateDiffModal from "./UpdateDiffModal";
+
+function errorText(e: unknown): string {
+  return typeof e === "string" ? e : e instanceof Error ? e.message : String(e);
+}
+
+interface Pending {
+  install: MarketplaceInstall;
+  update: ItemUpdate;
+  scope: InstallScope;
+  scopeLabel: string;
+}
+
+export default function InstalledPane({ mp }: { mp: MarketplaceApi }) {
+  const appSettings = useAppState((s) => s.appSettings);
+  const projects = useAppState((s) => s.projects);
+  const pushToast = useAppState((s) => s.pushToast);
+  const [pending, setPending] = useState<Pending | null>(null);
+  const [applying, setApplying] = useState(false);
+
+  const marketplaces = appSettings?.marketplaces ?? [];
+  const known = new Set(marketplaces.map((m) => m.id));
+  const nameOf = (id: string) => marketplaces.find((m) => m.id === id)?.name ?? id;
+  const globalInstalls = appSettings?.global_marketplace_installs ?? [];
+
+  const updateFor = (i: MarketplaceInstall) =>
+    mp.updates.find(
+      (u) =>
+        u.item.marketplace_id === i.marketplace_id &&
+        u.item.kind === i.kind &&
+        u.item.key === i.key &&
+        u.head !== i.commit,
+    );
+
+  /** Hooks only (spec §3, preflight F8): the rendered commands at head, so the
+   *  diff review shows what a hook will run after the update, not just the
+   *  raw `hook.json` diff. */
+  const hookCommandsFor = (item: MarketplaceItemRef): string[] | undefined => {
+    if (item.kind !== "hook") return undefined;
+    const snap = mp.snapshots.find((s) => s.marketplace_id === item.marketplace_id);
+    return snap?.items.find((it) => it.kind === "hook" && it.key === item.key)?.hook_commands;
+  };
+
+  const removedSources = [
+    ...new Set(
+      [...globalInstalls, ...projects.flatMap((p) => p.marketplace_installs)]
+        .map((i) => i.marketplace_id)
+        .filter((id) => !known.has(id)),
+    ),
+  ];
+
+  const applyNow = async () => {
+    setApplying(true);
+    try {
+      const results = await applyMarketplaceNow(undefined);
+      // F4 (preflight): the backend emits `marketplace-sync-finished` for
+      // every project synced here, and `useMarketplaceSyncToasts` already
+      // toasts any errors/skips from that event. This toast is only the
+      // success/info summary — a second error toast here would double up.
+      if (results.length === 0) {
+        pushToast({ kind: "info", message: "No running projects — changes apply when a project starts." });
+      } else {
+        pushToast({
+          kind: "success",
+          message: `Marketplace applied to ${results.length} running project${results.length === 1 ? "" : "s"}. New Claude sessions will use it.`,
+        });
+      }
+    } catch (e) {
+      pushToast({ kind: "error", message: "Could not apply marketplace changes", detail: errorText(e) });
+    } finally {
+      setApplying(false);
+    }
+  };
+
+  const row = (i: MarketplaceInstall, scope: InstallScope, scopeLabel: string, removeLabel: string) => {
+    const upd = updateFor(i);
+    const gone = !known.has(i.marketplace_id);
+    // F7 (preflight): pass the bare item ref, not the MarketplaceInstall
+    // itself — `commit` is not part of the ref the backend/store expect here.
+    const ref: MarketplaceItemRef = { marketplace_id: i.marketplace_id, kind: i.kind, key: i.key };
+    return (
+      <li key={`${i.marketplace_id}/${i.kind}/${i.key}`} className="flex items-center justify-between gap-2 text-xs py-1">
+        <div className="min-w-0">
+          <span className="font-medium">{i.key}</span>
+          <span className="ml-1 text-[var(--text-secondary)]">
+            {KIND_LABELS[i.kind].replace(/s$/, "").toLowerCase()} · {nameOf(i.marketplace_id)} · {i.commit.slice(0, 8)}
+          </span>
+          {gone && <span className="ml-2 text-[var(--warning)]">Source removed</span>}
+        </div>
+        <div className="flex gap-1 flex-shrink-0">
+          {upd && !gone && (
+            <Button
+              size="sm"
+              variant="secondary"
+              aria-label={`Review update for ${i.key}`}
+              onClick={() => setPending({ install: i, update: upd, scope, scopeLabel })}
+            >
+              Update available
+            </Button>
+          )}
+          <Button size="sm" variant="ghost" aria-label={removeLabel} onClick={() => void mp.uninstall(ref, scope)}>
+            Remove
+          </Button>
+        </div>
+      </li>
+    );
+  };
+
+  return (
+    <div className="p-4 space-y-4 max-w-4xl">
+      <div className="flex items-center justify-between gap-2">
+        <p className="text-xs text-[var(--text-secondary)]">
+          Installs are pinned to a commit. Containers pick up changes on their next start, or now for running ones.
+          Changes apply to new Claude sessions.
+        </p>
+        <Button size="md" variant="primary" disabled={applying} onClick={() => void applyNow()}>
+          {applying ? "Applying…" : "Apply now"}
+        </Button>
+      </div>
+
+      {removedSources.length > 0 && (
+        <div className="rounded-[var(--radius-control)] border border-[var(--warning)]/40 bg-[var(--warning-muted)] p-2 text-xs space-y-1">
+          <p>
+            Some installs come from marketplaces that were removed. They are removed from containers at their next
+            sync.
+          </p>
+          <Button
+            size="sm"
+            variant="secondary"
+            aria-label="Forget installs from removed marketplaces"
+            onClick={() => removedSources.forEach((id) => void mp.forget(id))}
+          >
+            Forget
+          </Button>
+        </div>
+      )}
+
+      <section data-testid="installed-global">
+        <h3 className="text-xs font-medium mb-1">All projects</h3>
+        {globalInstalls.length === 0 ? (
+          <p className="text-xs text-[var(--text-secondary)]">Nothing installed for all projects.</p>
+        ) : (
+          <ul>{globalInstalls.map((i) => row(i, { type: "global" }, "All projects", `Remove ${i.key} from all projects`))}</ul>
+        )}
+      </section>
+
+      {projects.map((p) => (
+        <section key={p.id} data-testid={`installed-project-${p.id}`}>
+          <h3 className="text-xs font-medium mb-1">{p.name}</h3>
+          {p.marketplace_installs.length === 0 ? (
+            <p className="text-xs text-[var(--text-secondary)]">
+              No project-only installs
+              {p.marketplace_disabled.length > 0 ? ` · opted out of ${p.marketplace_disabled.length} global item(s)` : ""}.
+            </p>
+          ) : (
+            <ul>
+              {p.marketplace_installs.map((i) =>
+                row(i, { type: "project", project_id: p.id }, p.name, `Remove ${i.key} from ${p.name}`),
+              )}
+            </ul>
+          )}
+        </section>
+      ))}
+
+      {pending && (
+        <UpdateDiffModal
+          item={pending.update.item}
+          fromCommit={pending.install.commit}
+          toCommit={pending.update.head}
+          scopeLabel={pending.scopeLabel}
+          hookCommands={hookCommandsFor(pending.update.item)}
+          onClose={() => setPending(null)}
+          onAccept={() => mp.update(pending.update.item, pending.scope)}
+        />
+      )}
+    </div>
+  );
+}
diff --git a/app/src/components/marketplace/ItemDetail.tsx b/app/src/components/marketplace/ItemDetail.tsx
new file mode 100644
index 0000000..3a4647e
--- /dev/null
+++ b/app/src/components/marketplace/ItemDetail.tsx
@@ -0,0 +1,56 @@
+import type { CatalogItem } from "../../lib/types";
+import type { MarketplaceApi } from "../../hooks/useMarketplace";
+import { KIND_LABELS } from "../../lib/marketplace";
+import StatusIndicator from "../ui/StatusIndicator";
+import InstallControls from "./InstallControls";
+
+interface Props {
+  mp: MarketplaceApi;
+  item: CatalogItem;
+  marketplaceId: string;
+}
+
+export default function ItemDetail({ mp, item, marketplaceId }: Props) {
+  return (
+    <div className="space-y-3">
+      <div>
+        <p className="text-[10px] uppercase tracking-wide text-[var(--text-secondary)]">
+          {KIND_LABELS[item.kind].replace(/s$/, "")} · <code className="font-mono">{item.path}</code>
+        </p>
+        <h3 className="text-sm font-medium text-[var(--text-primary)]">{item.name}</h3>
+        {item.description && <p className="text-xs text-[var(--text-secondary)] leading-snug">{item.description}</p>}
+      </div>
+      {item.invalid && (
+        <div className="rounded-[var(--radius-control)] border border-[var(--error)]/40 bg-[var(--error-muted)] p-2">
+          <StatusIndicator tone="error" label="Cannot be installed" className="text-xs" />
+          <p className="mt-1 text-xs text-[var(--text-secondary)]">{item.invalid}</p>
+        </div>
+      )}
+      {item.kind === "hook" && item.hook_commands.length > 0 && (
+        <div>
+          <p className="text-xs font-medium mb-1">Commands this hook runs</p>
+          <ul className="space-y-1">
+            {item.hook_commands.map((c) => (
+              <li key={c}>
+                <code className="block font-mono text-xs break-all">{c}</code>
+              </li>
+            ))}
+          </ul>
+        </div>
+      )}
+      {item.preview && (
+        <pre className="max-h-80 overflow-auto p-2 text-xs font-mono whitespace-pre-wrap rounded-[var(--radius-control)] bg-[var(--bg-primary)] border border-[var(--border-color)]">
+          {item.preview}
+        </pre>
+      )}
+      <div>
+        <p className="text-xs font-medium mb-1">Install</p>
+        <InstallControls mp={mp} item={item} marketplaceId={marketplaceId} />
+        <p className="mt-2 text-[11px] text-[var(--text-secondary)]">
+          Running containers pick changes up on their next start or with “Apply now” on the Installed tab. Changes
+          apply to new Claude sessions.
+        </p>
+      </div>
+    </div>
+  );
+}
diff --git a/app/src/components/marketplace/MarketplaceView.test.tsx b/app/src/components/marketplace/MarketplaceView.test.tsx
new file mode 100644
index 0000000..512d955
--- /dev/null
+++ b/app/src/components/marketplace/MarketplaceView.test.tsx
@@ -0,0 +1,45 @@
+import { describe, it, expect, vi, beforeEach } from "vitest";
+import { fireEvent, render, screen, waitFor } from "@testing-library/react";
+
+const load = vi.fn(async () => {});
+vi.mock("../../hooks/useMarketplace", () => ({
+  useMarketplace: () => ({
+    snapshots: [],
+    updates: [],
+    loading: false,
+    refreshing: [],
+    load,
+    refresh: vi.fn(),
+    reloadState: vi.fn(),
+    install: vi.fn(),
+    uninstall: vi.fn(),
+    setDisabled: vi.fn(),
+    update: vi.fn(),
+    forget: vi.fn(),
+    remove: vi.fn(),
+  }),
+}));
+vi.mock("./BrowsePane", () => ({ default: () => <div>browse pane</div> }));
+vi.mock("./InstalledPane", () => ({ default: () => <div>installed pane</div> }));
+vi.mock("./AccountsPane", () => ({ default: () => <div>accounts pane</div> }));
+
+import MarketplaceView from "./MarketplaceView";
+
+describe("MarketplaceView", () => {
+  beforeEach(() => vi.clearAllMocks());
+
+  it("loads with stale refresh when first shown and switches sub-tabs", async () => {
+    render(<MarketplaceView active />);
+    await waitFor(() => expect(load).toHaveBeenCalledWith({ refreshStale: true }));
+    expect(screen.getByText("browse pane")).toBeInTheDocument();
+    fireEvent.click(screen.getByRole("tab", { name: "Installed" }));
+    expect(screen.getByText("installed pane")).toBeInTheDocument();
+    fireEvent.click(screen.getByRole("tab", { name: "Accounts" }));
+    expect(screen.getByText("accounts pane")).toBeInTheDocument();
+  });
+
+  it("does not load while hidden", () => {
+    render(<MarketplaceView active={false} />);
+    expect(load).not.toHaveBeenCalled();
+  });
+});
diff --git a/app/src/components/marketplace/MarketplaceView.tsx b/app/src/components/marketplace/MarketplaceView.tsx
new file mode 100644
index 0000000..b33a080
--- /dev/null
+++ b/app/src/components/marketplace/MarketplaceView.tsx
@@ -0,0 +1,67 @@
+import { useEffect, useRef, useState } from "react";
+import { useMarketplace } from "../../hooks/useMarketplace";
+import BrowsePane from "./BrowsePane";
+import InstalledPane from "./InstalledPane";
+import AccountsPane from "./AccountsPane";
+
+const SUB_TABS = [
+  { id: "browse", label: "Browse" },
+  { id: "installed", label: "Installed" },
+  { id: "accounts", label: "Accounts" },
+] as const;
+
+export type MarketplaceSubTab = (typeof SUB_TABS)[number]["id"];
+
+interface Props {
+  active: boolean;
+}
+
+export default function MarketplaceView({ active }: Props) {
+  const mp = useMarketplace();
+  const [tab, setTab] = useState<MarketplaceSubTab>("browse");
+  const { load } = mp;
+  const wasActive = useRef(false);
+
+  // Load (and refresh stale marketplaces) each time the tab comes to the front.
+  useEffect(() => {
+    if (active && !wasActive.current) void load({ refreshStale: true });
+    wasActive.current = active;
+  }, [active, load]);
+
+  return (
+    <div className={`w-full h-full flex flex-col min-h-0 ${active ? "" : "hidden"}`}>
+      <div
+        role="tablist"
+        aria-label="Marketplace sections"
+        className="flex gap-1 px-3 pt-3 border-b border-[var(--border-color)]"
+      >
+        {SUB_TABS.map((t) => (
+          <button
+            key={t.id}
+            type="button"
+            role="tab"
+            aria-selected={tab === t.id}
+            onClick={() => setTab(t.id)}
+            className={`px-3 py-1.5 text-xs rounded-t-[var(--radius-control)] ${
+              tab === t.id
+                ? "bg-[var(--bg-primary)] text-[var(--text-primary)]"
+                : "text-[var(--text-secondary)] hover:text-[var(--text-primary)]"
+            }`}
+          >
+            {t.label}
+            {t.id === "installed" && mp.updates.length > 0 && (
+              <span className="ml-1.5 px-1 rounded-[4px] text-[10px] bg-[var(--accent-muted)] text-[var(--accent)]">
+                {mp.updates.length}
+              </span>
+            )}
+          </button>
+        ))}
+      </div>
+      <div className="flex-1 min-h-0 overflow-auto">
+        {tab === "browse" && <BrowsePane mp={mp} />}
+        {tab === "installed" && <InstalledPane mp={mp} />}
+        {tab === "accounts" && <AccountsPane mp={mp} />}
+      </div>
+    </div>
+  );
+}
diff --git a/app/src/components/marketplace/UpdateDiffModal.test.tsx b/app/src/components/marketplace/UpdateDiffModal.test.tsx
new file mode 100644
index 0000000..2f74188
--- /dev/null
+++ b/app/src/components/marketplace/UpdateDiffModal.test.tsx
@@ -0,0 +1,58 @@
+import { describe, it, expect, vi, beforeEach } from "vitest";
+import { fireEvent, render, screen, waitFor } from "@testing-library/react";
+
+const marketplaceItemDiff = vi.fn();
+vi.mock("../../lib/tauri-commands", () => ({
+  marketplaceItemDiff: (...a: unknown[]) => marketplaceItemDiff(...a),
+}));
+
+import UpdateDiffModal from "./UpdateDiffModal";
+
+const A = "a".repeat(40);
+const B = "b".repeat(40);
+const item = { marketplace_id: "m1", kind: "hook" as const, key: "notify" };
+
+describe("UpdateDiffModal", () => {
+  beforeEach(() => vi.clearAllMocks());
+
+  it("loads the diff from the install's pin to head and accepts", async () => {
+    marketplaceItemDiff.mockResolvedValue([
+      { path: "notify.sh", change: "modified", unified: "-echo old\n+echo new\n" },
+      { path: "icon.png", change: "added", unified: null },
+    ]);
+    const onAccept = vi.fn(async () => true);
+    render(<UpdateDiffModal item={item} fromCommit={A} toCommit={B} scopeLabel="All projects" onClose={vi.fn()} onAccept={onAccept} />);
+    await waitFor(() => expect(marketplaceItemDiff).toHaveBeenCalledWith(item, A, B));
+    expect(screen.getByText(/\+echo new/)).toBeInTheDocument();
+    expect(screen.getByText("Binary file — no text diff")).toBeInTheDocument();
+    fireEvent.click(screen.getByRole("button", { name: "Update" }));
+    await waitFor(() => expect(onAccept).toHaveBeenCalled());
+  });
+
+  it("shows a load error and keeps Update disabled", async () => {
+    marketplaceItemDiff.mockRejectedValue("commit not in cache");
+    render(<UpdateDiffModal item={item} fromCommit={A} toCommit={B} scopeLabel="p" onClose={vi.fn()} onAccept={vi.fn()} />);
+    expect(await screen.findByText(/commit not in cache/)).toBeInTheDocument();
+    expect(screen.getByRole("button", { name: "Update" })).toBeDisabled();
+  });
+
+  it("shows the rendered commands a hook will run after the update (F8)", async () => {
+    marketplaceItemDiff.mockResolvedValue([]);
+    render(
+      <UpdateDiffModal
+        item={item}
+        fromCommit={A}
+        toCommit={B}
+        scopeLabel="All projects"
+        hookCommands={["/home/claude/.claude/triple-c/hooks/notify/run.sh --new-flag"]}
+        onClose={vi.fn()}
+        onAccept={vi.fn()}
+      />,
+    );
+    await waitFor(() => expect(marketplaceItemDiff).toHaveBeenCalled());
+    expect(screen.getByText("Commands after this update")).toBeInTheDocument();
+    expect(
+      screen.getByText("/home/claude/.claude/triple-c/hooks/notify/run.sh --new-flag"),
+    ).toBeInTheDocument();
+  });
+});
diff --git a/app/src/components/marketplace/UpdateDiffModal.tsx b/app/src/components/marketplace/UpdateDiffModal.tsx
new file mode 100644
index 0000000..a8b569f
--- /dev/null
+++ b/app/src/components/marketplace/UpdateDiffModal.tsx
@@ -0,0 +1,128 @@
+import { useEffect, useState } from "react";
+import Modal from "../ui/Modal";
+import Button from "../ui/Button";
+import { marketplaceItemDiff } from "../../lib/tauri-commands";
+import { formatItemRef } from "../../lib/marketplace";
+import type { FileDiff, MarketplaceItemRef } from "../../lib/types";
+
+interface Props {
+  item: MarketplaceItemRef;
+  fromCommit: string;
+  toCommit: string;
+  scopeLabel: string;
+  /**
+   * Hooks only: the rendered commands the item runs at `toCommit` (head), from
+   * the marketplace snapshot's catalog entry. An update can change what a hook
+   * runs without going back through the install-time confirm list, so this is
+   * shown alongside the file diff — spec §3. Undefined for non-hook items.
+   */
+  hookCommands?: string[];
+  onClose: () => void;
+  /** Resolves true when the update was applied. */
+  onAccept: () => Promise<boolean>;
+}
+
+const CHANGE_LABEL: Record<FileDiff["change"], string> = {
+  added: "added",
+  removed: "removed",
+  modified: "modified",
+};
+
+export default function UpdateDiffModal({
+  item,
+  fromCommit,
+  toCommit,
+  scopeLabel,
+  hookCommands,
+  onClose,
+  onAccept,
+}: Props) {
+  const [diffs, setDiffs] = useState<FileDiff[] | null>(null);
+  const [error, setError] = useState<string | null>(null);
+  const [busy, setBusy] = useState(false);
+
+  useEffect(() => {
+    let cancelled = false;
+    marketplaceItemDiff(item, fromCommit, toCommit)
+      .then((d) => {
+        if (!cancelled) setDiffs(d);
+      })
+      .catch((e) => {
+        if (!cancelled) setError(typeof e === "string" ? e : String(e));
+      });
+    return () => {
+      cancelled = true;
+    };
+  }, [item, fromCommit, toCommit]);
+
+  const accept = async () => {
+    setBusy(true);
+    try {
+      if (await onAccept()) onClose();
+    } finally {
+      setBusy(false);
+    }
+  };
+
+  return (
+    <Modal
+      title={`Update ${formatItemRef(item)}`}
+      description={`${scopeLabel}: ${fromCommit.slice(0, 8)} → ${toCommit.slice(0, 8)}. Review the changes before accepting.`}
+      widthClassName="w-[52rem]"
+      dismissible={!busy}
+      onClose={onClose}
+      footer={
+        <>
+          <Button size="md" variant="ghost" onClick={onClose} disabled={busy}>
+            Cancel
+          </Button>
+          <Button size="md" variant="primary" onClick={() => void accept()} disabled={busy || diffs === null}>
+            Update
+          </Button>
+        </>
+      }
+    >
+      {error && <p role="alert" className="text-xs text-[var(--error)]">{error}</p>}
+      {!error && diffs === null && <p className="text-xs text-[var(--text-secondary)]">Loading changes…</p>}
+      {hookCommands && (
+        <div className="mb-3">
+          <p className="text-xs font-medium mb-1">Commands after this update</p>
+          {hookCommands.length === 0 ? (
+            <p className="text-xs text-[var(--text-secondary)]">This hook declares no commands.</p>
+          ) : (
+            <ul className="space-y-1">
+              {hookCommands.map((c) => (
+                <li key={c}>
+                  <code className="block font-mono text-xs break-all px-2 py-1 rounded-[var(--radius-control)] bg-[var(--bg-primary)] border border-[var(--border-color)]">
+                    {c}
+                  </code>
+                </li>
+              ))}
+            </ul>
+          )}
+        </div>
+      )}
+      {diffs && diffs.length === 0 && (
+        <p className="text-xs text-[var(--text-secondary)]">No file changes (only the catalog entry changed).</p>
+      )}
+      {diffs && diffs.length > 0 && (
+        <div className="space-y-3 max-h-[60vh] overflow-auto">
+          {diffs.map((d) => (
+            <div key={d.path}>
+              <p className="text-xs font-mono mb-1">
+                {d.path} <span className="text-[var(--text-secondary)]">({CHANGE_LABEL[d.change]})</span>
+              </p>
+              {d.unified === null ? (
+                <p className="text-xs text-[var(--text-secondary)]">Binary file — no text diff</p>
+              ) : (
+                <pre className="p-2 text-xs font-mono whitespace-pre overflow-auto rounded-[var(--radius-control)] bg-[var(--bg-primary)] border border-[var(--border-color)]">
+                  {d.unified}
+                </pre>
+              )}
+            </div>
+          ))}
+        </div>
+      )}
+    </Modal>
+  );
+}
diff --git a/app/src/components/projects/home/ConfigTab.tsx b/app/src/components/projects/home/ConfigTab.tsx
index 566e078..037f228 100644
--- a/app/src/components/projects/home/ConfigTab.tsx
+++ b/app/src/components/projects/home/ConfigTab.tsx
@@ -5,6 +5,7 @@ import WorkspaceSection from "./config/WorkspaceSection";
 import ModelSection from "./config/ModelSection";
 import AccessSection from "./config/AccessSection";
 import RuntimeSection from "./config/RuntimeSection";
+import MarketplaceSection from "./config/MarketplaceSection";
 
 interface Props {
   project: Project;
@@ -52,6 +53,7 @@ export default function ConfigTab({ project, save, saveState }: Props) {
         disabled={disabled}
         disabledReason={STOPPED_ONLY}
       />
+      <MarketplaceSection project={project} />
     </div>
   );
 }
diff --git a/app/src/components/projects/home/config/MarketplaceSection.test.tsx b/app/src/components/projects/home/config/MarketplaceSection.test.tsx
new file mode 100644
index 0000000..e623078
--- /dev/null
+++ b/app/src/components/projects/home/config/MarketplaceSection.test.tsx
@@ -0,0 +1,119 @@
+import { describe, it, expect, vi, beforeEach } from "vitest";
+import { fireEvent, render, screen, waitFor, within } from "@testing-library/react";
+import { useAppState, MARKETPLACE_TAB_KEY } from "../../../../store/appState";
+import type { AppSettings, Project } from "../../../../lib/types";
+
+const setGlobalItemDisabled = vi.fn();
+const getMarketplaceSyncReport = vi.fn();
+vi.mock("../../../../lib/tauri-commands", () => ({
+  setGlobalItemDisabled: (...a: unknown[]) => setGlobalItemDisabled(...a),
+  getMarketplaceSyncReport: (id: string) => getMarketplaceSyncReport(id),
+}));
+
+let syncFinishedHandler: ((event: { payload: { project_id: string; report: unknown } }) => void) | null = null;
+const listenMock = vi.fn(async (_name: string, cb: (event: { payload: { project_id: string; report: unknown } }) => void) => {
+  syncFinishedHandler = cb;
+  return vi.fn();
+});
+vi.mock("@tauri-apps/api/event", () => ({
+  listen: (...a: Parameters<typeof listenMock>) => listenMock(...a),
+}));
+
+import MarketplaceSection from "./MarketplaceSection";
+
+const A = "a".repeat(40);
+const project = {
+  id: "p1",
+  name: "api",
+  status: "running",
+  marketplace_installs: [{ marketplace_id: "m1", kind: "command", key: "cmd", commit: A }],
+  marketplace_disabled: [{ marketplace_id: "m1", kind: "hook", key: "noisy" }],
+} as unknown as Project;
+
+describe("MarketplaceSection", () => {
+  beforeEach(() => {
+    vi.clearAllMocks();
+    syncFinishedHandler = null;
+    useAppState.setState({
+      tabOrder: [],
+      activeTabKey: null,
+      projects: [project],
+      toasts: [],
+      appSettings: {
+        marketplaces: [{ id: "m1", name: "Starter", url: "https://x/y.git", branch: null, account_id: null }],
+        marketplace_accounts: [],
+        global_marketplace_installs: [
+          { marketplace_id: "m1", kind: "agent", key: "rev", commit: A },
+          { marketplace_id: "m1", kind: "hook", key: "noisy", commit: A },
+        ],
+      } as unknown as AppSettings,
+    });
+    getMarketplaceSyncReport.mockResolvedValue({
+      installed: ["agent:rev"],
+      updated: [],
+      removed: [],
+      skipped: [{ item: "command:cmd", reason: "a file you created has the same name" }],
+      errors: [],
+      finished_at: "2026-09-27T12:00:00Z",
+    });
+  });
+
+  it("shows effective items with their source and the opted-out global item", async () => {
+    render(<MarketplaceSection project={project} />);
+    const rev = screen.getByTestId("mp-global-agent-rev");
+    expect(within(rev).getByRole("switch")).toBeChecked();
+    const noisy = screen.getByTestId("mp-global-hook-noisy");
+    expect(within(noisy).getByRole("switch")).not.toBeChecked();
+    expect(screen.getByTestId("mp-project-command-cmd")).toHaveTextContent("This project only");
+    expect(await screen.findByText(/a file you created has the same name/)).toBeInTheDocument();
+  });
+
+  it("opts out of a global item", async () => {
+    setGlobalItemDisabled.mockResolvedValue({ ...project, marketplace_disabled: [] });
+    render(<MarketplaceSection project={project} />);
+    fireEvent.click(within(screen.getByTestId("mp-global-agent-rev")).getByRole("switch"));
+    await waitFor(() =>
+      expect(setGlobalItemDisabled).toHaveBeenCalledWith("p1", { marketplace_id: "m1", kind: "agent", key: "rev" }, true),
+    );
+  });
+
+  it("opens the Marketplace filtered to this project", () => {
+    render(<MarketplaceSection project={project} />);
+    fireEvent.click(screen.getByRole("button", { name: "Open in Marketplace" }));
+    expect(useAppState.getState().activeTabKey).toBe(MARKETPLACE_TAB_KEY);
+    expect(useAppState.getState().marketplaceFilterProjectId).toBe("p1");
+  });
+
+  it("refetches the sync report when marketplace-sync-finished fires for this project", async () => {
+    render(<MarketplaceSection project={project} />);
+    await screen.findByText(/a file you created has the same name/);
+    expect(getMarketplaceSyncReport).toHaveBeenCalledTimes(1);
+
+    getMarketplaceSyncReport.mockResolvedValue({
+      installed: [],
+      updated: [],
+      removed: [],
+      skipped: [],
+      errors: ["boom"],
+      finished_at: "2026-09-27T13:00:00Z",
+    });
+
+    expect(syncFinishedHandler).not.toBeNull();
+    syncFinishedHandler?.({ payload: { project_id: "p1", report: {} } });
+
+    await waitFor(() => expect(getMarketplaceSyncReport).toHaveBeenCalledTimes(2));
+    expect(await screen.findByText("boom")).toBeInTheDocument();
+  });
+
+  it("ignores marketplace-sync-finished events for other projects", async () => {
+    render(<MarketplaceSection project={project} />);
+    await screen.findByText(/a file you created has the same name/);
+    expect(getMarketplaceSyncReport).toHaveBeenCalledTimes(1);
+
+    expect(syncFinishedHandler).not.toBeNull();
+    syncFinishedHandler?.({ payload: { project_id: "p2", report: {} } });
+
+    await new Promise((r) => setTimeout(r, 0));
+    expect(getMarketplaceSyncReport).toHaveBeenCalledTimes(1);
+  });
+});
diff --git a/app/src/components/projects/home/config/MarketplaceSection.tsx b/app/src/components/projects/home/config/MarketplaceSection.tsx
new file mode 100644
index 0000000..6c71711
--- /dev/null
+++ b/app/src/components/projects/home/config/MarketplaceSection.tsx
@@ -0,0 +1,171 @@
+import { useEffect, useState } from "react";
+import { listen, type UnlistenFn } from "@tauri-apps/api/event";
+import { ConfigGroup } from "../../../ui/Field";
+import Toggle from "../../../ui/Toggle";
+import Button from "../../../ui/Button";
+import { useAppState } from "../../../../store/appState";
+import { KIND_LABELS } from "../../../../lib/marketplace";
+import { getMarketplaceSyncReport, setGlobalItemDisabled } from "../../../../lib/tauri-commands";
+import type { MarketplaceItemRef, Project, SyncReport } from "../../../../lib/types";
+
+interface Props {
+  project: Project;
+}
+
+interface SyncFinishedEvent {
+  project_id: string;
+  report: SyncReport;
+}
+
+const kindWord = (k: MarketplaceItemRef["kind"]) => KIND_LABELS[k].replace(/s$/, "").toLowerCase();
+const same = (a: MarketplaceItemRef, b: MarketplaceItemRef) =>
+  a.marketplace_id === b.marketplace_id && a.kind === b.kind && a.key === b.key;
+
+export default function MarketplaceSection({ project }: Props) {
+  const appSettings = useAppState((s) => s.appSettings);
+  const openMarketplace = useAppState((s) => s.openMarketplace);
+  const updateProjectInList = useAppState((s) => s.updateProjectInList);
+  const pushToast = useAppState((s) => s.pushToast);
+  const [report, setReport] = useState<SyncReport | null>(null);
+  const [busy, setBusy] = useState<string | null>(null);
+
+  const globalInstalls = appSettings?.global_marketplace_installs ?? [];
+  const nameOf = (id: string) => appSettings?.marketplaces.find((m) => m.id === id)?.name ?? "removed marketplace";
+
+  useEffect(() => {
+    let cancelled = false;
+
+    const fetchReport = () => {
+      getMarketplaceSyncReport(project.id)
+        .then((r) => {
+          if (!cancelled) setReport(r);
+        })
+        .catch(() => {
+          if (!cancelled) setReport(null);
+        });
+    };
+
+    fetchReport();
+
+    // N7 (preflight): a sync also runs outside this component's own actions
+    // (container start, "Apply now" from the Marketplace tab), so without
+    // this the report shown here goes stale as soon as one finishes.
+    let unlisten: UnlistenFn | null = null;
+    listen<SyncFinishedEvent>("marketplace-sync-finished", (event) => {
+      if (event.payload.project_id === project.id) fetchReport();
+    })
+      .then((fn) => {
+        if (cancelled) fn();
+        else unlisten = fn;
+      })
+      .catch(() => {
+        // Not running inside Tauri (e.g. tests) — nothing to listen to.
+      });
+
+    return () => {
+      cancelled = true;
+      unlisten?.();
+    };
+  }, [project.id, project.status]);
+
+  const toggleGlobal = async (ref: MarketplaceItemRef, enabled: boolean) => {
+    const id = `${ref.kind}-${ref.key}`;
+    setBusy(id);
+    try {
+      updateProjectInList(await setGlobalItemDisabled(project.id, ref, !enabled));
+    } catch (e) {
+      pushToast({ kind: "error", message: `Could not change ${ref.key} for “${project.name}”`, detail: String(e) });
+    } finally {
+      setBusy(null);
+    }
+  };
+
+  return (
+    <ConfigGroup
+      title="Marketplace"
+      description="Items this project gets from marketplaces. Changes apply on the next container start or with Apply now, in new Claude sessions."
+    >
+      <div className="space-y-3">
+        {globalInstalls.length > 0 && (
+          <div>
+            <p className="text-xs font-medium mb-1">From “All projects”</p>
+            <ul className="space-y-1">
+              {globalInstalls.map((g) => {
+                const shadowed = project.marketplace_installs.some((p) => same(p, g));
+                const enabled = !project.marketplace_disabled.some((d) => same(d, g));
+                return (
+                  <li
+                    key={`${g.marketplace_id}/${g.kind}/${g.key}`}
+                    data-testid={`mp-global-${g.kind}-${g.key}`}
+                    className="flex items-center justify-between gap-2 text-xs"
+                  >
+                    <span className="min-w-0 truncate">
+                      <span className="font-medium">{g.key}</span>{" "}
+                      <span className="text-[var(--text-secondary)]">
+                        {kindWord(g.kind)} · {nameOf(g.marketplace_id)}
+                        {shadowed ? " · overridden by this project's own install" : ""}
+                      </span>
+                    </span>
+                    <Toggle
+                      label={`Use ${g.key} in ${project.name}`}
+                      checked={enabled}
+                      disabled={busy === `${g.kind}-${g.key}`}
+                      onChange={(v) => void toggleGlobal({ marketplace_id: g.marketplace_id, kind: g.kind, key: g.key }, v)}
+                    />
+                  </li>
+                );
+              })}
+            </ul>
+          </div>
+        )}
+        {project.marketplace_installs.length > 0 && (
+          <div>
+            <p className="text-xs font-medium mb-1">This project only</p>
+            <ul className="space-y-1">
+              {project.marketplace_installs.map((i) => (
+                <li
+                  key={`${i.marketplace_id}/${i.kind}/${i.key}`}
+                  data-testid={`mp-project-${i.kind}-${i.key}`}
+                  className="text-xs"
+                >
+                  <span className="font-medium">{i.key}</span>{" "}
+                  <span className="text-[var(--text-secondary)]">
+                    {kindWord(i.kind)} · {nameOf(i.marketplace_id)} · This project only
+                  </span>
+                </li>
+              ))}
+            </ul>
+          </div>
+        )}
+        {globalInstalls.length === 0 && project.marketplace_installs.length === 0 && (
+          <p className="text-xs text-[var(--text-secondary)]">Nothing installed from a marketplace.</p>
+        )}
+
+        {report && (
+          <div className="text-xs space-y-1">
+            <p className="font-medium">
+              Last sync {report.finished_at ? new Date(report.finished_at).toLocaleString() : ""}
+            </p>
+            <p className="text-[var(--text-secondary)]">
+              {report.installed.length} installed · {report.updated.length} updated · {report.removed.length} removed
+            </p>
+            {report.skipped.map((s) => (
+              <p key={s.item} className="text-[var(--warning)]">
+                Skipped {s.item}: {s.reason}
+              </p>
+            ))}
+            {report.errors.map((e) => (
+              <p key={e} className="text-[var(--error)] whitespace-pre-wrap">
+                {e}
+              </p>
+            ))}
+          </div>
+        )}
+
+        <Button size="sm" variant="secondary" onClick={() => openMarketplace(project.id)}>
+          Open in Marketplace
+        </Button>
+      </div>
+    </ConfigGroup>
+  );
+}
diff --git a/app/src/components/settings/MarketplaceSettings.test.tsx b/app/src/components/settings/MarketplaceSettings.test.tsx
new file mode 100644
index 0000000..f187e4e
--- /dev/null
+++ b/app/src/components/settings/MarketplaceSettings.test.tsx
@@ -0,0 +1,42 @@
+import { describe, it, expect, vi, beforeEach } from "vitest";
+import { fireEvent, render, screen, waitFor } from "@testing-library/react";
+import MarketplaceSettings from "./MarketplaceSettings";
+import { useAppState, MARKETPLACE_TAB_KEY } from "../../store/appState";
+import type { AppSettings } from "../../lib/types";
+
+const listMarketplaceUpdates = vi.fn();
+vi.mock("../../lib/tauri-commands", () => ({
+  listMarketplaceUpdates: () => listMarketplaceUpdates(),
+}));
+
+describe("MarketplaceSettings", () => {
+  beforeEach(() => {
+    vi.clearAllMocks();
+    useAppState.setState({
+      tabOrder: [],
+      activeTabKey: null,
+      appSettings: {
+        marketplaces: [{ id: "m1", name: "Starter", url: "https://x/y.git", branch: null, account_id: null }],
+        global_marketplace_installs: [
+          { marketplace_id: "m1", kind: "agent", key: "a", commit: "a".repeat(40) },
+          { marketplace_id: "m1", kind: "hook", key: "h", commit: "a".repeat(40) },
+        ],
+        marketplace_accounts: [],
+      } as unknown as AppSettings,
+    });
+    listMarketplaceUpdates.mockResolvedValue([
+      { item: { marketplace_id: "m1", kind: "agent", key: "a" }, pinned: "a".repeat(40), head: "b".repeat(40) },
+    ]);
+  });
+
+  it("summarises and opens the Marketplace tab", async () => {
+    render(<MarketplaceSettings />);
+    expect(screen.getByTestId("marketplace-summary")).toHaveTextContent("1 marketplace");
+    expect(screen.getByTestId("marketplace-summary")).toHaveTextContent("2 installed for all projects");
+    await waitFor(() =>
+      expect(screen.getByTestId("marketplace-summary")).toHaveTextContent("1 update available"),
+    );
+    fireEvent.click(screen.getByRole("button", { name: "Open Marketplace" }));
+    expect(useAppState.getState().activeTabKey).toBe(MARKETPLACE_TAB_KEY);
+  });
+});
diff --git a/app/src/components/settings/MarketplaceSettings.tsx b/app/src/components/settings/MarketplaceSettings.tsx
new file mode 100644
index 0000000..7f1dc25
--- /dev/null
+++ b/app/src/components/settings/MarketplaceSettings.tsx
@@ -0,0 +1,48 @@
+import { useEffect, useState } from "react";
+import { useAppState } from "../../store/appState";
+import { listMarketplaceUpdates } from "../../lib/tauri-commands";
+import Button from "../ui/Button";
+
+const plural = (n: number, one: string, many: string) => `${n} ${n === 1 ? one : many}`;
+
+export default function MarketplaceSettings() {
+  const appSettings = useAppState((s) => s.appSettings);
+  const openMarketplace = useAppState((s) => s.openMarketplace);
+  const [updateCount, setUpdateCount] = useState<number | null>(null);
+
+  useEffect(() => {
+    let cancelled = false;
+    listMarketplaceUpdates()
+      .then((u) => {
+        if (!cancelled) setUpdateCount(u.length);
+      })
+      .catch(() => {
+        if (!cancelled) setUpdateCount(null);
+      });
+    return () => {
+      cancelled = true;
+    };
+  }, [appSettings?.marketplaces.length]);
+
+  const marketplaces = appSettings?.marketplaces.length ?? 0;
+  const globalInstalls = appSettings?.global_marketplace_installs.length ?? 0;
+
+  return (
+    <div className="space-y-2">
+      <p data-testid="marketplace-summary" className="text-xs text-[var(--text-secondary)] leading-snug">
+        {plural(marketplaces, "marketplace", "marketplaces")} ·{" "}
+        {globalInstalls} installed for all projects
+        {updateCount !== null && updateCount > 0 && (
+          <> · {plural(updateCount, "update available", "updates available")}</>
+        )}
+      </p>
+      <p className="text-xs text-[var(--text-secondary)] leading-snug">
+        Agents, skills, commands, hooks and plugins from git repositories, installed for all
+        projects or per project. Changes apply to new Claude sessions.
+      </p>
+      <Button size="md" variant="secondary" onClick={() => openMarketplace()}>
+        Open Marketplace
+      </Button>
+    </div>
+  );
+}
diff --git a/app/src/components/settings/SettingsPanel.tsx b/app/src/components/settings/SettingsPanel.tsx
index 6eba2cb..21e0ab4 100644
--- a/app/src/components/settings/SettingsPanel.tsx
+++ b/app/src/components/settings/SettingsPanel.tsx
@@ -20,6 +20,7 @@ import { resolveTerminalGpuRendering } from "../../lib/terminalRenderer";
 import WebTerminalSettings from "./WebTerminalSettings";
 import SttSettings from "./SttSettings";
 import SharedAuthSettings from "./SharedAuthSettings";
+import MarketplaceSettings from "./MarketplaceSettings";
 import CertificateSettings from "./CertificateSettings";
 import ExportSettingsModal from "./ExportSettingsModal";
 import ImportSettingsModal from "./ImportSettingsModal";
@@ -171,6 +172,10 @@ export default function SettingsPanel() {
         <SharedAuthSettings />
       </AccordionSection>
 
+      <AccordionSection id="marketplace" title="Marketplace" defaultOpen={false}>
+        <MarketplaceSettings />
+      </AccordionSection>
+
       <AccordionSection id="backends" title="Backends" defaultOpen={false}>
         <AwsSettings />
         <div className="pt-3 border-t border-[var(--border-color)]" />
diff --git a/app/src/hooks/useKeyboardShortcuts.test.tsx b/app/src/hooks/useKeyboardShortcuts.test.tsx
index 98bfa9e..77c7190 100644
--- a/app/src/hooks/useKeyboardShortcuts.test.tsx
+++ b/app/src/hooks/useKeyboardShortcuts.test.tsx
@@ -1,7 +1,7 @@
 import { describe, it, expect, vi, beforeEach, afterEach } from "vitest";
 import { renderHook } from "@testing-library/react";
 import { useKeyboardShortcuts } from "./useKeyboardShortcuts";
-import { useAppState, homeTabKey, terminalTabKey } from "../store/appState";
+import { useAppState, homeTabKey, terminalTabKey, MARKETPLACE_TAB_KEY } from "../store/appState";
 
 vi.mock("./useTerminal", () => ({
   useTerminal: () => ({ open: vi.fn(), close: vi.fn() }),
@@ -86,3 +86,16 @@ describe("Ctrl+Shift+←/→", () => {
     expect(order()).toEqual([HOME, S1, S2]);
   });
 });
+
+describe("Ctrl+Shift+W on the Marketplace tab", () => {
+  it("closes the Marketplace tab", () => {
+    useAppState.setState({
+      tabOrder: [HOME, MARKETPLACE_TAB_KEY],
+      activeTabKey: MARKETPLACE_TAB_KEY,
+      activeSessionId: null,
+    });
+    renderHook(() => useKeyboardShortcuts());
+    press("W", { shift: true });
+    expect(useAppState.getState().tabOrder).toEqual([HOME]);
+  });
+});
diff --git a/app/src/hooks/useKeyboardShortcuts.ts b/app/src/hooks/useKeyboardShortcuts.ts
index fbcc47a..285ffad 100644
--- a/app/src/hooks/useKeyboardShortcuts.ts
+++ b/app/src/hooks/useKeyboardShortcuts.ts
@@ -1,5 +1,5 @@
 import { useEffect } from "react";
-import { useAppState, isTerminalTab, tabKeyId } from "../store/appState";
+import { useAppState, isMarketplaceTab, isTerminalTab, tabKeyId } from "../store/appState";
 import { useTerminal } from "./useTerminal";
 
 /**
@@ -62,6 +62,8 @@ export function useKeyboardShortcuts() {
           closeTerminal(tabKeyId(key)).catch((err) =>
             console.error("Failed to close terminal:", err),
           );
+        } else if (isMarketplaceTab(key)) {
+          state.closeMarketplaceTab();
         } else {
           state.closeHomeTab(tabKeyId(key));
         }
diff --git a/app/src/hooks/useMarketplace.test.ts b/app/src/hooks/useMarketplace.test.ts
new file mode 100644
index 0000000..7aa27b3
--- /dev/null
+++ b/app/src/hooks/useMarketplace.test.ts
@@ -0,0 +1,120 @@
+import { describe, it, expect, vi, beforeEach } from "vitest";
+import { act, renderHook, waitFor } from "@testing-library/react";
+import { useAppState } from "../store/appState";
+import type { AppSettings, MarketplaceSnapshot } from "../lib/types";
+
+const listMarketplaceSnapshots = vi.fn();
+const refreshMarketplaces = vi.fn();
+const listMarketplaceUpdates = vi.fn();
+const getSettings = vi.fn();
+const listProjects = vi.fn();
+const installMarketplaceItem = vi.fn();
+
+vi.mock("../lib/tauri-commands", () => ({
+  listMarketplaceSnapshots: () => listMarketplaceSnapshots(),
+  refreshMarketplaces: (id?: string) => refreshMarketplaces(id),
+  listMarketplaceUpdates: () => listMarketplaceUpdates(),
+  getSettings: () => getSettings(),
+  listProjects: () => listProjects(),
+  installMarketplaceItem: (...a: unknown[]) => installMarketplaceItem(...a),
+}));
+
+let syncHandler: ((e: { payload: unknown }) => void) | null = null;
+vi.mock("@tauri-apps/api/event", () => ({
+  listen: vi.fn(async (_name: string, cb: (e: { payload: unknown }) => void) => {
+    syncHandler = cb;
+    return vi.fn();
+  }),
+}));
+
+import { useMarketplace, useMarketplaceSyncToasts } from "./useMarketplace";
+
+const snap = (id: string, fetched_at: string | null): MarketplaceSnapshot => ({
+  marketplace_id: id,
+  head_commit: null,
+  fetched_at,
+  fetch_error: null,
+  items: [],
+});
+
+describe("useMarketplace", () => {
+  beforeEach(() => {
+    vi.clearAllMocks();
+    useAppState.setState({ toasts: [], appSettings: { marketplaces: [] } as unknown as AppSettings });
+    listMarketplaceUpdates.mockResolvedValue([]);
+    getSettings.mockResolvedValue({ marketplaces: [] });
+    listProjects.mockResolvedValue([]);
+  });
+
+  it("loads snapshots and refreshes only stale ones", async () => {
+    const fresh = snap("m1", new Date().toISOString());
+    const stale = snap("m2", null);
+    listMarketplaceSnapshots.mockResolvedValue([fresh, stale]);
+    refreshMarketplaces.mockResolvedValue([{ ...stale, fetched_at: new Date().toISOString() }]);
+
+    const { result } = renderHook(() => useMarketplace());
+    await act(() => result.current.load({ refreshStale: true }));
+
+    expect(refreshMarketplaces).toHaveBeenCalledTimes(1);
+    expect(refreshMarketplaces).toHaveBeenCalledWith("m2");
+    expect(result.current.snapshots.map((s) => s.marketplace_id)).toEqual(["m1", "m2"]);
+    expect(result.current.snapshots[1].fetched_at).not.toBeNull();
+  });
+
+  it("toasts and reloads after a failed mutation", async () => {
+    listMarketplaceSnapshots.mockResolvedValue([]);
+    installMarketplaceItem.mockRejectedValue("boom");
+    const { result } = renderHook(() => useMarketplace());
+    const ok = await act(() =>
+      result.current.install({ marketplace_id: "m1", kind: "agent", key: "a" }, { type: "global" }),
+    );
+    expect(ok).toBe(false);
+    expect(useAppState.getState().toasts[0]).toMatchObject({ kind: "error", detail: "boom" });
+  });
+});
+
+describe("useMarketplaceSyncToasts", () => {
+  beforeEach(() => {
+    syncHandler = null;
+    useAppState.setState({
+      toasts: [],
+      projects: [{ id: "p1", name: "api" }] as never,
+    });
+  });
+
+  it("toasts a sync with errors and stays quiet on a clean one", async () => {
+    renderHook(() => useMarketplaceSyncToasts());
+    await waitFor(() => expect(syncHandler).not.toBeNull());
+
+    act(() =>
+      syncHandler!({
+        payload: {
+          project_id: "p1",
+          report: { installed: ["agent:a"], updated: [], removed: [], skipped: [], errors: [], finished_at: "" },
+        },
+      }),
+    );
+    expect(useAppState.getState().toasts).toHaveLength(0);
+
+    act(() =>
+      syncHandler!({
+        payload: {
+          project_id: "p1",
+          report: {
+            installed: [],
+            updated: [],
+            removed: [],
+            skipped: [{ item: "agent:a", reason: "a file you created has the same name" }],
+            errors: ["claude plugin install failed"],
+            finished_at: "",
+          },
+        },
+      }),
+    );
+    const toast = useAppState.getState().toasts[0];
+    expect(toast.kind).toBe("error");
+    expect(toast.message).toContain("api");
+    expect(toast.detail).toContain("claude plugin install failed");
+    expect(toast.detail).toContain("agent:a");
+  });
+});
diff --git a/app/src/hooks/useMarketplace.ts b/app/src/hooks/useMarketplace.ts
new file mode 100644
index 0000000..e1f57ae
--- /dev/null
+++ b/app/src/hooks/useMarketplace.ts
@@ -0,0 +1,208 @@
+import { useCallback, useEffect, useState } from "react";
+import { listen, type UnlistenFn } from "@tauri-apps/api/event";
+import * as commands from "../lib/tauri-commands";
+import { useAppState } from "../store/appState";
+import { isStale } from "../lib/marketplace";
+import type {
+  InstallScope,
+  ItemUpdate,
+  MarketplaceItemRef,
+  MarketplaceSnapshot,
+  SyncReport,
+} from "../lib/types";
+
+export interface MarketplaceApi {
+  snapshots: MarketplaceSnapshot[];
+  updates: ItemUpdate[];
+  loading: boolean;
+  /** Ids of marketplaces currently being fetched. */
+  refreshing: string[];
+  load: (opts?: { refreshStale?: boolean }) => Promise<void>;
+  refresh: (marketplaceId?: string) => Promise<void>;
+  /** Reload settings, projects and the update list after a mutation. */
+  reloadState: () => Promise<void>;
+  install: (item: MarketplaceItemRef, scope: InstallScope) => Promise<boolean>;
+  uninstall: (item: MarketplaceItemRef, scope: InstallScope) => Promise<boolean>;
+  setDisabled: (projectId: string, item: MarketplaceItemRef, disabled: boolean) => Promise<boolean>;
+  update: (item: MarketplaceItemRef, scope: InstallScope) => Promise<boolean>;
+  forget: (marketplaceId: string) => Promise<boolean>;
+  remove: (marketplaceId: string) => Promise<boolean>;
+}
+
+function errorText(e: unknown): string {
+  return typeof e === "string" ? e : e instanceof Error ? e.message : String(e);
+}
+
+export function useMarketplace(): MarketplaceApi {
+  const setAppSettings = useAppState((s) => s.setAppSettings);
+  const setProjects = useAppState((s) => s.setProjects);
+  const pushToast = useAppState((s) => s.pushToast);
+  const [snapshots, setSnapshots] = useState<MarketplaceSnapshot[]>([]);
+  const [updates, setUpdates] = useState<ItemUpdate[]>([]);
+  const [loading, setLoading] = useState(false);
+  const [refreshing, setRefreshing] = useState<string[]>([]);
+
+  const merge = useCallback((fresh: MarketplaceSnapshot[]) => {
+    setSnapshots((prev) => {
+      const byId = new Map(prev.map((s) => [s.marketplace_id, s]));
+      for (const s of fresh) byId.set(s.marketplace_id, s);
+      return [...byId.values()];
+    });
+  }, []);
+
+  const loadUpdates = useCallback(async () => {
+    try {
+      setUpdates(await commands.listMarketplaceUpdates());
+    } catch (e) {
+      console.error("Failed to list marketplace updates:", e);
+    }
+  }, []);
+
+  const refresh = useCallback(
+    async (marketplaceId?: string) => {
+      const ids = marketplaceId ? [marketplaceId] : snapshots.map((s) => s.marketplace_id);
+      setRefreshing((r) => [...new Set([...r, ...ids])]);
+      try {
+        merge(await commands.refreshMarketplaces(marketplaceId));
+        await loadUpdates();
+      } catch (e) {
+        pushToast({ kind: "error", message: "Could not refresh the marketplace", detail: errorText(e) });
+      } finally {
+        setRefreshing((r) => r.filter((id) => !ids.includes(id)));
+      }
+    },
+    [snapshots, merge, loadUpdates, pushToast],
+  );
+
+  const load = useCallback(
+    async (opts: { refreshStale?: boolean } = {}) => {
+      setLoading(true);
+      try {
+        const list = await commands.listMarketplaceSnapshots();
+        setSnapshots(list);
+        await loadUpdates();
+        if (opts.refreshStale) {
+          const now = Date.now();
+          const stale = list.filter((s) => isStale(s, now)).map((s) => s.marketplace_id);
+          if (stale.length > 0) {
+            setRefreshing(stale);
+            try {
+              // One call per marketplace so one slow or failing repo does not hold up the rest.
+              await Promise.all(
+                stale.map(async (id) => {
+                  try {
+                    merge(await commands.refreshMarketplaces(id));
+                  } finally {
+                    setRefreshing((r) => r.filter((x) => x !== id));
+                  }
+                }),
+              );
+            } finally {
+              await loadUpdates();
+            }
+          }
+        }
+      } catch (e) {
+        pushToast({ kind: "error", message: "Could not load marketplaces", detail: errorText(e) });
+      } finally {
+        setLoading(false);
+      }
+    },
+    [merge, loadUpdates, pushToast],
+  );
+
+  const reloadState = useCallback(async () => {
+    const [settings, projects] = await Promise.all([commands.getSettings(), commands.listProjects()]);
+    setAppSettings(settings);
+    setProjects(projects);
+    await loadUpdates();
+  }, [setAppSettings, setProjects, loadUpdates]);
+
+  /** Run a mutation; on failure toast it. Always resync local state afterwards. */
+  const mutate = useCallback(
+    async (label: string, run: () => Promise<unknown>): Promise<boolean> => {
+      let ok = true;
+      try {
+        await run();
+      } catch (e) {
+        ok = false;
+        pushToast({ kind: "error", message: label, detail: errorText(e) });
+      }
+      try {
+        await reloadState();
+      } catch (e) {
+        console.error("Failed to reload after marketplace change:", e);
+      }
+      return ok;
+    },
+    [reloadState, pushToast],
+  );
+
+  return {
+    snapshots,
+    updates,
+    loading,
+    refreshing,
+    load,
+    refresh,
+    reloadState,
+    install: (item, scope) =>
+      mutate(`Could not install ${item.key}`, () => commands.installMarketplaceItem(item, scope)),
+    uninstall: (item, scope) =>
+      mutate(`Could not remove ${item.key}`, () => commands.uninstallMarketplaceItem(item, scope)),
+    setDisabled: (projectId, item, disabled) =>
+      mutate(`Could not change ${item.key} for this project`, () =>
+        commands.setGlobalItemDisabled(projectId, item, disabled),
+      ),
+    update: (item, scope) =>
+      mutate(`Could not update ${item.key}`, () => commands.updateMarketplaceItem(item, scope)),
+    forget: (marketplaceId) =>
+      mutate("Could not forget those installs", () => commands.forgetMarketplaceInstalls(marketplaceId)),
+    remove: async (marketplaceId) => {
+      const ok = await mutate("Could not remove the marketplace", () =>
+        commands.removeMarketplace(marketplaceId),
+      );
+      if (ok) setSnapshots((prev) => prev.filter((s) => s.marketplace_id !== marketplaceId));
+      return ok;
+    },
+  };
+}
+
+interface SyncFinishedEvent {
+  project_id: string;
+  report: SyncReport;
+}
+
+/**
+ * App-wide: toast when a marketplace sync (container start or "Apply now")
+ * reports errors or skipped items. A clean sync is silent.
+ */
+export function useMarketplaceSyncToasts() {
+  useEffect(() => {
+    let cancelled = false;
+    let unlisten: UnlistenFn | null = null;
+    void listen<SyncFinishedEvent>("marketplace-sync-finished", (event) => {
+      const { project_id, report } = event.payload;
+      if (report.errors.length === 0 && report.skipped.length === 0) return;
+      const state = useAppState.getState();
+      const name = state.projects.find((p) => p.id === project_id)?.name ?? project_id;
+      const lines = [
+        ...report.errors,
+        ...report.skipped.map((s) => `${s.item}: ${s.reason}`),
+      ];
+      state.pushToast({
+        kind: report.errors.length > 0 ? "error" : "info",
+        message: `Marketplace sync for “${name}” ${report.errors.length > 0 ? "had errors" : "skipped items"}`,
+        detail: lines.join("\n"),
+        dedupeKey: `marketplace-sync-${project_id}`,
+      });
+    }).then((fn) => {
+      if (cancelled) fn();
+      else unlisten = fn;
+    });
+    return () => {
+      cancelled = true;
+      unlisten?.();
+    };
+  }, []);
+}
diff --git a/app/src/lib/marketplace.test.ts b/app/src/lib/marketplace.test.ts
new file mode 100644
index 0000000..f9986e9
--- /dev/null
+++ b/app/src/lib/marketplace.test.ts
@@ -0,0 +1,113 @@
+import { describe, it, expect } from "vitest";
+import {
+  effectiveInstalls,
+  formatItemRef,
+  isStale,
+  itemRefKey,
+  projectItemState,
+  STALE_AFTER_MS,
+} from "./marketplace";
+import type { MarketplaceInstall, MarketplaceSnapshot, Project } from "./types";
+
+const A = "a".repeat(40);
+const B = "b".repeat(40);
+
+const inst = (key: string, commit = A, kind: MarketplaceInstall["kind"] = "agent"): MarketplaceInstall => ({
+  marketplace_id: "m1",
+  kind,
+  key,
+  commit,
+});
+
+const project = (patch: Partial<Project> = {}): Project =>
+  ({
+    id: "p1",
+    name: "api",
+    marketplace_installs: [],
+    marketplace_disabled: [],
+    ...patch,
+  }) as unknown as Project;
+
+describe("itemRefKey / formatItemRef", () => {
+  it("keys and formats a ref", () => {
+    const r = { marketplace_id: "m1", kind: "hook" as const, key: "notify" };
+    expect(itemRefKey(r)).toBe("m1/hook/notify");
+    expect(formatItemRef(r)).toBe("hook:notify");
+  });
+});
+
+describe("projectItemState", () => {
+  const ref = { marketplace_id: "m1", kind: "agent" as const, key: "rev" };
+
+  it("is none when nothing installs it", () => {
+    expect(projectItemState(ref, [], project())).toBe("none");
+  });
+
+  it("is inherited from a global install", () => {
+    expect(projectItemState(ref, [inst("rev")], project())).toBe("inherited");
+  });
+
+  it("is opted_out when the project disabled the global install", () => {
+    const p = project({ marketplace_disabled: [ref] });
+    expect(projectItemState(ref, [inst("rev")], p)).toBe("opted_out");
+  });
+
+  it("is project for a project-only install", () => {
+    const p = project({ marketplace_installs: [inst("rev")] });
+    expect(projectItemState(ref, [], p)).toBe("project");
+  });
+
+  it("is project when project and global share the pin", () => {
+    const p = project({ marketplace_installs: [inst("rev", A)] });
+    expect(projectItemState(ref, [inst("rev", A)], p)).toBe("project");
+  });
+
+  it("flags a project pin that differs from the global pin", () => {
+    const p = project({ marketplace_installs: [inst("rev", B)] });
+    expect(projectItemState(ref, [inst("rev", A)], p)).toBe("project_pinned_differently");
+  });
+
+  it("does not confuse kinds with the same key", () => {
+    expect(projectItemState(ref, [inst("rev", A, "skill")], project())).toBe("none");
+  });
+});
+
+describe("effectiveInstalls", () => {
+  it("merges global minus disabled plus project, project winning", () => {
+    const disabledRef = { marketplace_id: "m1", kind: "agent" as const, key: "off" };
+    const p = project({
+      marketplace_disabled: [disabledRef],
+      marketplace_installs: [inst("both", B), inst("mine")],
+    });
+    const out = effectiveInstalls([inst("glob"), inst("off"), inst("both", A)], p);
+    expect(out.map((i) => [i.key, i.commit, i.source])).toEqual([
+      ["both", B, "project"],
+      ["glob", A, "global"],
+      ["mine", A, "project"],
+    ]);
+  });
+});
+
+describe("isStale", () => {
+  const snap = (fetched_at: string | null): MarketplaceSnapshot => ({
+    marketplace_id: "m1",
+    head_commit: null,
+    fetched_at,
+    fetch_error: null,
+    items: [],
+  });
+  const now = Date.parse("2026-09-27T12:00:00Z");
+
+  it("treats a never-fetched snapshot as stale", () => {
+    expect(isStale(snap(null), now)).toBe(true);
+  });
+
+  it("is fresh within 15 minutes and stale after", () => {
+    expect(isStale(snap(new Date(now - STALE_AFTER_MS + 1000).toISOString()), now)).toBe(false);
+    expect(isStale(snap(new Date(now - STALE_AFTER_MS - 1000).toISOString()), now)).toBe(true);
+  });
+
+  it("treats an unparsable timestamp as stale", () => {
+    expect(isStale(snap("not a date"), now)).toBe(true);
+  });
+});
diff --git a/app/src/lib/marketplace.ts b/app/src/lib/marketplace.ts
new file mode 100644
index 0000000..587232e
--- /dev/null
+++ b/app/src/lib/marketplace.ts
@@ -0,0 +1,75 @@
+import type {
+  ItemKind,
+  MarketplaceInstall,
+  MarketplaceItemRef,
+  MarketplaceSnapshot,
+  Project,
+} from "./types";
+
+/** How a project relates to one marketplace item. */
+export type ProjectItemState =
+  | "none"
+  | "inherited"
+  | "opted_out"
+  | "project"
+  | "project_pinned_differently";
+
+export const KIND_ORDER: ItemKind[] = ["agent", "skill", "command", "hook", "plugin"];
+
+export const KIND_LABELS: Record<ItemKind, string> = {
+  agent: "Agents",
+  skill: "Skills",
+  command: "Commands",
+  hook: "Hooks",
+  plugin: "Plugins",
+};
+
+/** A marketplace is refreshed when its tab opens if the last fetch is older than this. */
+export const STALE_AFTER_MS = 15 * 60 * 1000;
+
+export const itemRefKey = (r: MarketplaceItemRef) => `${r.marketplace_id}/${r.kind}/${r.key}`;
+
+/** Same shape as the item strings in a `SyncReport`. */
+export const formatItemRef = (r: MarketplaceItemRef) => `${r.kind}:${r.key}`;
+
+const sameItem = (a: MarketplaceItemRef, b: MarketplaceItemRef) =>
+  a.marketplace_id === b.marketplace_id && a.kind === b.kind && a.key === b.key;
+
+export function projectItemState(
+  item: MarketplaceItemRef,
+  globalInstalls: MarketplaceInstall[],
+  project: Project,
+): ProjectItemState {
+  const own = project.marketplace_installs.find((i) => sameItem(i, item));
+  const global = globalInstalls.find((i) => sameItem(i, item));
+  if (own) {
+    return global && global.commit !== own.commit ? "project_pinned_differently" : "project";
+  }
+  if (!global) return "none";
+  return project.marketplace_disabled.some((d) => sameItem(d, item)) ? "opted_out" : "inherited";
+}
+
+/** Mirror of the backend's `effective_installs`, tagged with where each install comes from. */
+export function effectiveInstalls(
+  globalInstalls: MarketplaceInstall[],
+  project: Project,
+): (MarketplaceInstall & { source: "global" | "project" })[] {
+  const byKey = new Map<string, MarketplaceInstall & { source: "global" | "project" }>();
+  for (const g of globalInstalls) {
+    if (project.marketplace_disabled.some((d) => sameItem(d, g))) continue;
+    byKey.set(itemRefKey(g), { ...g, source: "global" });
+  }
+  for (const p of project.marketplace_installs) {
+    byKey.set(itemRefKey(p), { ...p, source: "project" });
+  }
+  return [...byKey.entries()]
+    .sort(([a], [b]) => (a < b ? -1 : a > b ? 1 : 0))
+    .map(([, v]) => v);
+}
+
+export function isStale(snapshot: MarketplaceSnapshot, now: number): boolean {
+  if (!snapshot.fetched_at) return true;
+  const at = Date.parse(snapshot.fetched_at);
+  if (Number.isNaN(at)) return true;
+  return now - at > STALE_AFTER_MS;
+}
diff --git a/app/src/lib/tauri-commands.ts b/app/src/lib/tauri-commands.ts
index d286b7e..c911dcb 100644
--- a/app/src/lib/tauri-commands.ts
+++ b/app/src/lib/tauri-commands.ts
@@ -1,5 +1,5 @@
 import { invoke } from "@tauri-apps/api/core";
-import type { Project, ProjectPath, ProjectRemovalReport, ProjectResetOutcome, ContainerInfo, AppSettings, SettingsImportPreview, SettingsImportOutcome, UpdateInfo, ImageUpdateInfo, FileEntry, FileContents, WebTerminalInfo, SttStatus, GatewayStatus, InstallOptions, ClaudeSession, ContainerCapabilities, ScheduledTask, ScheduledTaskInput, SchedulerNotification, AuthBridgeStatus, BrowserViewStatus, BrowserViewPopoutState, BrowserPageState, PlaywrightDetection, BrowserSetupOutcome, BrowserInstallTarget, ContainerStaleness, MigrationOptions, MigrationReport, MigrationState, ClearTokenOutcome, CaCertInfo, UploadOutcome, Note, ViewerFile, ViewerPoll, ViewerSaved, ViewerState } from "./types";
+import type { Project, ProjectPath, ProjectRemovalReport, ProjectResetOutcome, ContainerInfo, AppSettings, SettingsImportPreview, SettingsImportOutcome, UpdateInfo, ImageUpdateInfo, FileEntry, FileContents, WebTerminalInfo, SttStatus, GatewayStatus, InstallOptions, ClaudeSession, ContainerCapabilities, ScheduledTask, ScheduledTaskInput, SchedulerNotification, AuthBridgeStatus, BrowserViewStatus, BrowserViewPopoutState, BrowserPageState, PlaywrightDetection, BrowserSetupOutcome, BrowserInstallTarget, ContainerStaleness, MigrationOptions, MigrationReport, MigrationState, ClearTokenOutcome, CaCertInfo, UploadOutcome, Note, ViewerFile, ViewerPoll, ViewerSaved, ViewerState, FileDiff, InstallScope, ItemUpdate, Marketplace, MarketplaceAccount, MarketplaceItemRef, MarketplaceSnapshot, ProjectSyncResult, SyncReport } from "./types";
 
 // Docker
 export const checkDocker = () => invoke<boolean>("check_docker");
@@ -432,3 +432,55 @@ export const viewerWriteFile = (contentsBase64: string, baseHash: string) =>
   invoke<ViewerSaved>("viewer_write_file", { contentsBase64, baseHash });
 export const viewerChooseFile = (index: number) =>
   invoke<ViewerState>("viewer_choose_file", { index });
+
+// ---- Marketplace ----
+
+export const listMarketplaceSnapshots = () =>
+  invoke<MarketplaceSnapshot[]>("list_marketplace_snapshots");
+export const refreshMarketplaces = (marketplaceId?: string) =>
+  invoke<MarketplaceSnapshot[]>("refresh_marketplaces", { marketplaceId: marketplaceId ?? null });
+export const addMarketplace = (
+  name: string,
+  url: string,
+  branch: string | null,
+  accountId: string | null,
+) => invoke<MarketplaceSnapshot>("add_marketplace", { name, url, branch, accountId });
+export const updateMarketplace = (marketplace: Marketplace) =>
+  invoke<AppSettings>("update_marketplace", { marketplace });
+export const removeMarketplace = (marketplaceId: string) =>
+  invoke<AppSettings>("remove_marketplace", { marketplaceId });
+export const installMarketplaceItem = (item: MarketplaceItemRef, scope: InstallScope) =>
+  invoke<AppSettings>("install_marketplace_item", { item, scope });
+export const uninstallMarketplaceItem = (item: MarketplaceItemRef, scope: InstallScope) =>
+  invoke<void>("uninstall_marketplace_item", { item, scope });
+export const setGlobalItemDisabled = (
+  projectId: string,
+  item: MarketplaceItemRef,
+  disabled: boolean,
+) => invoke<Project>("set_global_item_disabled", { projectId, item, disabled });
+export const forgetMarketplaceInstalls = (marketplaceId: string) =>
+  invoke<void>("forget_marketplace_installs", { marketplaceId });
+export const listMarketplaceUpdates = () => invoke<ItemUpdate[]>("list_marketplace_updates");
+export const marketplaceItemDiff = (
+  item: MarketplaceItemRef,
+  fromCommit: string,
+  toCommit: string,
+) => invoke<FileDiff[]>("marketplace_item_diff", { item, fromCommit, toCommit });
+export const updateMarketplaceItem = (item: MarketplaceItemRef, scope: InstallScope) =>
+  invoke<void>("update_marketplace_item", { item, scope });
+export const applyMarketplaceNow = (projectId?: string) =>
+  invoke<ProjectSyncResult[]>("apply_marketplace_now", { projectId: projectId ?? null });
+export const getMarketplaceSyncReport = (projectId: string) =>
+  invoke<SyncReport | null>("get_marketplace_sync_report", { projectId });
+export const addMarketplaceTokenAccount = (label: string, host: string, token: string) =>
+  invoke<MarketplaceAccount>("add_marketplace_token_account", { label, host, token });
+export const addMarketplaceGhHostAccount = (label: string, host: string) =>
+  invoke<MarketplaceAccount>("add_marketplace_gh_host_account", { label, host });
+export const startMarketplaceGhContainerLogin = (label: string, host: string, projectId: string) =>
+  invoke<MarketplaceAccount>("start_marketplace_gh_container_login", { label, host, projectId });
+export const cancelMarketplaceGhLogin = () => invoke<void>("cancel_marketplace_gh_login");
+export const testMarketplaceAccount = (accountId: string) =>
+  invoke<string>("test_marketplace_account", { accountId });
+export const removeMarketplaceAccount = (accountId: string) =>
+  invoke<AppSettings>("remove_marketplace_account", { accountId });
+export const marketplaceGhHostAvailable = () => invoke<boolean>("marketplace_gh_host_available");
diff --git a/app/src/store/appState.test.ts b/app/src/store/appState.test.ts
index 606680b..95f389f 100644
--- a/app/src/store/appState.test.ts
+++ b/app/src/store/appState.test.ts
@@ -1,5 +1,5 @@
 import { describe, it, expect, beforeEach } from "vitest";
-import { useAppState, homeTabKey, terminalTabKey } from "./appState";
+import { useAppState, homeTabKey, terminalTabKey, MARKETPLACE_TAB_KEY } from "./appState";
 
 const A = homeTabKey("a");
 const B = terminalTabKey("b");
@@ -136,3 +136,45 @@ describe("terminal focus requests", () => {
     expect(pending()).toBe("s1");
   });
 });
+
+describe("marketplace tab", () => {
+  beforeEach(() => {
+    seed([A, B], A);
+    useAppState.setState({ marketplaceFilterProjectId: null });
+  });
+
+  it("opens once, activates, and records the project filter", () => {
+    useAppState.getState().openMarketplace("p9");
+    useAppState.getState().openMarketplace("p9");
+    const s = useAppState.getState();
+    expect(s.tabOrder).toEqual([A, B, MARKETPLACE_TAB_KEY]);
+    expect(s.activeTabKey).toBe(MARKETPLACE_TAB_KEY);
+    expect(s.activeSessionId).toBeNull();
+    expect(s.marketplaceFilterProjectId).toBe("p9");
+  });
+
+  it("clears the filter when opened without a project", () => {
+    useAppState.getState().openMarketplace("p9");
+    useAppState.getState().openMarketplace();
+    expect(useAppState.getState().marketplaceFilterProjectId).toBeNull();
+  });
+
+  it("does not select a project when activated", () => {
+    useAppState.getState().openMarketplace();
+    useAppState.getState().setActiveTabKey(MARKETPLACE_TAB_KEY);
+    expect(useAppState.getState().selectedProjectId).toBeNull();
+  });
+
+  it("closes and activates the neighbour", () => {
+    useAppState.getState().openMarketplace();
+    useAppState.getState().closeMarketplaceTab();
+    const s = useAppState.getState();
+    expect(s.tabOrder).toEqual([A, B]);
+    expect(s.activeTabKey).toBe(B);
+  });
+
+  it("closing when not open is a no-op", () => {
+    useAppState.getState().closeMarketplaceTab();
+    expect(useAppState.getState().tabOrder).toEqual([A, B]);
+  });
+});
diff --git a/app/src/store/appState.ts b/app/src/store/appState.ts
index 3216c45..bf2dec3 100644
--- a/app/src/store/appState.ts
+++ b/app/src/store/appState.ts
@@ -85,6 +85,10 @@ export const isTerminalTab = (key: string) => key.startsWith("term:");
 export const isHomeTab = (key: string) => key.startsWith("home:");
 export const tabKeyId = (key: string) => key.slice(key.indexOf(":") + 1);
 
+/** The Marketplace view is a singleton main-area tab; its key has no id part. */
+export const MARKETPLACE_TAB_KEY = "marketplace";
+export const isMarketplaceTab = (key: string) => key === MARKETPLACE_TAB_KEY;
+
 /** activeSessionId is derived from the active tab so exactly one thing is "current". */
 function activation(activeTabKey: string | null) {
   return {
@@ -160,6 +164,12 @@ interface AppState {
   requestTerminalFocus: (sessionId: string) => void;
   clearPendingTerminalFocus: () => void;
   closeHomeTab: (projectId: string) => void;
+  /** Project the Marketplace view is filtered to, or null for all projects. */
+  marketplaceFilterProjectId: string | null;
+  setMarketplaceFilterProjectId: (projectId: string | null) => void;
+  /** Open (or focus) the singleton Marketplace tab, optionally filtered to one project. */
+  openMarketplace: (filterProjectId?: string | null) => void;
+  closeMarketplaceTab: () => void;
   setActiveTabKey: (key: string) => void;
   cycleTab: (delta: number) => void;
   focusTabIndex: (index: number) => void;
@@ -386,6 +396,27 @@ export const useAppState = create<AppState>((set) => ({
           : state.activeTabKey;
       return { tabOrder, ...activation(activeTabKey) };
     }),
+  marketplaceFilterProjectId: null,
+  setMarketplaceFilterProjectId: (projectId) => set({ marketplaceFilterProjectId: projectId }),
+  openMarketplace: (filterProjectId = null) =>
+    set((state) => ({
+      marketplaceFilterProjectId: filterProjectId,
+      tabOrder: state.tabOrder.includes(MARKETPLACE_TAB_KEY)
+        ? state.tabOrder
+        : [...state.tabOrder, MARKETPLACE_TAB_KEY],
+      ...activation(MARKETPLACE_TAB_KEY),
+    })),
+  closeMarketplaceTab: () =>
+    set((state) => {
+      const index = state.tabOrder.indexOf(MARKETPLACE_TAB_KEY);
+      if (index === -1) return {};
+      const tabOrder = state.tabOrder.filter((k) => k !== MARKETPLACE_TAB_KEY);
+      const activeTabKey =
+        state.activeTabKey === MARKETPLACE_TAB_KEY
+          ? (tabOrder[Math.min(index, tabOrder.length - 1)] ?? null)
+          : state.activeTabKey;
+      return { tabOrder, ...activation(activeTabKey) };
+    }),
   setActiveTabKey: (key) =>
     set((state) => {
       if (!state.tabOrder.includes(key)) return {};