diff --git a/frontend/src/features/layout/LayoutGrid.cellControlsLayering.test.tsx b/frontend/src/features/layout/LayoutGrid.cellControlsLayering.test.tsx
index fbbdeec..887a09c 100644
--- a/frontend/src/features/layout/LayoutGrid.cellControlsLayering.test.tsx
+++ b/frontend/src/features/layout/LayoutGrid.cellControlsLayering.test.tsx
@@ -48,8 +48,10 @@ if (typeof globalThis.ResizeObserver === "undefined") {
 import type { DomainEvent } from "@/domain";
 import type { Gateways } from "@/ports";
 import {
+  MOCK_REFERENCE_PROFILES,
   MockAgentGateway,
   MockLayoutGateway,
+  MockProfileGateway,
   MockSystemGateway,
   MockTerminalGateway,
 } from "@/adapters/mock";
@@ -69,12 +71,14 @@ interface GridSetup {
 async function makeSplitAgentGrid(): Promise<GridSetup> {
   const layout = new MockLayoutGateway();
   const agentGateway = new MockAgentGateway();
+  const profileGateway = new MockProfileGateway();
   const terminal = new MockTerminalGateway();
   const system = new MockSystemGateway();
+  await profileGateway.saveProfile(MOCK_REFERENCE_PROFILES[0]);
 
   const agent = await agentGateway.createAgent("p1", {
     name: "Worker",
-    profileId: "claude",
+    profileId: "mock-claude",
   });
 
   const initial = await layout.loadLayout("p1");
@@ -98,6 +102,7 @@ async function makeSplitAgentGrid(): Promise<GridSetup> {
     gateways: {
       layout,
       agent: agentGateway,
+      profile: profileGateway,
       terminal,
       system,
     } as unknown as Gateways,
@@ -174,6 +179,24 @@ function expectedOperation(action: CellAction, cellId: string) {
 }
 
 describe("LayoutGrid — ticket #48 cell control layering", () => {
+  it("keeps custom CLI mode controls compact inside the cell toolbar (#151)", async () => {
+    const setup = await makeSplitAgentGrid();
+
+    renderGrid(setup.gateways);
+
+    const group = await screen.findByRole("group", {
+      name: `mode CLI agent ${setup.bId}`,
+    });
+    const { controls } = controlsFor(setup.bId);
+
+    expect(group.textContent).toBe("TUI nativeCLI custom");
+    expect(group.style.maxWidth).toBe("128px");
+    expect(controls.style.left).toBe("4px");
+    expect(controls.style.right).toBe("16px");
+    expect(controls.style.justifyContent).toBe("flex-end");
+    expect(controls.style.overflow).toBe("hidden");
+  });
+
   it.each<CellAction>(["selector", "split", "close"])(
     "keeps %s above/clickable over a terminal launch error",
     async (action) => {
diff --git a/frontend/src/features/layout/LayoutGrid.tsx b/frontend/src/features/layout/LayoutGrid.tsx
index a00a4cb..0a0f02b 100644
--- a/frontend/src/features/layout/LayoutGrid.tsx
+++ b/frontend/src/features/layout/LayoutGrid.tsx
@@ -922,6 +922,13 @@ function LeafView({
         if (!conversationId) {
           return doLaunch(opts, onData, undefined);
         }
+        // If the cell was closed/remounted while the agent was running, resume
+        // silently. Layout/project changes must not interrupt an ongoing turn
+        // with a modal choice; the persisted conversation id is the continuity
+        // signal and `agentWasRunning` tells us this was not an intentional stop.
+        if (agentWasRunning) {
+          return doLaunch(opts, onData, conversationId);
+        }
         // Resume case: defer the launch behind the popup. Fetch the best-effort
         // enriched details (last topic + tokens) to enrich it; failure or empty
         // ⇒ degraded mode (status only). Inspection never blocks the resume.
@@ -982,6 +989,7 @@ function LeafView({
         style={{
           position: "absolute",
           top: 2,
+          left: 4,
           // Clear the xterm viewport scrollbar (rendered flush against the right
           // edge, ~15px wide). Without this offset the right-most control — the
           // close button — sits *behind* the scrollbar and is hard to click.
@@ -992,6 +1000,8 @@ function LeafView({
           display: "flex",
           gap: 2,
           alignItems: "center",
+          justifyContent: "flex-end",
+          overflow: "hidden",
         }}
       >
         {/* Agent selector */}
@@ -1053,7 +1063,8 @@ function LeafView({
             border: "1px solid var(--color-border, #3a3a3a)",
             borderRadius: 3,
             padding: "1px 2px",
-            maxWidth: 100,
+            width: 96,
+            minWidth: 56,
           }}
         >
           <option value="">Plain</option>
@@ -1079,6 +1090,7 @@ function LeafView({
               border: "1px solid var(--color-border, #3a3a3a)",
               borderRadius: 3,
               background: "var(--color-surface, #1e1e1e)",
+              maxWidth: 128,
             }}
           >
             <button
@@ -1100,6 +1112,10 @@ function LeafView({
                 fontSize: 11,
                 padding: "1px 6px",
                 cursor: "pointer",
+                maxWidth: 66,
+                overflow: "hidden",
+                textOverflow: "ellipsis",
+                whiteSpace: "nowrap",
               }}
             >
               TUI native
@@ -1122,6 +1138,10 @@ function LeafView({
                 fontSize: 11,
                 padding: "1px 6px",
                 cursor: "pointer",
+                maxWidth: 70,
+                overflow: "hidden",
+                textOverflow: "ellipsis",
+                whiteSpace: "nowrap",
               }}
             >
               CLI custom
diff --git a/frontend/src/features/layout/resumeConversationPopup.test.tsx b/frontend/src/features/layout/resumeConversationPopup.test.tsx
index c30f8d5..5359b82 100644
--- a/frontend/src/features/layout/resumeConversationPopup.test.tsx
+++ b/frontend/src/features/layout/resumeConversationPopup.test.tsx
@@ -313,4 +313,40 @@ describe("LayoutGrid — resume popup wiring (T7)", () => {
     expect(screen.queryByTestId("resume-conversation-popup")).toBeNull();
     expect(inspectConversation).not.toHaveBeenCalled();
   });
+
+  it("does not show the popup for a remounted cell whose agent was still running (#158)", async () => {
+    const layout = new MockLayoutGateway();
+    const agent = new MockAgentGateway();
+    const a = await agent.createAgent("p1", { name: "MyAgent", profileId: "p" });
+    const leafId = await seedResumeLeaf(layout, a.id);
+    await layout.mutateLayout("p1", {
+      type: "setAgentRunning",
+      target: leafId,
+      running: true,
+    });
+
+    const launchAgent = vi.fn(
+      async (
+        _p: string,
+        _ag: string,
+        _opts: OpenTerminalOptions,
+        _onData: (b: Uint8Array) => void,
+      ) => makeHandle("sess-running-resume"),
+    );
+    const inspectConversation = vi.fn();
+    const stubAgent = {
+      listAgents: () => Promise.resolve([a]),
+      launchAgent,
+      reattach: vi.fn(),
+      inspectConversation,
+    };
+
+    renderGrid(layout, stubAgent);
+
+    await waitFor(() => expect(launchAgent).toHaveBeenCalledTimes(1));
+    expect(screen.queryByTestId("resume-conversation-popup")).toBeNull();
+    expect(inspectConversation).not.toHaveBeenCalled();
+    const opts = launchAgent.mock.calls[0][2] as OpenTerminalOptions;
+    expect(opts.conversationId).toBe("prior-conv");
+  });
 });
diff --git a/frontend/src/features/projects/ProjectTabs.test.tsx b/frontend/src/features/projects/ProjectTabs.test.tsx
index 45ac3e5..e5585ec 100644
--- a/frontend/src/features/projects/ProjectTabs.test.tsx
+++ b/frontend/src/features/projects/ProjectTabs.test.tsx
@@ -7,7 +7,7 @@
  * read as faint text rather than a control.
  */
 import { describe, it, expect, vi } from "vitest";
-import { render, screen, fireEvent } from "@testing-library/react";
+import { render, screen, fireEvent, within } from "@testing-library/react";
 
 import type { TabItem } from "@/shared";
 import { ProjectTabs } from "./ProjectTabs";
@@ -27,6 +27,7 @@ function renderTabs(props: Partial<React.ComponentProps<typeof ProjectTabs>> = {
       onClose={props.onClose ?? vi.fn()}
       projectsPanelOpen={props.projectsPanelOpen ?? false}
       onOpenProjectsPanel={onOpenProjectsPanel}
+      activityByProjectId={props.activityByProjectId}
     />,
   );
   return { onOpenProjectsPanel };
@@ -74,3 +75,24 @@ describe("ProjectTabs add-project button (#46)", () => {
     expect(onOpenProjectsPanel).toHaveBeenCalledTimes(1);
   });
 });
+
+describe("ProjectTabs project activity dots (#159)", () => {
+  it("renders the neutral activity dot to the left of a project name by default", () => {
+    renderTabs({ items: TABS });
+
+    const tab = screen.getByRole("tab", { name: /alpha/ });
+    expect(
+      within(tab).getByTitle("alpha : aucune conversation active"),
+    ).toBeTruthy();
+  });
+
+  it("renders idle and busy project activity states", () => {
+    renderTabs({
+      items: TABS,
+      activityByProjectId: { a: "idle", b: "busy" },
+    });
+
+    expect(screen.getByTitle("alpha : conversation ouverte")).toBeTruthy();
+    expect(screen.getByTitle("beta : activité en cours")).toBeTruthy();
+  });
+});
diff --git a/frontend/src/features/projects/ProjectTabs.tsx b/frontend/src/features/projects/ProjectTabs.tsx
index 3cbdc97..468e54d 100644
--- a/frontend/src/features/projects/ProjectTabs.tsx
+++ b/frontend/src/features/projects/ProjectTabs.tsx
@@ -12,6 +12,7 @@
 
 import type { TabItem } from "@/shared";
 import { Button, Tabs, cn } from "@/shared";
+import type { ProjectActivityStatus } from "./projectActivity";
 
 export interface ProjectTabsProps {
   items: TabItem[];
@@ -22,6 +23,8 @@ export interface ProjectTabsProps {
   projectsPanelOpen: boolean;
   /** Open the Projects panel (floating) — create/switch project. */
   onOpenProjectsPanel: () => void;
+  /** Per-project custom CLI activity, keyed by project id. Missing = none. */
+  activityByProjectId?: Record<string, ProjectActivityStatus>;
   className?: string;
 }
 
@@ -32,8 +35,19 @@ export function ProjectTabs({
   onClose,
   projectsPanelOpen,
   onOpenProjectsPanel,
+  activityByProjectId = {},
   className,
 }: ProjectTabsProps) {
+  const tabs = items.map((item) => ({
+    ...item,
+    leading: (
+      <ProjectActivityDot
+        status={activityByProjectId[item.id] ?? "none"}
+        label={item.label}
+      />
+    ),
+  }));
+
   return (
     <div
       className={cn(
@@ -45,7 +59,7 @@ export function ProjectTabs({
         <p className="px-2 text-sm text-muted">No open tabs.</p>
       ) : (
         <Tabs
-          items={items}
+          items={tabs}
           value={activeTabId}
           onSelect={onSelect}
           onClose={onClose}
@@ -72,3 +86,32 @@ export function ProjectTabs({
     </div>
   );
 }
+
+function ProjectActivityDot({
+  status,
+  label,
+}: {
+  status: ProjectActivityStatus;
+  label: string;
+}) {
+  const title =
+    status === "busy"
+      ? `${label} : activité en cours`
+      : status === "idle"
+        ? `${label} : conversation ouverte`
+        : `${label} : aucune conversation active`;
+  return (
+    <span
+      data-testid={`project-activity-${label}`}
+      aria-hidden="true"
+      title={title}
+      className={cn(
+        "h-2.5 w-2.5 shrink-0 rounded-full border",
+        status === "busy" &&
+          "animate-pulse border-warning bg-warning shadow-[0_0_0_2px_rgba(212,155,58,0.16)]",
+        status === "idle" && "border-success bg-success",
+        status === "none" && "border-border-strong bg-muted",
+      )}
+    />
+  );
+}
diff --git a/frontend/src/features/projects/ProjectsView.tsx b/frontend/src/features/projects/ProjectsView.tsx
index b89ccf8..5a51c4e 100644
--- a/frontend/src/features/projects/ProjectsView.tsx
+++ b/frontend/src/features/projects/ProjectsView.tsx
@@ -70,6 +70,7 @@ import {
 } from "@/shared";
 import { useGateways } from "@/app/di";
 import { useProjects } from "./useProjects";
+import { useProjectActivity } from "./useProjectActivity";
 import { ProjectTabs } from "./ProjectTabs";
 import { ViewPanelBody, type ViewPanelId } from "./ViewPanelBody";
 import {
@@ -201,6 +202,7 @@ function rendezvousToastStateLabel(state: string): string {
 
 export function ProjectsView() {
   const vm = useProjects();
+  const projectActivity = useProjectActivity(vm.openTabs.map((tab) => tab.id));
   const {
     system,
     window: windowGateway,
@@ -859,6 +861,7 @@ export function ProjectsView() {
         activeTabId={vm.activeTabId}
         onSelect={(id) => vm.activateTab(id)}
         onClose={(id) => void vm.closeTab(id)}
+        activityByProjectId={projectActivity}
         projectsPanelOpen={placementOf(placements, "projects") !== "closed"}
         onOpenProjectsPanel={() => {
           setSettingsSection(null);
diff --git a/frontend/src/features/projects/projectActivity.test.ts b/frontend/src/features/projects/projectActivity.test.ts
new file mode 100644
index 0000000..f957ac1
--- /dev/null
+++ b/frontend/src/features/projects/projectActivity.test.ts
@@ -0,0 +1,76 @@
+import { describe, expect, it } from "vitest";
+
+import { projectActivityStatus } from "./projectActivity";
+
+describe("projectActivityStatus (#159)", () => {
+  it("is none when no custom CLI conversation is visible in the work-state", () => {
+    expect(projectActivityStatus({ agents: [], conversations: [] })).toBe("none");
+  });
+
+  it("is idle when a structured custom CLI session has a conversation but no work", () => {
+    expect(
+      projectActivityStatus({
+        agents: [
+          {
+            agentId: "a1",
+            name: "A",
+            profileId: "p",
+            live: { kind: "structured", nodeId: "n1", sessionId: "s1" },
+            busy: { state: "idle" },
+            tickets: [],
+          },
+        ],
+        conversations: [],
+      }),
+    ).toBe("idle");
+  });
+
+  it("is busy when any agent is busy", () => {
+    expect(
+      projectActivityStatus({
+        agents: [
+          {
+            agentId: "a1",
+            name: "A",
+            profileId: "p",
+            busy: { state: "busy", ticket: "ticket-1", sinceMs: 1 },
+            tickets: [],
+          },
+        ],
+        conversations: [],
+      }),
+    ).toBe("busy");
+  });
+
+  it("is busy for running or pending background work tied to a conversation", () => {
+    expect(
+      projectActivityStatus({
+        agents: [
+          {
+            agentId: "a1",
+            name: "A",
+            profileId: "p",
+            busy: { state: "idle" },
+            tickets: [],
+            backgroundTasks: [
+              {
+                taskId: "t1",
+                ownerAgentId: "a1",
+                projectId: "p1",
+                kind: "command",
+                status: "running",
+                exitCode: null,
+                summary: null,
+                stdoutTail: null,
+                stderrTail: null,
+                conversationId: "c1",
+                updatedAtMs: 1,
+              },
+            ],
+          },
+        ],
+        conversations: [],
+      }),
+    ).toBe("busy");
+  });
+});
diff --git a/frontend/src/features/projects/projectActivity.ts b/frontend/src/features/projects/projectActivity.ts
new file mode 100644
index 0000000..fcf7db3
--- /dev/null
+++ b/frontend/src/features/projects/projectActivity.ts
@@ -0,0 +1,34 @@
+import type { BackgroundCompletion, ProjectWorkState } from "@/domain";
+
+export type ProjectActivityStatus = "none" | "idle" | "busy";
+
+const ACTIVE_BACKGROUND_STATUSES: ReadonlySet<BackgroundCompletion["status"]> =
+  new Set(["pending", "running"]);
+
+export function projectActivityStatus(
+  state: ProjectWorkState | null | undefined,
+): ProjectActivityStatus {
+  if (!state) return "none";
+
+  const hasBusyAgent = state.agents.some((agent) => {
+    if (agent.busy.state === "busy") return true;
+    if (agent.tickets.some((ticket) => ticket.status === "inProgress")) return true;
+    return (agent.backgroundTasks ?? []).some((task) =>
+      ACTIVE_BACKGROUND_STATUSES.has(task.status),
+    );
+  });
+  if (hasBusyAgent) return "busy";
+
+  const hasConversation = state.conversations.length > 0 ||
+    state.agents.some((agent) => {
+      if (agent.live?.kind === "structured") return true;
+      if (agent.tickets.some((ticket) => ticket.conversationId.trim() !== "")) {
+        return true;
+      }
+      return (agent.backgroundTasks ?? []).some(
+        (task) => task.conversationId?.trim(),
+      );
+    });
+
+  return hasConversation ? "idle" : "none";
+}
diff --git a/frontend/src/features/projects/useProjectActivity.ts b/frontend/src/features/projects/useProjectActivity.ts
new file mode 100644
index 0000000..64d797a
--- /dev/null
+++ b/frontend/src/features/projects/useProjectActivity.ts
@@ -0,0 +1,84 @@
+import { useCallback, useEffect, useMemo, useState } from "react";
+
+import type { ProjectWorkState } from "@/domain";
+import { useGateways } from "@/app/di";
+import {
+  projectActivityStatus,
+  type ProjectActivityStatus,
+} from "./projectActivity";
+
+export type ProjectActivityMap = Record<string, ProjectActivityStatus>;
+
+const REFRESH_EVENTS = new Set([
+  "agentLaunched",
+  "agentExited",
+  "agentBusyChanged",
+  "delegationReady",
+  "orchestratorRequestProcessed",
+  "backgroundTaskChanged",
+  "agentInboxChanged",
+  "agentWakeChanged",
+]);
+
+export function useProjectActivity(projectIds: string[]): ProjectActivityMap {
+  const { system, workState } = useGateways();
+  const projectKey = [...new Set(projectIds)].sort().join("\0");
+  const stableProjectIds = useMemo(
+    () => [...new Set(projectIds)].sort(),
+    // eslint-disable-next-line react-hooks/exhaustive-deps
+    [projectKey],
+  );
+  const [states, setStates] = useState<Record<string, ProjectWorkState | null>>(
+    {},
+  );
+
+  const refresh = useCallback(async () => {
+    if (stableProjectIds.length === 0) {
+      setStates({});
+      return;
+    }
+    const entries = await Promise.all(
+      stableProjectIds.map(async (projectId) => {
+        try {
+          return [
+            projectId,
+            await workState.getProjectWorkState(projectId),
+          ] as const;
+        } catch {
+          return [projectId, null] as const;
+        }
+      }),
+    );
+    setStates(Object.fromEntries(entries));
+  }, [stableProjectIds, workState]);
+
+  useEffect(() => {
+    void refresh();
+  }, [refresh]);
+
+  useEffect(() => {
+    if (!system) return;
+    let unsubscribe: (() => void) | undefined;
+    let cancelled = false;
+    void system
+      .onDomainEvent((event) => {
+        if (REFRESH_EVENTS.has(event.type)) void refresh();
+      })
+      .then((un) => {
+        if (cancelled) un();
+        else unsubscribe = un;
+      });
+    return () => {
+      cancelled = true;
+      unsubscribe?.();
+    };
+  }, [refresh, system]);
+
+  return useMemo(() => {
+    const next: ProjectActivityMap = {};
+    for (const projectId of stableProjectIds) {
+      next[projectId] = projectActivityStatus(states[projectId]);
+    }
+    return next;
+  }, [stableProjectIds, states]);
+}
diff --git a/frontend/src/shared/ui/Tabs.tsx b/frontend/src/shared/ui/Tabs.tsx
index b1651d8..a6bdf4b 100644
--- a/frontend/src/shared/ui/Tabs.tsx
+++ b/frontend/src/shared/ui/Tabs.tsx
@@ -7,12 +7,15 @@
 
 import { cn } from "../lib/cn";
 import { IconButton } from "./IconButton";
+import type { ReactNode } from "react";
 
 export interface TabItem {
   /** Stable id, returned by `onSelect`/`onClose`. */
   id: string;
   /** Visible label. */
   label: string;
+  /** Optional leading visual, such as a status indicator. */
+  leading?: ReactNode;
 }
 
 export interface TabsProps {
@@ -52,11 +55,12 @@ export function Tabs({ items, value, onSelect, onClose, className }: TabsProps)
               aria-selected={active}
               onClick={() => onSelect(tab.id)}
               className={cn(
-                "px-2 py-1 text-sm focus-visible:outline-none",
+                "flex items-center gap-1.5 px-2 py-1 text-sm focus-visible:outline-none",
                 active ? "font-semibold text-content" : "text-muted hover:text-content",
               )}
             >
-              {tab.label}
+              {tab.leading}
+              <span>{tab.label}</span>
             </button>
             {onClose && (
               <IconButton