diff --git a/src/client/src/components/PiWebApp.ts b/src/client/src/components/PiWebApp.ts
index b1d6394..4e4d01f 100644
--- a/src/client/src/components/PiWebApp.ts
+++ b/src/client/src/components/PiWebApp.ts
@@ -27,6 +27,7 @@ import { sessionCleanupRequestKey, sessionCleanupUnavailableMessage } from "../s
 import { selectedNotificationView } from "../sessionNotifications";
 import { hasAuthoritativeSessionPersistence as runtimeHasAuthoritativeSessionPersistence } from "../sessionPersistence";
 import { SessionUnreadController } from "../sessionUnread";
+import { deriveUnreadPresence, EMPTY_UNREAD_PRESENCE, sameUnreadPresence, type UnreadPresence } from "../unreadPresence";
 import { initialSessionWarningVisibilityState, reconcileSessionWarningVisibility, toggleSessionWarnings } from "../sessionWarningVisibility";
 import { RealtimeSocket, type BrowserRealtimeEvent } from "../sessionSocket";
 import type { PiWebPluginRegistration, PluginMachine, PluginPromptEditor, QualifiedContributionId, QualifiedThemeContribution, QualifiedThemePairContribution, QualifiedWorkspacePanelContribution, PluginRuntimeContext, TerminalCommandRunsInternalRuntime, WorkspaceFiles, WorkspaceHost, WorkspaceLabelContext, WorkspaceLabelItem, WorkspacePanelContext } from "../plugins/types";
@@ -109,6 +110,7 @@ export class PiWebApp extends LitElement {
 
   private readonly sessionUnread = new SessionUnreadController({
     onChange: (machineId) => {
+      this.syncUnreadPresence();
       if (selectedMachineId(this.state) !== machineId) return;
       this.syncUnreadSessionIds();
       this.syncSelectedSessionReadState();
@@ -118,6 +120,7 @@ export class PiWebApp extends LitElement {
     },
   });
   @state() private unreadSessionIds: ReadonlySet<string> = this.sessionUnread.unreadSessionIds(selectedMachineId(this.state), this.state.sessions);
+  @state() private unreadPresence: UnreadPresence = EMPTY_UNREAD_PRESENCE;
   private unreadConnected = false;
   private committedChatIdentity: string | undefined;
   private readyChatIdentity: string | undefined;
@@ -319,6 +322,18 @@ export class PiWebApp extends LitElement {
     if (!sameStringSet(next, this.unreadSessionIds)) this.unreadSessionIds = next;
   }
 
+  private syncUnreadPresence(): void {
+    const next = deriveUnreadPresence({
+      machineIds: this.state.machines.map((machine) => machine.id),
+      projectionFor: (machineId) => this.sessionUnread.projection(machineId),
+      selectedMachineId: selectedMachineId(this.state),
+      projects: this.state.projects,
+      workspaces: this.state.workspaces,
+      workspacesByProjectId: this.state.workspacesByProjectId,
+    });
+    if (!sameUnreadPresence(next, this.unreadPresence)) this.unreadPresence = next;
+  }
+
   private isSessionSeen(machineId: string, session: SessionInfo): boolean {
     if (!this.unreadConnected) return false;
     const identity = unreadChatIdentity(machineId, session);
@@ -404,6 +419,7 @@ export class PiWebApp extends LitElement {
     }
     if (machineUnreadInputsChanged(previous, this.state)) this.syncSessionUnreadMachines();
     this.syncUnreadSessionIds();
+    this.syncUnreadPresence();
     this.handleActivityTransition(previous, this.state);
     this.handleWorkspaceChange(previous, this.state);
     this.handleMachineChange(previous, this.state);
diff --git a/src/client/src/components/PiWebApp.unread.test.ts b/src/client/src/components/PiWebApp.unread.test.ts
index 208aff1..e6a746e 100644
--- a/src/client/src/components/PiWebApp.unread.test.ts
+++ b/src/client/src/components/PiWebApp.unread.test.ts
@@ -1,9 +1,10 @@
 import type { TemplateResult } from "lit";
 import { afterEach, describe, expect, it, vi } from "vitest";
 import { PI_WEB_CAPABILITIES } from "../../../shared/capabilities";
-import type { SessionInfo, SessionUnreadEvent, SessionUnreadSummary } from "../api";
+import type { Machine, Project, SessionInfo, SessionUnreadEvent, SessionUnreadSummary, Workspace } from "../api";
 import { initialAppState, type AppState } from "../appState";
 import type { BrowserRealtimeEvent } from "../sessionSocket";
+import type { UnreadPresence } from "../unreadPresence";
 import type { AppMobileMainTab } from "./appShell/AppMobileMainTabs";
 // Template inspection is proportionate here because this node-environment test
 // verifies only PiWebApp's unread-state property wiring into navigation.
@@ -277,11 +278,71 @@ describe("PiWebApp session unread wiring", () => {
     expect(requests).toContain("https://pi.example.test/api/machines/local/sessions/beta/unread/acknowledge");
     await vi.waitFor(() => { expect(navigationUnreadSessionIds(app).size).toBe(0); });
   });
+
+  it("derives bubble-up unread presence for selected and background machines", () => {
+    stubJsonFetch({ catalogId: "catalog-a", catalogRevision: 2, sessions: [] });
+    const app = createApp();
+    enableUnread(app);
+    enableUnreadMachine(app, "remote");
+    const selected = session("selected");
+    setAppState(app, {
+      ...initialAppState(),
+      machines: [machine("local"), machine("remote")],
+      selectedMachine: machine("local"),
+      projects: [project("project-1")],
+      workspaces: [workspace("ws-1", "project-1", "/repo")],
+      workspacesByProjectId: { "project-1": [workspace("ws-1", "project-1", "/repo")] },
+      sessions: [selected],
+      selectedSession: selected,
+      mainView: "chat",
+    });
+
+    handleRealtimeEvent(app, unreadEvent(1, unreadSummary(selected, 1)));
+    expect([...unreadPresence(app).machines]).toEqual(["local"]);
+    expect([...unreadPresence(app).projects]).toEqual(["project-1"]);
+    expect([...unreadPresence(app).workspaces]).toEqual(["ws-1"]);
+
+    const remoteSession = { ...session("remote-session"), cwd: "/unmapped" };
+    handleMachineActivityEvent(app, "remote", unreadEvent(1, unreadSummary(remoteSession, 1)));
+    expect([...unreadPresence(app).machines].sort()).toEqual(["local", "remote"]);
+    // Background cwds never leak into the selected machine's workspace/project rows.
+    expect([...unreadPresence(app).projects]).toEqual(["project-1"]);
+    expect([...unreadPresence(app).workspaces]).toEqual(["ws-1"]);
+  });
+
+  it("recomputes bubble-up presence when workspace data loads after the unread event", () => {
+    stubJsonFetch({ catalogId: "catalog-a", catalogRevision: 2, sessions: [] });
+    const app = createApp();
+    enableUnread(app);
+    const selected = session("selected");
+    setAppState(app, {
+      ...initialAppState(),
+      machines: [machine("local")],
+      selectedMachine: machine("local"),
+      sessions: [selected],
+      selectedSession: selected,
+      mainView: "chat",
+    });
+
+    handleRealtimeEvent(app, unreadEvent(1, unreadSummary(selected, 1)));
+    expect([...unreadPresence(app).machines]).toEqual(["local"]);
+    expect(unreadPresence(app).projects.size).toBe(0);
+    expect(unreadPresence(app).workspaces.size).toBe(0);
+
+    setState(app, {
+      projects: [project("project-1")],
+      workspaces: [workspace("ws-1", "project-1", "/repo")],
+      workspacesByProjectId: { "project-1": [workspace("ws-1", "project-1", "/repo")] },
+    });
+    expect([...unreadPresence(app).projects]).toEqual(["project-1"]);
+    expect([...unreadPresence(app).workspaces]).toEqual(["ws-1"]);
+  });
 });
 
 type RenderNavigationPanel = (this: PiWebApp) => TemplateResult;
 type SetAppState = (this: PiWebApp, patch: Partial<AppState>) => void;
 type HandleRealtimeEvent = (this: PiWebApp, machineId: string, event: BrowserRealtimeEvent) => void;
+type HandleMachineActivityEvent = (this: PiWebApp, machineId: string, event: BrowserRealtimeEvent) => void;
 type MobileMainTabs = (this: PiWebApp) => AppMobileMainTab[];
 type UpdatedHook = (this: PiWebApp) => void;
 type DisconnectedHook = (this: PiWebApp) => void;
@@ -335,13 +396,23 @@ function handleRealtimeEvent(app: PiWebApp, event: BrowserRealtimeEvent): void {
   method.call(app, "local", event);
 }
 
+function handleMachineActivityEvent(app: PiWebApp, machineId: string, event: BrowserRealtimeEvent): void {
+  const method: unknown = Reflect.get(app, "handleMachineActivityEvent");
+  if (!isHandleMachineActivityEvent(method)) throw new Error("PiWebApp.handleMachineActivityEvent is not callable");
+  method.call(app, machineId, event);
+}
+
 function enableUnread(app: PiWebApp): void {
   if (!Reflect.set(app, "unreadConnected", true)) throw new Error("Could not connect PiWebApp unread state");
+  enableUnreadMachine(app, "local");
+}
+
+function enableUnreadMachine(app: PiWebApp, machineId: string): void {
   const controller: unknown = Reflect.get(app, "sessionUnread");
   if (typeof controller !== "object" || controller === null) throw new Error("PiWebApp unread controller is unavailable");
   const setCapability: unknown = Reflect.get(controller, "setCapability");
   if (typeof setCapability !== "function") throw new Error("PiWebApp unread capability setter is unavailable");
-  Reflect.apply(setCapability, controller, ["local", "supported"]);
+  Reflect.apply(setCapability, controller, [machineId, "supported"]);
 }
 
 function exposeSelectedChat(app: PiWebApp): void {
@@ -429,6 +500,37 @@ function navigationPanelValue(app: PiWebApp, marker: string): unknown {
   return templateValueAfterMarker(method.call(app), marker);
 }
 
+function unreadPresence(app: PiWebApp): UnreadPresence {
+  const value: unknown = Reflect.get(app, "unreadPresence");
+  if (!isUnreadPresence(value)) throw new Error("Expected derived unread presence on PiWebApp");
+  return value;
+}
+
+function isUnreadPresence(value: unknown): value is UnreadPresence {
+  if (typeof value !== "object" || value === null) return false;
+  return Reflect.get(value, "machines") instanceof Set
+    && Reflect.get(value, "projects") instanceof Set
+    && Reflect.get(value, "workspaces") instanceof Set;
+}
+
+function machine(id: string): Machine {
+  return {
+    id,
+    name: id,
+    kind: id === "local" ? "local" : "remote",
+    createdAt: "2026-07-20T00:00:00.000Z",
+    updatedAt: "2026-07-20T00:00:00.000Z",
+  };
+}
+
+function project(id: string): Project {
+  return { id, name: id, path: "/repo", createdAt: "2026-07-20T00:00:00.000Z" };
+}
+
+function workspace(id: string, projectId: string, path: string): Workspace {
+  return { id, projectId, path, label: id, isMain: true, isGitRepo: true, isGitWorktree: false };
+}
+
 function session(id: string): SessionInfo {
   return {
     id,
@@ -502,6 +604,10 @@ function isHandleRealtimeEvent(value: unknown): value is HandleRealtimeEvent {
   return typeof value === "function";
 }
 
+function isHandleMachineActivityEvent(value: unknown): value is HandleMachineActivityEvent {
+  return typeof value === "function";
+}
+
 function isMobileMainTabs(value: unknown): value is MobileMainTabs {
   return typeof value === "function";
 }
diff --git a/src/client/src/unreadPresence.test.ts b/src/client/src/unreadPresence.test.ts
new file mode 100644
index 0000000..4298da8
--- /dev/null
+++ b/src/client/src/unreadPresence.test.ts
@@ -0,0 +1,184 @@
+import { describe, expect, it } from "vitest";
+import type { Project, SessionUnreadSummary, Workspace } from "../../shared/apiTypes";
+import type { SessionUnreadProjectionView } from "./sessionUnread";
+import {
+  deriveUnreadPresence,
+  EMPTY_UNREAD_PRESENCE,
+  hasUnreadSessions,
+  machineUnreadPresence,
+  projectUnreadPresence,
+  sameUnreadPresence,
+  unreadCwds,
+  workspaceUnreadPresence,
+  type UnreadPresenceInputs,
+} from "./unreadPresence";
+
+describe("hasUnreadSessions", () => {
+  it("treats an unavailable projection as no presence", () => {
+    expect(hasUnreadSessions(undefined)).toBe(false);
+  });
+
+  it("treats an empty projection as no presence", () => {
+    expect(hasUnreadSessions(projection())).toBe(false);
+  });
+
+  it("treats any summary as presence, even when the projection is stale", () => {
+    expect(hasUnreadSessions(projection([summary("session-1", "/repo")]))).toBe(true);
+    expect(hasUnreadSessions(projection([summary("session-1", "/repo")], "stale"))).toBe(true);
+  });
+});
+
+describe("unreadCwds", () => {
+  it("is empty without a projection or without sessions", () => {
+    expect([...unreadCwds(undefined)]).toEqual([]);
+    expect([...unreadCwds(projection())]).toEqual([]);
+  });
+
+  it("collects the distinct cwds of unread summaries", () => {
+    const cwds = unreadCwds(projection([
+      summary("session-1", "/repo", 2),
+      summary("session-2", "/repo", 1),
+      summary("session-3", "/other", 3),
+    ]));
+    expect([...cwds].sort()).toEqual(["/other", "/repo"]);
+  });
+});
+
+describe("machineUnreadPresence", () => {
+  it("flags machines with any unread summary, including cwds mapped to no known workspace", () => {
+    const projections = new Map<string, SessionUnreadProjectionView | undefined>([
+      ["local", projection([summary("session-1", "/unmapped")])],
+      ["empty", projection()],
+      ["unsupported", undefined],
+    ]);
+    const present = machineUnreadPresence(["local", "empty", "unsupported"], (machineId) => projections.get(machineId));
+    expect([...present]).toEqual(["local"]);
+  });
+
+  it("only considers the listed machine ids", () => {
+    const present = machineUnreadPresence(["local"], () => projection([summary("session-1", "/repo")]));
+    expect([...present]).toEqual(["local"]);
+  });
+});
+
+describe("workspaceUnreadPresence", () => {
+  it("flags the workspace whose path exactly matches an unread cwd", () => {
+    const workspaces = [workspace("ws-1", "project-1", "/repo"), workspace("ws-2", "project-1", "/repo/branch")];
+    expect([...workspaceUnreadPresence(workspaces, new Set(["/repo/branch"]))]).toEqual(["ws-2"]);
+  });
+
+  it("flags nothing when no unread cwd maps to a workspace path", () => {
+    const workspaces = [workspace("ws-1", "project-1", "/repo")];
+    expect([...workspaceUnreadPresence(workspaces, new Set(["/unmapped"]))]).toEqual([]);
+    expect([...workspaceUnreadPresence(workspaces, new Set())]).toEqual([]);
+  });
+});
+
+describe("projectUnreadPresence", () => {
+  it("flags the project owning a workspace with an unread cwd", () => {
+    const projects = [project("project-1"), project("project-2")];
+    const workspacesByProjectId = {
+      "project-1": [workspace("ws-1", "project-1", "/repo")],
+      "project-2": [workspace("ws-2", "project-2", "/other")],
+    };
+    expect([...projectUnreadPresence(projects, workspacesByProjectId, new Set(["/other"]))]).toEqual(["project-2"]);
+  });
+
+  it("flags the project through its main workspace at the project path", () => {
+    const projects = [project("project-1", "/repo")];
+    const workspacesByProjectId = { "project-1": [workspace("ws-1", "project-1", "/repo")] };
+    expect([...projectUnreadPresence(projects, workspacesByProjectId, new Set(["/repo"]))]).toEqual(["project-1"]);
+  });
+
+  it("does not flag a project whose workspaces are not loaded", () => {
+    const projects = [project("project-1")];
+    expect([...projectUnreadPresence(projects, {}, new Set(["/repo"]))]).toEqual([]);
+  });
+
+  it("leaves a cwd under the project path but matching no known workspace to the machine dot only", () => {
+    const projects = [project("project-1", "/repo")];
+    const workspacesByProjectId = { "project-1": [workspace("ws-1", "project-1", "/repo/main")] };
+    expect([...projectUnreadPresence(projects, workspacesByProjectId, new Set(["/repo/unmapped-subdir"]))]).toEqual([]);
+  });
+});
+
+describe("deriveUnreadPresence", () => {
+  it("maps the selected machine's unread cwds to workspace and project presence", () => {
+    const inputs = presenceInputs({
+      projections: new Map([["local", projection([summary("session-1", "/repo")])]]),
+    });
+
+    const presence = deriveUnreadPresence(inputs);
+
+    expect([...presence.machines]).toEqual(["local"]);
+    expect([...presence.workspaces]).toEqual(["ws-1"]);
+    expect([...presence.projects]).toEqual(["project-1"]);
+  });
+
+  it("reflects background machines at machine level without leaking their cwds into workspace or project rows", () => {
+    const inputs = presenceInputs({
+      machineIds: ["local", "remote"],
+      projections: new Map([
+        ["local", projection()],
+        ["remote", projection([summary("session-1", "/repo")])],
+      ]),
+    });
+
+    const presence = deriveUnreadPresence(inputs);
+
+    expect([...presence.machines]).toEqual(["remote"]);
+    expect([...presence.workspaces]).toEqual([]);
+    expect([...presence.projects]).toEqual([]);
+  });
+
+  it("is empty when no machine has a usable projection", () => {
+    const presence = deriveUnreadPresence(presenceInputs({ projections: new Map([["local", undefined]]) }));
+    expect(sameUnreadPresence(presence, EMPTY_UNREAD_PRESENCE)).toBe(true);
+  });
+});
+
+describe("sameUnreadPresence", () => {
+  it("compares presence by set contents", () => {
+    const left = { machines: new Set(["local"]), projects: new Set(["project-1"]), workspaces: new Set(["ws-1"]) };
+    const matching = { machines: new Set(["local"]), projects: new Set(["project-1"]), workspaces: new Set(["ws-1"]) };
+    const different = { machines: new Set(["remote"]), projects: new Set(["project-1"]), workspaces: new Set(["ws-1"]) };
+    expect(sameUnreadPresence(left, matching)).toBe(true);
+    expect(sameUnreadPresence(left, different)).toBe(false);
+    expect(sameUnreadPresence(EMPTY_UNREAD_PRESENCE, { machines: new Set(), projects: new Set(), workspaces: new Set() })).toBe(true);
+  });
+});
+
+function presenceInputs(options: {
+  machineIds?: string[];
+  projections: Map<string, SessionUnreadProjectionView | undefined>;
+}): UnreadPresenceInputs {
+  return {
+    machineIds: options.machineIds ?? ["local"],
+    projectionFor: (machineId) => options.projections.get(machineId),
+    selectedMachineId: "local",
+    projects: [project("project-1", "/repo")],
+    workspaces: [workspace("ws-1", "project-1", "/repo")],
+    workspacesByProjectId: { "project-1": [workspace("ws-1", "project-1", "/repo")] },
+  };
+}
+
+function summary(sessionId: string, cwd: string, completionOrder = 1): SessionUnreadSummary {
+  return { sessionId, cwd, completionOrder, completedAt: "2026-07-20T00:00:00.000Z" };
+}
+
+function projection(summaries: SessionUnreadSummary[] = [], status: "fresh" | "stale" = "fresh"): SessionUnreadProjectionView {
+  return {
+    status,
+    catalogId: "catalog-a",
+    catalogRevision: summaries.reduce((revision, entry) => Math.max(revision, entry.completionOrder), 0),
+    sessions: summaries,
+  };
+}
+
+function workspace(id: string, projectId: string, path: string): Workspace {
+  return { id, projectId, path, label: id, isMain: false, isGitRepo: true, isGitWorktree: false };
+}
+
+function project(id: string, path = `/${id}`): Project {
+  return { id, name: id, path, createdAt: "2026-07-20T00:00:00.000Z" };
+}
diff --git a/src/client/src/unreadPresence.ts b/src/client/src/unreadPresence.ts
new file mode 100644
index 0000000..20b48e5
--- /dev/null
+++ b/src/client/src/unreadPresence.ts
@@ -0,0 +1,106 @@
+import type { Project, Workspace } from "./api";
+import type { SessionUnreadProjectionView } from "./sessionUnread";
+
+/**
+ * Bubble-up unread *presence* (booleans, never counts) derived from
+ * `SessionUnreadController` projections, following the charter mapping chain
+ * cwd → workspace → project → machine:
+ *
+ * - A machine has presence when its projection carries ANY unread summary,
+ *   including cwds that map to no known workspace — the honest catch-all.
+ * - A workspace has presence when an unread cwd equals its path exactly.
+ * - A project has presence only when one of its known workspaces has presence;
+ *   a cwd matching no known workspace lights the machine dot only, never a
+ *   project or workspace row (even when it sits under the project path).
+ * - An undefined projection (unsupported/unknown capability or not yet
+ *   loaded) yields no presence. Stale-but-present data still counts, the same
+ *   tolerance `SessionUnreadController.unreadSessionIds` applies.
+ *
+ * Workspace/project presence can only be derived for the machine whose
+ * projects and workspaces are loaded — the selected one.
+ */
+
+export interface UnreadPresence {
+  readonly machines: ReadonlySet<string>;
+  readonly projects: ReadonlySet<string>;
+  readonly workspaces: ReadonlySet<string>;
+}
+
+/** Shared empty value; consumers must treat it as immutable. */
+export const EMPTY_UNREAD_PRESENCE: UnreadPresence = {
+  machines: new Set(),
+  projects: new Set(),
+  workspaces: new Set(),
+};
+
+export interface UnreadPresenceInputs {
+  readonly machineIds: readonly string[];
+  readonly projectionFor: (machineId: string) => SessionUnreadProjectionView | undefined;
+  readonly selectedMachineId: string;
+  readonly projects: readonly Project[];
+  /** Visible workspace rows (the selected project's workspaces). */
+  readonly workspaces: readonly Workspace[];
+  readonly workspacesByProjectId: Record<string, readonly Workspace[]>;
+}
+
+export function deriveUnreadPresence(input: UnreadPresenceInputs): UnreadPresence {
+  const cwds = unreadCwds(input.projectionFor(input.selectedMachineId));
+  return {
+    machines: machineUnreadPresence(input.machineIds, input.projectionFor),
+    projects: projectUnreadPresence(input.projects, input.workspacesByProjectId, cwds),
+    workspaces: workspaceUnreadPresence(input.workspaces, cwds),
+  };
+}
+
+export function hasUnreadSessions(projection: Pick<SessionUnreadProjectionView, "sessions"> | undefined): boolean {
+  return projection !== undefined && projection.sessions.length > 0;
+}
+
+export function unreadCwds(projection: Pick<SessionUnreadProjectionView, "sessions"> | undefined): ReadonlySet<string> {
+  if (projection === undefined || projection.sessions.length === 0) return EMPTY_CWDS;
+  return new Set(projection.sessions.map((summary) => summary.cwd));
+}
+
+export function machineUnreadPresence(
+  machineIds: readonly string[],
+  projectionFor: (machineId: string) => SessionUnreadProjectionView | undefined,
+): ReadonlySet<string> {
+  const present = new Set<string>();
+  for (const machineId of machineIds) {
+    if (hasUnreadSessions(projectionFor(machineId))) present.add(machineId);
+  }
+  return present;
+}
+
+export function workspaceUnreadPresence(workspaces: readonly Workspace[], cwds: ReadonlySet<string>): ReadonlySet<string> {
+  const present = new Set<string>();
+  for (const workspace of workspaces) {
+    if (cwds.has(workspace.path)) present.add(workspace.id);
+  }
+  return present;
+}
+
+export function projectUnreadPresence(
+  projects: readonly Project[],
+  workspacesByProjectId: Record<string, readonly Workspace[]>,
+  cwds: ReadonlySet<string>,
+): ReadonlySet<string> {
+  const present = new Set<string>();
+  for (const project of projects) {
+    const workspaces = workspacesByProjectId[project.id] ?? [];
+    if (workspaces.some((workspace) => cwds.has(workspace.path))) present.add(project.id);
+  }
+  return present;
+}
+
+export function sameUnreadPresence(left: UnreadPresence, right: UnreadPresence): boolean {
+  return sameStringSet(left.machines, right.machines)
+    && sameStringSet(left.projects, right.projects)
+    && sameStringSet(left.workspaces, right.workspaces);
+}
+
+const EMPTY_CWDS: ReadonlySet<string> = new Set();
+
+function sameStringSet(left: ReadonlySet<string>, right: ReadonlySet<string>): boolean {
+  return left.size === right.size && [...left].every((value) => right.has(value));
+}