diff --git a/packages/junior-dashboard/src/client/conversations/ConversationHomeList.tsx b/packages/junior-dashboard/src/client/conversations/ConversationHomeList.tsx
index 17c4103aea..a5f909af9b 100644
--- a/packages/junior-dashboard/src/client/conversations/ConversationHomeList.tsx
+++ b/packages/junior-dashboard/src/client/conversations/ConversationHomeList.tsx
@@ -1,5 +1,5 @@
 import { useCallback, useState } from "react";
-import { Archive, ArchiveRestore, LockKeyhole } from "lucide-react";
+import { Archive, ArchiveRestore } from "lucide-react";
 import { Link } from "react-router";
 
 import {
@@ -9,7 +9,6 @@ import {
   slackLocationLabel,
   visualStatusForConversation,
 } from "../format";
-import { ActiveIndicator } from "../components/ActiveIndicator";
 import { EmptyTelemetry } from "../components/EmptyTelemetry";
 import { Skeleton } from "../components/Skeleton";
 import { cn } from "../styles";
@@ -17,6 +16,7 @@ import type { Conversation } from "../types";
 import { ConversationSidebarAnnotations } from "./ConversationMeta";
 import { formatConversationActivityPreview } from "./conversationActivityPreview";
 import { ConversationArchiveNotices } from "./ConversationArchiveNotices";
+import { ConversationListStatusIcon } from "./ConversationListStatusIcon";
 import { conversationPath } from "./conversationRoutes";
 import { useArchiveConversation } from "./queries";
 import {
@@ -28,6 +28,7 @@ import {
 export function ConversationHomeList(props: {
   conversations: Conversation[];
   emptyLabel?: string;
+  finishedConversationIds: ReadonlySet<string>;
   loading?: boolean;
   timeZone: string;
 }) {
@@ -85,6 +86,7 @@ export function ConversationHomeList(props: {
       <div aria-label="Your conversations" className="grid gap-5" role="list">
         {sections.map((section) => (
           <ConversationCardSection
+            finishedConversationIds={props.finishedConversationIds}
             key={section.key}
             onArchiveError={handleArchiveError}
             onArchived={handleArchived}
@@ -159,6 +161,7 @@ function ConversationCardLoading(props: { index: number }) {
 }
 
 function ConversationCardSection(props: {
+  finishedConversationIds: ReadonlySet<string>;
   onArchiveError(conversation: Conversation, wasArchiving: boolean): void;
   onArchived(conversation: Conversation): void;
   section: ConversationSection;
@@ -175,6 +178,9 @@ function ConversationCardSection(props: {
         {props.section.conversations.map((conversation) => (
           <ConversationCard
             conversation={conversation}
+            finishedSinceSeen={props.finishedConversationIds.has(
+              conversation.id,
+            )}
             key={conversation.id}
             onArchiveError={props.onArchiveError}
             onArchived={props.onArchived}
@@ -187,6 +193,7 @@ function ConversationCardSection(props: {
 
 function ConversationCard(props: {
   conversation: Conversation;
+  finishedSinceSeen: boolean;
   onArchiveError(conversation: Conversation, wasArchiving: boolean): void;
   onArchived(conversation: Conversation): void;
 }) {
@@ -216,24 +223,11 @@ function ConversationCard(props: {
       <div className="relative z-[1] grid min-w-0 grid-cols-[minmax(0,1fr)_max-content] items-start gap-3 pointer-events-none">
         <div className="flex min-w-0 items-start gap-2.5">
           <span className="mt-1.5 grid size-3 shrink-0 place-items-center">
-            {isPrivate ? (
-              <LockKeyhole
-                aria-label="Private conversation"
-                className="size-3 text-dashboard-text-muted"
-              />
-            ) : status === "active" ? (
-              <ActiveIndicator className="size-1.5" />
-            ) : (
-              <span
-                aria-hidden="true"
-                className={cn(
-                  "size-1.5 rounded-full",
-                  status === "failed"
-                    ? "bg-rose-300"
-                    : "bg-dashboard-text-muted/40",
-                )}
-              />
-            )}
+            <ConversationListStatusIcon
+              finishedSinceSeen={props.finishedSinceSeen}
+              isPrivate={isPrivate}
+              status={status}
+            />
           </span>
           <h4 className="m-0 truncate font-display text-base font-medium leading-snug text-dashboard-text">
             {title}
diff --git a/packages/junior-dashboard/src/client/conversations/ConversationListStatusIcon.tsx b/packages/junior-dashboard/src/client/conversations/ConversationListStatusIcon.tsx
new file mode 100644
index 0000000000..58ca64337c
--- /dev/null
+++ b/packages/junior-dashboard/src/client/conversations/ConversationListStatusIcon.tsx
@@ -0,0 +1,52 @@
+import { LockKeyhole } from "lucide-react";
+
+import { ActiveIndicator } from "../components/ActiveIndicator";
+import { cn } from "../styles";
+import type { VisualStatus } from "../types";
+
+/** Render a conversation status marker, with new completions taking priority. */
+export function ConversationListStatusIcon(props: {
+  finishedSinceSeen: boolean;
+  isPrivate: boolean;
+  status: VisualStatus;
+}) {
+  if (props.finishedSinceSeen) {
+    return (
+      <span
+        aria-label="Finished since last viewed"
+        className="size-1.5 shrink-0 rounded-full bg-orange-300"
+        role="img"
+      />
+    );
+  }
+
+  if (props.isPrivate) {
+    return (
+      <LockKeyhole
+        aria-label="Private conversation"
+        className={cn(
+          "size-3 shrink-0",
+          props.status === "active" &&
+            "animate-[junior-active-indicator_1.8s_ease-in-out_infinite] text-emerald-300 drop-shadow-[0_0_6px_rgba(110,231,183,0.55)] motion-reduce:animate-none",
+          props.status === "failed" && "text-rose-300",
+          props.status === "idle" && "text-dashboard-text-muted",
+        )}
+      />
+    );
+  }
+
+  if (props.status === "active") {
+    return <ActiveIndicator className="size-1.5" />;
+  }
+
+  return (
+    <span
+      aria-hidden="true"
+      className={cn(
+        "size-1.5 shrink-0 rounded-full",
+        props.status === "failed" && "bg-rose-300",
+        props.status === "idle" && "bg-white/25",
+      )}
+    />
+  );
+}
diff --git a/packages/junior-dashboard/src/client/conversations/ConversationPage.tsx b/packages/junior-dashboard/src/client/conversations/ConversationPage.tsx
index 1419709b72..e44cc4c16c 100644
--- a/packages/junior-dashboard/src/client/conversations/ConversationPage.tsx
+++ b/packages/junior-dashboard/src/client/conversations/ConversationPage.tsx
@@ -66,6 +66,7 @@ export { liveModelId } from "./ConversationMeta";
 export function ConversationPage(props: {
   conversationId: string;
   data?: { conversations: ConversationFeed };
+  onRead?(conversationId: string, lastReadAt: string): void;
   pendingArchiveUpdate?: PendingArchiveConversationUpdate;
 }) {
   const [subagentTarget, setSubagentTarget] =
@@ -74,6 +75,7 @@ export function ConversationPage(props: {
   const [search, setSearch] = useState("");
   const [pinRequestVersion, setPinRequestVersion] = useState(0);
   const conversationId = props.conversationId;
+  const onRead = props.onRead;
   const summaries = props.data?.conversations.conversations ?? [];
   const conversations = buildConversations(summaries);
   const detail = useConversationData(conversationId);
@@ -86,6 +88,10 @@ export function ConversationPage(props: {
     props.pendingArchiveUpdate,
   );
   const conversationDetail = detail.data;
+  useEffect(() => {
+    if (!conversation) return;
+    onRead?.(conversation.id, conversation.lastSeenAt);
+  }, [conversation, onRead]);
   // Live polls can rebuild a large transcript tree every 2s. Defer that paint so
   // composer keystrokes stay urgent without changing visible transcript content.
   // Fall back to the latest detail on first load so the body is never blank while
diff --git a/packages/junior-dashboard/src/client/conversations/ConversationSidebar.tsx b/packages/junior-dashboard/src/client/conversations/ConversationSidebar.tsx
index 388b7fd490..866f4910d9 100644
--- a/packages/junior-dashboard/src/client/conversations/ConversationSidebar.tsx
+++ b/packages/junior-dashboard/src/client/conversations/ConversationSidebar.tsx
@@ -1,11 +1,5 @@
 import { memo, useCallback, useEffect, useMemo, useState } from "react";
-import {
-  Archive,
-  ArchiveRestore,
-  CircleAlert,
-  LockKeyhole,
-  SquarePen,
-} from "lucide-react";
+import { Archive, ArchiveRestore, CircleAlert, SquarePen } from "lucide-react";
 import { Link } from "react-router";
 
 import { useArchiveConversation } from "./queries";
@@ -16,8 +10,7 @@ import {
   visualStatusForConversation,
 } from "../format";
 import { cn } from "../styles";
-import type { Conversation, VisualStatus } from "../types";
-import { ActiveIndicator } from "../components/ActiveIndicator";
+import type { Conversation } from "../types";
 import { Notice, NoticeAction } from "../components/Notice";
 import { AnimatedList } from "./AnimatedList";
 import {
@@ -28,6 +21,7 @@ import { EmptyTelemetry } from "../components/EmptyTelemetry";
 import { SearchInput } from "../components/SearchInput";
 import { Skeleton } from "../components/Skeleton";
 import { ConversationSidebarAnnotations } from "./ConversationMeta";
+import { ConversationListStatusIcon } from "./ConversationListStatusIcon";
 
 type ConversationSidebarEntry =
   | { first: boolean; key: string; kind: "section"; label: string }
@@ -43,6 +37,7 @@ const conversationEntryKey = (entry: ConversationSidebarEntry) => entry.key;
 export function ConversationSidebar(props: {
   conversations: Conversation[];
   error?: string;
+  finishedConversationIds: ReadonlySet<string>;
   loading: boolean;
   query: string;
   selectedId?: string;
@@ -173,6 +168,9 @@ export function ConversationSidebar(props: {
               ) : (
                 <ConversationSidebarRow
                   conversation={entry.conversation}
+                  finishedSinceSeen={props.finishedConversationIds.has(
+                    entry.conversation.id,
+                  )}
                   onArchiveError={handleArchiveError}
                   onArchived={handleArchived}
                   selected={entry.conversation.id === props.selectedId}
@@ -255,44 +253,9 @@ function conversationSidebarEntries(
   ]);
 }
 
-/** Status glyph for a sidebar row; private rows use the lock instead of a dot. */
-function ConversationListStatusIcon(props: {
-  isPrivate: boolean;
-  status: VisualStatus;
-}) {
-  if (props.isPrivate) {
-    return (
-      <LockKeyhole
-        aria-label="Private conversation"
-        className={cn(
-          "size-3 shrink-0",
-          props.status === "active" &&
-            "animate-[junior-active-indicator_1.8s_ease-in-out_infinite] text-emerald-300 drop-shadow-[0_0_6px_rgba(110,231,183,0.55)] motion-reduce:animate-none",
-          props.status === "failed" && "text-rose-300",
-          props.status === "idle" && "text-dashboard-text-muted",
-        )}
-      />
-    );
-  }
-
-  if (props.status === "active") {
-    return <ActiveIndicator className="size-1.5" />;
-  }
-
-  return (
-    <span
-      aria-hidden="true"
-      className={cn(
-        "size-1.5 shrink-0 rounded-full",
-        props.status === "failed" && "bg-rose-300",
-        props.status === "idle" && "bg-white/25",
-      )}
-    />
-  );
-}
-
 const ConversationSidebarRow = memo(function ConversationSidebarRow(props: {
   conversation: Conversation;
+  finishedSinceSeen: boolean;
   onArchiveError(conversation: Conversation, wasArchiving: boolean): void;
   onArchived(conversation: Conversation): void;
   selected: boolean;
@@ -337,7 +300,11 @@ const ConversationSidebarRow = memo(function ConversationSidebarRow(props: {
       >
         <div className="grid min-w-0 grid-cols-[auto_minmax(0,1fr)] items-start gap-x-1.5">
           <div className="col-start-1 row-start-1 mt-[0.3rem] grid size-3 shrink-0 place-items-center">
-            <ConversationListStatusIcon isPrivate={isPrivate} status={status} />
+            <ConversationListStatusIcon
+              finishedSinceSeen={props.finishedSinceSeen}
+              isPrivate={isPrivate}
+              status={status}
+            />
           </div>
           <div className="col-start-2 row-start-1 min-w-0 truncate font-display text-sm font-medium leading-snug text-dashboard-text">
             {title}
diff --git a/packages/junior-dashboard/src/client/conversations/ConversationWorkspace.tsx b/packages/junior-dashboard/src/client/conversations/ConversationWorkspace.tsx
index 15dd3fc6a3..b0fef6202a 100644
--- a/packages/junior-dashboard/src/client/conversations/ConversationWorkspace.tsx
+++ b/packages/junior-dashboard/src/client/conversations/ConversationWorkspace.tsx
@@ -19,6 +19,7 @@ import { buildConversations, getDashboardTimeZone } from "../format";
 import type { Conversation } from "../types";
 import { cn, dashboardContainerClass } from "../styles";
 import { ConversationPage } from "./ConversationPage";
+import { useConversationFinishedIndicators } from "./useConversationFinishedIndicators";
 
 const CONVERSATION_PAGE_SIZE = 20;
 
@@ -59,6 +60,13 @@ export function ConversationWorkspace() {
   useEffect(() => {
     if (page > totalPages) setPage(totalPages);
   }, [page, totalPages]);
+  const { finishedConversationIds, markRead } =
+    useConversationFinishedIndicators(
+      conversations,
+      selectedId,
+      Boolean(feed.data),
+      !search,
+    );
 
   const createView = (
     <NewConversationView
@@ -99,6 +107,7 @@ export function ConversationWorkspace() {
             <ConversationHomeList
               conversations={pagedConversations}
               emptyLabel={feed.error?.message}
+              finishedConversationIds={finishedConversationIds}
               loading={feed.isPending}
               timeZone={getDashboardTimeZone()}
             />
@@ -127,6 +136,7 @@ export function ConversationWorkspace() {
         <ConversationSidebar
           conversations={conversations}
           error={feed.error?.message}
+          finishedConversationIds={finishedConversationIds}
           loading={feed.isPending}
           onNewConversation={openCreate}
           onQueryChange={setQuery}
@@ -149,6 +159,7 @@ export function ConversationWorkspace() {
                 }
               : undefined
           }
+          onRead={markRead}
           pendingArchiveUpdate={pendingArchiveUpdates.find(
             (update) => update.conversationId === selectedId,
           )}
diff --git a/packages/junior-dashboard/src/client/conversations/useConversationFinishedIndicators.ts b/packages/junior-dashboard/src/client/conversations/useConversationFinishedIndicators.ts
new file mode 100644
index 0000000000..1fd8f8fd9c
--- /dev/null
+++ b/packages/junior-dashboard/src/client/conversations/useConversationFinishedIndicators.ts
@@ -0,0 +1,151 @@
+import { useCallback, useEffect, useMemo, useState } from "react";
+
+import type { Conversation } from "../types";
+
+const STORAGE_KEY = "junior:conversation-finished-indicators";
+
+type StoredConversationState = {
+  lastReadAt: string;
+};
+
+type StoredConversationStates = Record<string, StoredConversationState>;
+
+type ConversationFinishedIndicators = {
+  finishedConversationIds: ReadonlySet<string>;
+  markRead(conversationId: string, lastReadAt: string): void;
+};
+
+/** Track visible idle conversations that have activity after the user read them. */
+export function useConversationFinishedIndicators(
+  conversations: Conversation[],
+  selectedId: string | undefined,
+  ready: boolean,
+  pruneMissing: boolean,
+): ConversationFinishedIndicators {
+  const [storedStates, setStoredStates] = useState(readStoredStates);
+
+  useEffect(() => {
+    if (!ready) return;
+
+    setStoredStates((current) => {
+      const next = reconcileStoredStates(
+        current,
+        conversations,
+        selectedId,
+        pruneMissing,
+      );
+      writeStoredStates(next);
+      return next;
+    });
+  }, [conversations, pruneMissing, ready, selectedId]);
+
+  const markRead = useCallback((conversationId: string, lastReadAt: string) => {
+    setStoredStates((current) => {
+      const previous = current[conversationId];
+      if (previous && !isAfter(lastReadAt, previous.lastReadAt)) return current;
+
+      const next = { ...current, [conversationId]: { lastReadAt } };
+      writeStoredStates(next);
+      return next;
+    });
+  }, []);
+
+  return {
+    finishedConversationIds: useMemo(
+      () => finishedConversationIds(storedStates, conversations, selectedId),
+      [conversations, selectedId, storedStates],
+    ),
+    markRead,
+  };
+}
+
+/** Find idle conversations with activity after the user read them. */
+export function finishedConversationIds(
+  states: StoredConversationStates,
+  conversations: Conversation[],
+  selectedId: string | undefined,
+): ReadonlySet<string> {
+  return new Set(
+    conversations
+      .filter((conversation) => {
+        const state = states[conversation.id];
+        return (
+          conversation.id !== selectedId &&
+          conversation.status === "completed" &&
+          state !== undefined &&
+          isAfter(conversation.lastSeenAt, state.lastReadAt)
+        );
+      })
+      .map((conversation) => conversation.id),
+  );
+}
+
+/** Record reads and remove conversations outside the visible list. */
+export function reconcileStoredStates(
+  current: StoredConversationStates,
+  conversations: Conversation[],
+  selectedId: string | undefined,
+  pruneMissing = true,
+): StoredConversationStates {
+  const visibleStates = Object.fromEntries(
+    conversations.map((conversation) => {
+      const previous = current[conversation.id];
+      const lastReadAt =
+        conversation.id === selectedId || previous === undefined
+          ? conversation.lastSeenAt
+          : previous.lastReadAt;
+
+      return [conversation.id, { lastReadAt }];
+    }),
+  );
+  if (pruneMissing) return visibleStates;
+  return { ...current, ...visibleStates };
+}
+
+function isAfter(value: string, reference: string): boolean {
+  const valueTime = Date.parse(value);
+  const referenceTime = Date.parse(reference);
+  return (
+    Number.isFinite(valueTime) &&
+    Number.isFinite(referenceTime) &&
+    valueTime > referenceTime
+  );
+}
+
+function readStoredStates(): StoredConversationStates {
+  if (typeof window === "undefined") return {};
+
+  try {
+    const value: unknown = JSON.parse(
+      window.localStorage.getItem(STORAGE_KEY) ?? "{}",
+    );
+    if (!value || typeof value !== "object" || Array.isArray(value)) return {};
+
+    return Object.fromEntries(
+      Object.entries(value).filter(
+        (entry): entry is [string, StoredConversationState] => {
+          const state: unknown = entry[1];
+          return (
+            state !== null &&
+            typeof state === "object" &&
+            "lastReadAt" in state &&
+            typeof state.lastReadAt === "string" &&
+            Number.isFinite(Date.parse(state.lastReadAt))
+          );
+        },
+      ),
+    );
+  } catch {
+    return {};
+  }
+}
+
+function writeStoredStates(states: StoredConversationStates): void {
+  if (typeof window === "undefined") return;
+
+  try {
+    window.localStorage.setItem(STORAGE_KEY, JSON.stringify(states));
+  } catch {
+    // Keep in-memory indicators usable when storage is unavailable.
+  }
+}
diff --git a/packages/junior-dashboard/tests/conversation-finished-indicators.test.ts b/packages/junior-dashboard/tests/conversation-finished-indicators.test.ts
new file mode 100644
index 0000000000..87dd23f314
--- /dev/null
+++ b/packages/junior-dashboard/tests/conversation-finished-indicators.test.ts
@@ -0,0 +1,68 @@
+import { describe, expect, it } from "vitest";
+
+import {
+  finishedConversationIds,
+  reconcileStoredStates,
+} from "../src/client/conversations/useConversationFinishedIndicators";
+import type { Conversation } from "../src/client/types";
+
+function conversation(
+  id: string,
+  status: Conversation["status"],
+  lastSeenAt = "2026-09-11T00:00:00.000Z",
+): Conversation {
+  return {
+    cumulativeDurationMs: 0,
+    displayTitle: id,
+    id,
+    lastProgressAt: lastSeenAt,
+    lastSeenAt,
+    startedAt: "2026-09-11T00:00:00.000Z",
+    status,
+    surface: "api",
+  };
+}
+
+describe("conversation finished indicators", () => {
+  it("marks an idle conversation when it has activity after the last read", () => {
+    const states = reconcileStoredStates(
+      {},
+      [conversation("a", "active")],
+      undefined,
+    );
+    const updated = conversation("a", "completed", "2026-09-11T00:01:00.000Z");
+
+    expect([...finishedConversationIds(states, [updated], undefined)]).toEqual([
+      "a",
+    ]);
+  });
+
+  it("records a selected conversation as read and removes hidden conversations", () => {
+    const current = {
+      a: { lastReadAt: "2026-09-11T00:00:00.000Z" },
+      hidden: { lastReadAt: "2026-09-11T00:00:00.000Z" },
+    };
+    const updated = conversation("a", "completed", "2026-09-11T00:01:00.000Z");
+
+    expect(reconcileStoredStates(current, [updated], "a")).toEqual({
+      a: { lastReadAt: "2026-09-11T00:01:00.000Z" },
+    });
+    expect([...finishedConversationIds(current, [updated], "a")]).toEqual([]);
+  });
+
+  it("keeps conversations outside filtered results", () => {
+    const current = {
+      a: { lastReadAt: "2026-09-11T00:00:00.000Z" },
+      hidden: { lastReadAt: "2026-09-11T00:00:00.000Z" },
+    };
+
+    expect(
+      reconcileStoredStates(
+        current,
+        [conversation("a", "completed")],
+        undefined,
+        false,
+      ),
+    ).toEqual(current);
+  });
+});