diff --git a/desktop/src/features/sidebar/ui/WorkspaceRail.test.mjs b/desktop/src/features/sidebar/ui/WorkspaceRail.test.mjs
index 8f33ca1cb..358af9c53 100644
--- a/desktop/src/features/sidebar/ui/WorkspaceRail.test.mjs
+++ b/desktop/src/features/sidebar/ui/WorkspaceRail.test.mjs
@@ -25,22 +25,25 @@ describe("workspaceRailIndicators", () => {
   it("shows no badge for an observed workspace with unread but no mentions", () => {
     const r = workspaceRailIndicators({ hasUnread: true, state: "ready" });
     assert.equal(r.showBadge, false);
+    assert.equal(r.showDot, true);
     assert.equal(r.pending, false);
   });
 
-  it("shows no badge for an observed workspace with no unread", () => {
+  it("shows no badge and no dot for an observed workspace with no unread", () => {
     const r = workspaceRailIndicators({ hasUnread: false, state: "ready" });
     assert.equal(r.showBadge, false);
+    assert.equal(r.showDot, false);
     assert.equal(r.pending, false);
   });
 
-  it("shows a mention badge with the count when mentions are present", () => {
+  it("shows a mention badge with the count when mentions are present — no dot", () => {
     const r = workspaceRailIndicators({
       hasUnread: true,
       count: 3,
       state: "ready",
     });
     assert.equal(r.showBadge, true);
+    assert.equal(r.showDot, false);
     assert.equal(r.mentionCount, 3);
     assert.equal(r.badgeLabel, "3");
   });
@@ -54,30 +57,33 @@ describe("workspaceRailIndicators", () => {
     assert.equal(r.badgeLabel, "99+");
   });
 
-  it("never reports mentions for an unobserved (unknown) workspace", () => {
+  it("never reports mentions or dot for an unobserved (unknown) workspace", () => {
     const r = workspaceRailIndicators({
       hasUnread: true,
       count: 5,
       state: "unknown",
     });
     assert.equal(r.showBadge, false);
+    assert.equal(r.showDot, false);
     assert.equal(r.mentionCount, 0);
     assert.equal(r.pending, true);
   });
 
-  it("treats loading as pending, not as no-unread", () => {
+  it("treats loading as pending — no badge, no dot", () => {
     const r = workspaceRailIndicators({ hasUnread: false, state: "loading" });
     assert.equal(r.pending, true);
     assert.equal(r.showBadge, false);
+    assert.equal(r.showDot, false);
   });
 
-  it("never reports mentions on an errored observation", () => {
+  it("never reports mentions or dot on an errored observation", () => {
     const r = workspaceRailIndicators({
       hasUnread: true,
       count: 2,
       state: "error",
     });
     assert.equal(r.showBadge, false);
+    assert.equal(r.showDot, false);
     assert.equal(r.mentionCount, 0);
     assert.equal(r.pending, false);
   });
diff --git a/desktop/src/features/sidebar/ui/WorkspaceRail.tsx b/desktop/src/features/sidebar/ui/WorkspaceRail.tsx
index 12984f95e..2d6b98cbd 100644
--- a/desktop/src/features/sidebar/ui/WorkspaceRail.tsx
+++ b/desktop/src/features/sidebar/ui/WorkspaceRail.tsx
@@ -45,21 +45,29 @@ export function workspaceInitials(name: string): string {
 /**
  * Presentation decisions for one workspace button, derived from its observed
  * mention state. Pure so it can be unit-tested without a DOM. The `state` guard
- * ensures we NEVER render a mention badge for a relay we could not observe
+ * ensures we NEVER render any indicator for a relay we could not observe
  * (`unknown`/`loading`/`error`) — only a `ready` observation is trusted.
+ *
+ * Two-tier indicator system:
+ * - `showBadge`: numeric mention count (mentions/thread-replies present).
+ * - `showDot`: plain unread dot when there are regular channel unreads but no
+ *   mentions. Mutually exclusive with `showBadge` by construction.
  */
 export function workspaceRailIndicators(unread: WorkspaceUnreadState): {
   mentionCount: number;
   showBadge: boolean;
+  showDot: boolean;
   pending: boolean;
   badgeLabel: string;
 } {
   const observed = unread.state === "ready";
   const mentionCount = observed ? (unread.count ?? 0) : 0;
   const showBadge = mentionCount > 0;
+  const showDot = observed && unread.hasUnread && !showBadge;
   return {
     mentionCount,
     showBadge,
+    showDot,
     pending: unread.state === "unknown" || unread.state === "loading",
     badgeLabel:
       mentionCount > MAX_BADGE ? `${MAX_BADGE}+` : String(mentionCount),
@@ -81,12 +89,14 @@ function WorkspaceButton({
   onSwitch: () => void;
   menu: React.ReactNode;
 }) {
-  const { mentionCount, showBadge, pending, badgeLabel } =
+  const { mentionCount, showBadge, showDot, pending, badgeLabel } =
     workspaceRailIndicators(unread);
 
   const tooltipLabel = showBadge
     ? `${workspace.name} — ${mentionCount} mention${mentionCount === 1 ? "" : "s"}`
-    : workspace.name;
+    : showDot
+      ? `${workspace.name} — unread`
+      : workspace.name;
 
   return (
     <ContextMenu>
@@ -129,6 +139,13 @@ function WorkspaceButton({
                 >
                   {badgeLabel}
                 </span>
+              ) : showDot ? (
+                <span
+                  className="absolute -bottom-0.5 -right-0.5 h-2 w-2 shrink-0 rounded-full bg-primary ring-2 ring-sidebar"
+                  data-testid={`workspace-rail-unread-dot-${workspace.id}`}
+                >
+                  <span className="sr-only">unread</span>
+                </span>
               ) : null}
             </button>
           </ContextMenuTrigger>