diff --git a/src/features/threads/utils/threadSummary.test.ts b/src/features/threads/utils/threadSummary.test.ts
new file mode 100644
index 0000000000..cf0570574a
--- /dev/null
+++ b/src/features/threads/utils/threadSummary.test.ts
@@ -0,0 +1,52 @@
+import { describe, expect, it } from "vitest";
+import { buildThreadSummaryFromThread } from "./threadSummary";
+
+const baseThread = {
+  id: "thread-1",
+  name: "Server-provided name",
+  preview: "First message preview",
+  source: "vscode",
+};
+
+describe("buildThreadSummaryFromThread", () => {
+  it("prefers the server-provided thread name over the message preview", () => {
+    const summary = buildThreadSummaryFromThread({
+      workspaceId: "workspace-1",
+      thread: baseThread,
+      fallbackIndex: 0,
+    });
+
+    expect(summary?.name).toBe("Server-provided name");
+  });
+
+  it("keeps an explicit local rename ahead of the server-provided name", () => {
+    const summary = buildThreadSummaryFromThread({
+      workspaceId: "workspace-1",
+      thread: baseThread,
+      fallbackIndex: 0,
+      getCustomName: () => "Local rename",
+    });
+
+    expect(summary?.name).toBe("Local rename");
+  });
+
+  it("falls back to the message preview when the server has no name", () => {
+    const summary = buildThreadSummaryFromThread({
+      workspaceId: "workspace-1",
+      thread: { ...baseThread, name: null },
+      fallbackIndex: 0,
+    });
+
+    expect(summary?.name).toBe("First message preview");
+  });
+
+  it("supports title as a compatibility fallback", () => {
+    const summary = buildThreadSummaryFromThread({
+      workspaceId: "workspace-1",
+      thread: { ...baseThread, name: null, title: "Legacy title" },
+      fallbackIndex: 0,
+    });
+
+    expect(summary?.name).toBe("Legacy title");
+  });
+});
diff --git a/src/features/threads/utils/threadSummary.ts b/src/features/threads/utils/threadSummary.ts
index a23a6c76ae..f9d30d932b 100644
--- a/src/features/threads/utils/threadSummary.ts
+++ b/src/features/threads/utils/threadSummary.ts
@@ -49,9 +49,10 @@ export function buildThreadSummaryFromThread({
   const preview = asString(thread.preview ?? "").trim();
   const customName = getCustomName?.(workspaceId, id);
   const fallbackName = `Agent ${fallbackIndex + 1}`;
+  const serverName = asString(thread.name ?? thread.title ?? "").trim();
   const name = customName
     ? customName
-    : clampThreadName(preview) ?? fallbackName;
+    : clampThreadName(serverName || preview) ?? fallbackName;
   const metadata = extractThreadCodexMetadata(thread);
   if (shouldHideSubagentThreadFromSidebar(thread.source)) {
     return null;