fix(server): avoid duplicating startup notices when timeline is already primed

packages/server/src/server/agent/agent-manager.test.ts

@@ -12687,6 +12687,19 @@ test("commits startup notices once on create and after restored history", async
     const created = await manager.createAgent({ provider: "codex", cwd: workdir }, undefined, {});
     ids.push(created.id);
     expect((await manager.getTimelineRows(created.id)).map((row) => row.item)).toEqual([notice]);
+    await manager.reloadAgentSession(created.id);
+    expect((await manager.getTimelineRows(created.id)).map((row) => row.item)).toEqual([notice]);
+    await manager.closeAgent(created.id);
+    await manager.resumeAgentFromPersistence(
+      {
+        provider: "codex",
+        sessionId: "existing-created",
+        metadata: { cwd: workdir },
+      },
+      undefined,
+      created.id,
+    );
+    expect((await manager.getTimelineRows(created.id)).map((row) => row.item)).toEqual([notice]);
     const resumed = await manager.resumeAgentFromPersistence({
       provider: "codex",
       sessionId: "existing",

packages/server/src/server/agent/agent-manager.ts

@@ -4029,9 +4029,11 @@ export class AgentManager {
           // Legacy/imported chats need their existing history before startup rows.
           await this.primeTimelineFromLegacyProviderHistory(managed, false, startupHistory);
         } else {
-          for (const entry of buildImportedTimelineRows(session.initialTimeline)) {
-            this.recordTimeline(managed.id, entry.item, { timestamp: entry.timestamp });
-          }
+          await this.recordInitialTimelineIfMissing(
+            managed,
+            session.initialTimeline,
+            durableTimelineHasRows,
+          );
         }
         this.refreshSessionPersistence(managed);
       }
@@ -4224,6 +4226,33 @@ export class AgentManager {
     };
   }
 
+  private async recordInitialTimelineIfMissing(
+    agent: ActiveManagedAgent,
+    initialTimeline: NonNullable<AgentSession["initialTimeline"]>,
+    durableTimelineHasRows: boolean,
+  ): Promise<void> {
+    const existingItems: AgentTimelineItem[] = [...this.timelineStore.getItems(agent.id)];
+    if (existingItems.length === 0 && durableTimelineHasRows && this.durableTimelineStore) {
+      for (const row of await this.durableTimelineStore.getCommittedRows(agent.id)) {
+        existingItems.push(row.item);
+      }
+    }
+    for (const entry of buildImportedTimelineRows(initialTimeline)) {
+      const alreadyRecorded = existingItems.some(
+        (item) =>
+          item.type === "notification" &&
+          entry.item.type === "notification" &&
+          item.level === entry.item.level &&
+          item.message === entry.item.message,
+      );
+      if (alreadyRecorded) {
+        continue;
+      }
+      this.recordTimeline(agent.id, entry.item, { timestamp: entry.timestamp });
+      existingItems.push(entry.item);
+    }
+  }
+
   private prepareAgentForClosure(
     agent: LiveManagedAgent,
     cancelReason: string,