fix(core): restore archived cloud task logs

Generated-By: PostHog Code
Task-Id: c1bbe3cf-742b-4b24-bf96-d11a18b4cf22

Author: richardsolomou

packages/core/src/cloud-task/cloud-task-engine.ts

@@ -81,6 +81,7 @@ class BackendStreamError extends Error {
 
 interface TaskRunResponse {
   id: string;
+  log_url?: string | null;
   status: TaskRunStatus;
   stage?: string | null;
   output?: Record<string, unknown> | null;
@@ -1106,7 +1107,10 @@ export class CloudTaskEngine extends TypedEventEmitter<CloudTaskEvents> {
     }
 
     if (isTerminalStatus(run.status)) {
-      const historicalEntries = await this.fetchAllSessionLogs(watcher);
+      let historicalEntries = await this.fetchAllSessionLogs(watcher);
+      if (historicalEntries?.length === 0 && run.log_url) {
+        historicalEntries = await this.fetchArchivedLogs(run.log_url);
+      }
       const terminalWatcher = this.watchers.get(key);
       if (!terminalWatcher || terminalWatcher !== watcher) return;
       if (watcher.failed) return;
@@ -2154,6 +2158,24 @@ export class CloudTaskEngine extends TypedEventEmitter<CloudTaskEvents> {
     }
   }
 
+  private async fetchArchivedLogs(
+    logUrl: string,
+  ): Promise<StoredLogEntry[] | null> {
+    try {
+      const response = await this.streamFetch(logUrl);
+      if (!response.ok) return null;
+      const content = await response.text();
+      if (!content.trim()) return [];
+      return content
+        .trim()
+        .split("\n")
+        .map((line) => JSON.parse(line) as StoredLogEntry);
+    } catch (error) {
+      this.log.warn("Cloud task archived logs fetch error", { logUrl, error });
+      return null;
+    }
+  }
+
   private async resolveStreamTarget(watcher: WatcherState): Promise<void> {
     const url = `${watcher.apiHost}/api/projects/${watcher.teamId}/tasks/${watcher.taskId}/runs/${watcher.runId}/stream_token/`;
     try {

packages/core/src/cloud-task/cloud-task.test.ts

@@ -2532,6 +2532,54 @@ describe("CloudTaskEngine", () => {
     expect(statusFetchCount).toBeLessThanOrEqual(2);
   });
 
+  it("loads archived logs when a terminal run has no persisted session logs", async () => {
+    const updates: unknown[] = [];
+    service.on(CloudTaskEvent.Update, (payload) => updates.push(payload));
+    const archivedEntry = {
+      type: "notification",
+      timestamp: "2026-01-01T00:00:00Z",
+    };
+
+    mockNetFetch.mockImplementation((input: string | Request) => {
+      const url = typeof input === "string" ? input : input.url;
+      if (url.includes("/session_logs/")) {
+        return Promise.resolve(
+          createJsonResponse([], 200, { "X-Has-More": "false" }),
+        );
+      }
+      if (url === "https://logs.example.com/run-1.jsonl") {
+        return Promise.resolve(
+          new Response(`${JSON.stringify(archivedEntry)}\n`, { status: 200 }),
+        );
+      }
+      return Promise.resolve(
+        createJsonResponse({
+          id: "run-1",
+          status: "completed",
+          log_url: "https://logs.example.com/run-1.jsonl",
+          updated_at: "2026-01-01T00:00:00Z",
+        }),
+      );
+    });
+
+    service.watch({
+      taskId: "task-1",
+      runId: "run-1",
+      apiHost: "https://app.example.com",
+      teamId: 2,
+    });
+
+    await waitFor(() => updates.length === 1);
+    expect(updates[0]).toEqual(
+      expect.objectContaining({
+        kind: "snapshot",
+        newEntries: [archivedEntry],
+        totalEntryCount: 1,
+        status: "completed",
+      }),
+    );
+  });
+
   const guardedFetchStatusExpectations = [
     [
       401,