fix(FN-1952): bound recovery and task log growth

packages/dashboard/src/routes.test.ts

@@ -487,6 +487,26 @@ describe("GET /tasks/:id", () => {
     expect(res.body.prompt).toBe("# KB-001\n\nTest task");
   });
 
+  it("caps task detail activity logs to keep the modal payload bounded", async () => {
+    const log = Array.from({ length: 510 }, (_, index) => ({
+      timestamp: `2026-01-01T00:${String(index % 60).padStart(2, "0")}:00.000Z`,
+      action: `entry-${index}`,
+    }));
+    (store.getTask as ReturnType<typeof vi.fn>).mockResolvedValue({
+      ...FAKE_TASK_DETAIL,
+      log,
+    });
+
+    const res = await GET(buildApp(), "/api/tasks/KB-001");
+
+    expect(res.status).toBe(200);
+    expect(res.body.log).toHaveLength(500);
+    expect(res.body.log[0].action).toBe("entry-10");
+    expect(res.body.log[499].action).toBe("entry-509");
+    expect(res.body.activityLogTotal).toBe(510);
+    expect(res.body.activityLogTruncatedCount).toBe(10);
+  });
+
   it("returns 404 when task genuinely does not exist (ENOENT)", async () => {
     const err: NodeJS.ErrnoException = new Error("ENOENT: no such file or directory");
     err.code = "ENOENT";

packages/dashboard/src/routes.ts

@@ -64,6 +64,8 @@ import {
 import { rateLimit, RATE_LIMITS } from "./rate-limit.js";
 import { resolvePluginManifest } from "./plugin-routes.js";
 
+const TASK_DETAIL_ACTIVITY_LOG_LIMIT = 500;
+
 /**
  * Minimal interface matching pi-coding-agent's ModelRegistry API surface
  * used by the models route. Avoids a direct dependency on the pi-coding-agent package.
@@ -642,6 +644,19 @@ function logEntryToTimelineEntry(entry: import("@fusion/core").AgentLogEntry): T
   };
 }
 
+function trimTaskDetailActivityLog<T extends Task>(task: T): T {
+  if (!Array.isArray(task.log) || task.log.length <= TASK_DETAIL_ACTIVITY_LOG_LIMIT) {
+    return task;
+  }
+
+  return {
+    ...task,
+    log: task.log.slice(-TASK_DETAIL_ACTIVITY_LOG_LIMIT),
+    activityLogTotal: task.log.length,
+    activityLogTruncatedCount: task.log.length - TASK_DETAIL_ACTIVITY_LOG_LIMIT,
+  } as T;
+}
+
 // ── Git Remote Detection ──────────────────────────────────────────
 
 /** Git remote info returned by the remotes endpoint */
@@ -3784,8 +3799,10 @@ export function createApiRoutes(store: TaskStore, options?: ServerOptions): Rout
   router.get("/tasks/:id", async (req, res) => {
     try {
       const { store: scopedStore } = await getProjectContext(req);
-      const task = await scopedStore.getTask(req.params.id);
-      res.json(task);
+      const task = await scopedStore.getTask(req.params.id, {
+        activityLogLimit: TASK_DETAIL_ACTIVITY_LOG_LIMIT,
+      });
+      res.json(trimTaskDetailActivityLog(task));
     } catch (err: unknown) {
       if (err instanceof ApiError) {
         throw err;