fix(background): replay persisted updates before launch order

index.ts

@@ -110,7 +110,9 @@ export default function subagentsExtension(pi: ExtensionAPI, deps: any = {}) {
         }, { triggerTurn: false });
       } catch (e) {}
     } catch (e) {
-      // monitorRun errors are non-fatal here
+      // Monitoring runs happens in the background. Failures here should not
+      // block tool registration or the foreground session; monitorRun errors
+      // are best-effort and final failures are logged via result.json.
     }
   }
 
@@ -178,18 +180,25 @@ export default function subagentsExtension(pi: ExtensionAPI, deps: any = {}) {
     // replay persisted runs if session manager provides entries
     try {
       const entries = ctx.sessionManager?.getEntries?.() ?? [];
-      // clear existing registry and rebuild from session entries
+      const launches: any[] = [];
-      registry.replay([]);
+      const updates: any[] = [];
+
       for (const e of entries) {
         const type = (e.type ?? e.customType) as string | undefined;
         if (type === "pi-subagents:bg-run") {
           const run = e.data?.run ?? e.data;
-          if (run && run.runId) registry.recordLaunch(run as any);
+          if (run && run.runId) launches.push(run);
         } else if (type === "pi-subagents:bg-update") {
           const data = e.data;
-          if (data && data.runId) registry.recordUpdate(data.runId, data as any);
+          if (data && data.runId) updates.push(data);
         }
       }
+
+      // Rebuild in two passes so out-of-order persisted entries cannot drop
+      // terminal updates that happen to appear before their launch entry.
+      registry.replay([]);
+      for (const run of launches) registry.recordLaunch(run as any);
+      for (const update of updates) registry.recordUpdate(update.runId, update as any);
     } catch (e) {}
 
     updateStatus();

src/extension.test.ts

@@ -535,3 +535,73 @@ test("background completion updates footer status, appends session updates, noti
     else process.env.PI_SUBAGENTS_CHILD = original;
   }
 });
+
+test("session_start replay applies bg-update entries even when they appear before bg-run", async () => {
+  const original = process.env.PI_SUBAGENTS_CHILD;
+  if (original !== undefined) delete process.env.PI_SUBAGENTS_CHILD;
+
+  try {
+    const handlers: any = {};
+    const registeredTools: any[] = [];
+
+    subagentsExtension({
+      on(event: string, handler: (event: any, ctx: any) => Promise<void> | void) {
+        handlers[event] = handler;
+      },
+      registerTool(tool: any) {
+        registeredTools.push(tool);
+      },
+      registerProvider() {},
+      appendEntry() {},
+      sendMessage() {},
+    } as any);
+
+    await handlers.session_start?.(
+      { reason: "startup" },
+      {
+        modelRegistry: {
+          getAvailable: () => [{ provider: "openai", id: "gpt-5" }],
+        },
+        ui: {
+          notify() {},
+          setStatus() {},
+        },
+        sessionManager: {
+          getEntries: () => [
+            {
+              type: "pi-subagents:bg-update",
+              data: { runId: "run-1", status: "completed", exitCode: 0, finalText: "done" },
+            },
+            {
+              type: "pi-subagents:bg-run",
+              data: {
+                run: {
+                  runId: "run-1",
+                  preset: "repo-scout",
+                  task: "inspect auth",
+                  status: "running",
+                  startTime: Date.now(),
+                  paths: {
+                    eventsPath: "/tmp/run-1/events.jsonl",
+                    resultPath: "/tmp/run-1/result.json",
+                  },
+                },
+              },
+            },
+          ],
+        },
+      },
+    );
+
+    const statusTool = registeredTools.find((tool) => tool.name === "background_agent_status");
+    assert(statusTool, "background_agent_status registered");
+
+    const result: any = await statusTool.execute("tool-1", { runId: "run-1" }, undefined, undefined, undefined);
+    assert.equal(result.details.runs.length, 1);
+    assert.equal(result.details.runs[0].status, "completed");
+    assert.equal(result.details.counts.completed, 1);
+  } finally {
+    if (original === undefined) delete process.env.PI_SUBAGENTS_CHILD;
+    else process.env.PI_SUBAGENTS_CHILD = original;
+  }
+});