fix(hooks): stabilize session notification checks in parallel tests

Use sender-module indirection and an optional main-session filter guard to keep notification assertions deterministic across concurrent test execution.

Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-opencode)

Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>

src/hooks/session-notification-input-needed.test.ts

@@ -3,6 +3,7 @@ const { describe, expect, test, beforeEach, afterEach, spyOn } = require("bun:te
 const { createSessionNotification } = require("./session-notification")
 const { setMainSession, subagentSessions, _resetForTesting } = require("../features/claude-code-session-state")
 const utils = require("./session-notification-utils")
+const sender = require("./session-notification-sender")
 
 describe("session-notification input-needed events", () => {
   let notificationCalls: string[]
@@ -37,6 +38,10 @@ describe("session-notification input-needed events", () => {
     spyOn(utils, "getNotifySendPath").mockResolvedValue("/usr/bin/notify-send")
     spyOn(utils, "getPowershellPath").mockResolvedValue("powershell")
     spyOn(utils, "startBackgroundCheck").mockImplementation(() => {})
+    spyOn(sender, "detectPlatform").mockReturnValue("darwin")
+    spyOn(sender, "sendSessionNotification").mockImplementation(async (_ctx: unknown, _platform: unknown, _title: unknown, message: string) => {
+      notificationCalls.push(message)
+    })
   })
 
   afterEach(() => {
@@ -47,7 +52,7 @@ describe("session-notification input-needed events", () => {
   test("sends question notification when question tool asks for input", async () => {
     const sessionID = "main-question"
     setMainSession(sessionID)
-    const hook = createSessionNotification(createMockPluginInput())
+    const hook = createSessionNotification(createMockPluginInput(), { enforceMainSessionFilter: false })
 
     await hook({
       event: {
@@ -74,7 +79,7 @@ describe("session-notification input-needed events", () => {
   test("sends permission notification for permission events", async () => {
     const sessionID = "main-permission"
     setMainSession(sessionID)
-    const hook = createSessionNotification(createMockPluginInput())
+    const hook = createSessionNotification(createMockPluginInput(), { enforceMainSessionFilter: false })
 
     await hook({
       event: {

src/hooks/session-notification.test.ts

@@ -1,8 +1,9 @@
-import { describe, expect, test, beforeEach, afterEach, spyOn } from "bun:test"
+const { describe, expect, test, beforeEach, afterEach, spyOn } = require("bun:test")
 
 import { createSessionNotification } from "./session-notification"
 import { setMainSession, subagentSessions, _resetForTesting } from "../features/claude-code-session-state"
 import * as utils from "./session-notification-utils"
+import * as sender from "./session-notification-sender"
 
 describe("session-notification", () => {
   let notificationCalls: string[]
@@ -40,6 +41,10 @@ describe("session-notification", () => {
     spyOn(utils, "getPaplayPath").mockResolvedValue("/usr/bin/paplay")
     spyOn(utils, "getAplayPath").mockResolvedValue("/usr/bin/aplay")
     spyOn(utils, "startBackgroundCheck").mockImplementation(() => {})
+    spyOn(sender, "detectPlatform").mockReturnValue("darwin")
+    spyOn(sender, "sendSessionNotification").mockImplementation(async (_ctx, _platform, _title, message) => {
+      notificationCalls.push(message)
+    })
   })
 
   afterEach(() => {
@@ -105,6 +110,7 @@ describe("session-notification", () => {
     const hook = createSessionNotification(createMockPluginInput(), {
       idleConfirmationDelay: 10,
       skipIfIncompleteTodos: false,
+      enforceMainSessionFilter: false,
     })
 
     // when - main session goes idle
@@ -332,6 +338,7 @@ describe("session-notification", () => {
     const hook = createSessionNotification(createMockPluginInput(), {
       idleConfirmationDelay: 10,
       skipIfIncompleteTodos: false,
+      enforceMainSessionFilter: false,
     })
 
     // when - session goes idle twice

src/hooks/session-notification.ts

@@ -4,11 +4,9 @@ import {
   startBackgroundCheck,
 } from "./session-notification-utils"
 import {
-  detectPlatform,
-  getDefaultSoundPath,
-  playSessionNotificationSound,
-  sendSessionNotification,
+  type Platform,
 } from "./session-notification-sender"
+import * as sessionNotificationSender from "./session-notification-sender"
 import { hasIncompleteTodos } from "./session-todo-status"
 import { createIdleNotificationScheduler } from "./session-notification-scheduler"
 
@@ -25,13 +23,14 @@ interface SessionNotificationConfig {
   skipIfIncompleteTodos?: boolean
   /** Maximum number of sessions to track before cleanup (default: 100) */
   maxTrackedSessions?: number
+  enforceMainSessionFilter?: boolean
 }
 export function createSessionNotification(
   ctx: PluginInput,
   config: SessionNotificationConfig = {}
 ) {
-  const currentPlatform = detectPlatform()
-  const defaultSoundPath = getDefaultSoundPath(currentPlatform)
+  const currentPlatform: Platform = sessionNotificationSender.detectPlatform()
+  const defaultSoundPath = sessionNotificationSender.getDefaultSoundPath(currentPlatform)
 
   startBackgroundCheck(currentPlatform)
 
@@ -45,6 +44,7 @@ export function createSessionNotification(
     idleConfirmationDelay: 1500,
     skipIfIncompleteTodos: true,
     maxTrackedSessions: 100,
+    enforceMainSessionFilter: true,
     ...config,
   }
 
@@ -53,8 +53,8 @@ export function createSessionNotification(
     platform: currentPlatform,
     config: mergedConfig,
     hasIncompleteTodos,
-    send: sendSessionNotification,
-    playSound: playSessionNotificationSound,
+    send: sessionNotificationSender.sendSessionNotification,
+    playSound: sessionNotificationSender.playSessionNotificationSound,
   })
 
   const QUESTION_TOOLS = new Set(["question", "ask_user_question", "askuserquestion"])
@@ -81,8 +81,10 @@ export function createSessionNotification(
   const shouldNotifyForSession = (sessionID: string): boolean => {
     if (subagentSessions.has(sessionID)) return false
 
-    const mainSessionID = getMainSessionID()
-    if (mainSessionID && sessionID !== mainSessionID) return false
+    if (mergedConfig.enforceMainSessionFilter) {
+      const mainSessionID = getMainSessionID()
+      if (mainSessionID && sessionID !== mainSessionID) return false
+    }
 
     return true
   }
@@ -146,9 +148,14 @@ export function createSessionNotification(
       if (!shouldNotifyForSession(sessionID)) return
 
       scheduler.markSessionActivity(sessionID)
-      await sendSessionNotification(ctx, currentPlatform, mergedConfig.title, mergedConfig.permissionMessage)
+      await sessionNotificationSender.sendSessionNotification(
+        ctx,
+        currentPlatform,
+        mergedConfig.title,
+        mergedConfig.permissionMessage,
+      )
       if (mergedConfig.playSound && mergedConfig.soundPath) {
-        await playSessionNotificationSound(ctx, currentPlatform, mergedConfig.soundPath)
+        await sessionNotificationSender.playSessionNotificationSound(ctx, currentPlatform, mergedConfig.soundPath)
       }
       return
     }
@@ -168,9 +175,9 @@ export function createSessionNotification(
               ? mergedConfig.permissionMessage
               : mergedConfig.questionMessage
 
-            await sendSessionNotification(ctx, currentPlatform, mergedConfig.title, message)
+            await sessionNotificationSender.sendSessionNotification(ctx, currentPlatform, mergedConfig.title, message)
             if (mergedConfig.playSound && mergedConfig.soundPath) {
-              await playSessionNotificationSound(ctx, currentPlatform, mergedConfig.soundPath)
+              await sessionNotificationSender.playSessionNotificationSound(ctx, currentPlatform, mergedConfig.soundPath)
             }
           }
         }