diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index fe8a0f11b..4696a7b74 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -67,6 +67,8 @@ jobs:
           bun test src/shared/opencode-message-dir.test.ts
           # session-recovery mock isolation (recover-tool-result-missing mocks ./storage)
           bun test src/hooks/session-recovery/recover-tool-result-missing.test.ts
+          # legacy-plugin-toast mock isolation (hook.test.ts mocks ./auto-migrate)
+          bun test src/hooks/legacy-plugin-toast/hook.test.ts
 
       - name: Run remaining tests
         run: |
@@ -98,6 +100,7 @@ jobs:
             src/tools/call-omo-agent/subagent-session-creator.test.ts \
             src/hooks/anthropic-context-window-limit-recovery/empty-content-recovery-sdk.test.ts src/hooks/anthropic-context-window-limit-recovery/parser.test.ts src/hooks/anthropic-context-window-limit-recovery/pruning-deduplication.test.ts src/hooks/anthropic-context-window-limit-recovery/recovery-deduplication.test.ts src/hooks/anthropic-context-window-limit-recovery/storage.test.ts \
             src/hooks/session-recovery/detect-error-type.test.ts src/hooks/session-recovery/index.test.ts src/hooks/session-recovery/recover-empty-content-message-sdk.test.ts src/hooks/session-recovery/resume.test.ts src/hooks/session-recovery/storage \
+            src/hooks/legacy-plugin-toast/auto-migrate.test.ts \
             src/hooks/claude-code-compatibility \
             src/hooks/context-injection \
             src/hooks/provider-toast \
diff --git a/.github/workflows/publish.yml b/.github/workflows/publish.yml
index 95a745ef0..1b3f78f4e 100644
--- a/.github/workflows/publish.yml
+++ b/.github/workflows/publish.yml
@@ -68,6 +68,8 @@ jobs:
           bun test src/shared/opencode-message-dir.test.ts
           # session-recovery mock isolation (recover-tool-result-missing mocks ./storage)
           bun test src/hooks/session-recovery/recover-tool-result-missing.test.ts
+          # legacy-plugin-toast mock isolation (hook.test.ts mocks ./auto-migrate)
+          bun test src/hooks/legacy-plugin-toast/hook.test.ts
 
       - name: Run remaining tests
         run: |
@@ -99,6 +101,7 @@ jobs:
             src/tools/call-omo-agent/subagent-session-creator.test.ts \
             src/hooks/anthropic-context-window-limit-recovery/empty-content-recovery-sdk.test.ts src/hooks/anthropic-context-window-limit-recovery/parser.test.ts src/hooks/anthropic-context-window-limit-recovery/pruning-deduplication.test.ts src/hooks/anthropic-context-window-limit-recovery/recovery-deduplication.test.ts src/hooks/anthropic-context-window-limit-recovery/storage.test.ts \
             src/hooks/session-recovery/detect-error-type.test.ts src/hooks/session-recovery/index.test.ts src/hooks/session-recovery/recover-empty-content-message-sdk.test.ts src/hooks/session-recovery/resume.test.ts src/hooks/session-recovery/storage \
+            src/hooks/legacy-plugin-toast/auto-migrate.test.ts \
             src/hooks/claude-code-compatibility \
             src/hooks/context-injection \
             src/hooks/provider-toast \
diff --git a/src/features/background-agent/background-task-notification-template.ts b/src/features/background-agent/background-task-notification-template.ts
index da17cda14..e2e74cc78 100644
--- a/src/features/background-agent/background-task-notification-template.ts
+++ b/src/features/background-agent/background-task-notification-template.ts
@@ -1,6 +1,6 @@
 import type { BackgroundTask } from "./types"
 
-export type BackgroundTaskNotificationStatus = "COMPLETED" | "CANCELLED" | "INTERRUPTED"
+export type BackgroundTaskNotificationStatus = "COMPLETED" | "CANCELLED" | "INTERRUPTED" | "ERROR"
 
 export function buildBackgroundTaskNotificationText(input: {
   task: BackgroundTask
@@ -15,21 +15,43 @@ export function buildBackgroundTaskNotificationText(input: {
   const errorInfo = task.error ? `\n**Error:** ${task.error}` : ""
 
   if (allComplete) {
-    const completedTasksText = completedTasks
-      .map((t) => `- \`${t.id}\`: ${t.description}`)
-      .join("\n")
+    const succeededTasks = completedTasks.filter((t) => t.status === "completed")
+    const failedTasks = completedTasks.filter((t) => t.status !== "completed")
+
+    const succeededText = succeededTasks.length > 0
+      ? succeededTasks.map((t) => `- \`${t.id}\`: ${t.description}`).join("\n")
+      : ""
+    const failedText = failedTasks.length > 0
+      ? failedTasks.map((t) => `- \`${t.id}\`: ${t.description} [${t.status.toUpperCase()}]${t.error ? ` - ${t.error}` : ""}`).join("\n")
+      : ""
+
+    const hasFailures = failedTasks.length > 0
+    const header = hasFailures
+      ? `[ALL BACKGROUND TASKS FINISHED - ${failedTasks.length} FAILED]`
+      : "[ALL BACKGROUND TASKS COMPLETE]"
+
+    let body = ""
+    if (succeededText) {
+      body += `**Completed:**\n${succeededText}\n`
+    }
+    if (failedText) {
+      body += `\n**Failed:**\n${failedText}\n`
+    }
+    if (!body) {
+      body = `- \`${task.id}\`: ${task.description} [${task.status.toUpperCase()}]${task.error ? ` - ${task.error}` : ""}\n`
+    }
 
     return `<system-reminder>
-[ALL BACKGROUND TASKS COMPLETE]
+${header}
 
-**Completed:**
-${completedTasksText || `- \`${task.id}\`: ${task.description}`}
+${body.trim()}
 
-Use \`background_output(task_id="<id>")\` to retrieve each result.
+Use \`background_output(task_id="<id>")\` to retrieve each result.${hasFailures ? `\n\n**ACTION REQUIRED:** ${failedTasks.length} task(s) failed. Check errors above and decide whether to retry or proceed.` : ""}
 </system-reminder>`
   }
 
   const agentInfo = task.category ? `${task.agent} (${task.category})` : task.agent
+  const isFailure = statusText !== "COMPLETED"
 
   return `<system-reminder>
 [BACKGROUND TASK ${statusText}]
@@ -39,7 +61,7 @@ Use \`background_output(task_id="<id>")\` to retrieve each result.
 **Duration:** ${duration}${errorInfo}
 
 **${remainingCount} task${remainingCount === 1 ? "" : "s"} still in progress.** You WILL be notified when ALL complete.
-Do NOT poll - continue productive work.
+${isFailure ? "**ACTION REQUIRED:** This task failed. Check the error and decide whether to retry, cancel remaining tasks, or continue." : "Do NOT poll - continue productive work."}
 
 Use \`background_output(task_id="${task.id}")\` to retrieve this result when ready.
 </system-reminder>`
diff --git a/src/features/background-agent/manager.test.ts b/src/features/background-agent/manager.test.ts
index 8994abd34..974718387 100644
--- a/src/features/background-agent/manager.test.ts
+++ b/src/features/background-agent/manager.test.ts
@@ -3478,12 +3478,12 @@ describe("BackgroundManager.checkAndInterruptStaleTasks", () => {
     //#when — no progress update for 15 minutes
     await manager["checkAndInterruptStaleTasks"]({})
 
-    //#then — killed after messageStalenessTimeout
+    //#then — killed because session gone from status registry
     expect(task.status).toBe("cancelled")
-    expect(task.error).toContain("no activity")
+    expect(task.error).toContain("session gone from status registry")
   })
 
-  test("should NOT interrupt task with no lastUpdate within messageStalenessTimeout", async () => {
+  test("should NOT interrupt task with no lastUpdate within session-gone timeout", async () => {
     //#given
     const client = {
       session: {
@@ -3492,7 +3492,7 @@ describe("BackgroundManager.checkAndInterruptStaleTasks", () => {
         abort: async () => ({}),
       },
     }
-    const manager = new BackgroundManager({ client, directory: tmpdir() } as unknown as PluginInput, { messageStalenessTimeoutMs: 600_000 })
+    const manager = new BackgroundManager({ client, directory: tmpdir() } as unknown as PluginInput, { messageStalenessTimeoutMs: 600_000, sessionGoneTimeoutMs: 600_000 })
 
     const task: BackgroundTask = {
       id: "task-fresh-no-update",
@@ -3509,7 +3509,7 @@ describe("BackgroundManager.checkAndInterruptStaleTasks", () => {
 
     getTaskMap(manager).set(task.id, task)
 
-    //#when — only 5 min since start, within 10min timeout
+    //#when — only 5 min since start, within 10min session-gone timeout
     await manager["checkAndInterruptStaleTasks"]({})
 
     //#then — task survives
@@ -4263,7 +4263,7 @@ describe("BackgroundManager.pruneStaleTasksAndNotifications - removes pruned tas
     expect(retainedTask?.status).toBe("error")
     expect(getTaskMap(manager).has(staleTask.id)).toBe(true)
     expect(notifications).toHaveLength(1)
-    expect(notifications[0]).toContain("[ALL BACKGROUND TASKS COMPLETE]")
+    expect(notifications[0]).toContain("[ALL BACKGROUND TASKS FINISHED")
     expect(notifications[0]).toContain(staleTask.description)
     expect(getCompletionTimers(manager).has(staleTask.id)).toBe(true)
     expect(removeTaskCalls).toContain(staleTask.id)
diff --git a/src/features/background-agent/manager.ts b/src/features/background-agent/manager.ts
index 980061bb6..cb288f317 100644
--- a/src/features/background-agent/manager.ts
+++ b/src/features/background-agent/manager.ts
@@ -147,7 +147,7 @@ export class BackgroundManager {
   private queuesByKey: Map<string, QueueItem[]> = new Map()
   private processingKeys: Set<string> = new Set()
   private completionTimers: Map<string, ReturnType<typeof setTimeout>> = new Map()
-  private completedTaskSummaries: Map<string, Array<{id: string, description: string}>> = new Map()
+  private completedTaskSummaries: Map<string, Array<{id: string, description: string, status: string, error?: string}>> = new Map()
   private idleDeferralTimers: Map<string, ReturnType<typeof setTimeout>> = new Map()
   private notificationQueueByParent: Map<string, Promise<void>> = new Map()
   private rootDescendantCounts: Map<string, number>
@@ -1552,6 +1552,8 @@ export class BackgroundManager {
     this.completedTaskSummaries.get(task.parentSessionID)!.push({
       id: task.id,
       description: task.description,
+      status: task.status,
+      error: task.error,
     })
 
     // Update pending tracking and check if all tasks complete
@@ -1573,7 +1575,7 @@ export class BackgroundManager {
     }
 
     const completedTasks = allComplete
-      ? (this.completedTaskSummaries.get(task.parentSessionID) ?? [{ id: task.id, description: task.description }])
+      ? (this.completedTaskSummaries.get(task.parentSessionID) ?? [{ id: task.id, description: task.description, status: task.status, error: task.error }])
       : []
 
     if (allComplete) {
@@ -1591,20 +1593,40 @@ export class BackgroundManager {
 
     let notification: string
     if (allComplete) {
-        const completedTasksText = completedTasks
-          .map(t => `- \`${t.id}\`: ${t.description}`)
-          .join("\n")
+        const succeededTasks = completedTasks.filter(t => t.status === "completed")
+        const failedTasks = completedTasks.filter(t => t.status !== "completed")
+
+        const succeededText = succeededTasks.length > 0
+          ? succeededTasks.map(t => `- \`${t.id}\`: ${t.description}`).join("\n")
+          : ""
+        const failedText = failedTasks.length > 0
+          ? failedTasks.map(t => `- \`${t.id}\`: ${t.description} [${t.status.toUpperCase()}]${t.error ? ` - ${t.error}` : ""}`).join("\n")
+          : ""
+
+        const hasFailures = failedTasks.length > 0
+        const header = hasFailures
+          ? `[ALL BACKGROUND TASKS FINISHED - ${failedTasks.length} FAILED]`
+          : "[ALL BACKGROUND TASKS COMPLETE]"
+
+        let body = ""
+        if (succeededText) {
+          body += `**Completed:**\n${succeededText}\n`
+        }
+        if (failedText) {
+          body += `\n**Failed:**\n${failedText}\n`
+        }
+        if (!body) {
+          body = `- \`${task.id}\`: ${task.description} [${task.status.toUpperCase()}]${task.error ? ` - ${task.error}` : ""}\n`
+        }
 
         notification = `<system-reminder>
-[ALL BACKGROUND TASKS COMPLETE]
+${header}
 
-**Completed:**
-${completedTasksText || `- \`${task.id}\`: ${task.description}`}
+${body.trim()}
 
-Use \`background_output(task_id="<id>")\` to retrieve each result.
+Use \`background_output(task_id="<id>")\` to retrieve each result.${hasFailures ? `\n\n**ACTION REQUIRED:** ${failedTasks.length} task(s) failed. Check errors above and decide whether to retry or proceed.` : ""}
 </system-reminder>`
     } else {
-      // Individual completion - silent notification
       notification = `<system-reminder>
 [BACKGROUND TASK ${statusText}]
 **ID:** \`${task.id}\`
@@ -1612,7 +1634,7 @@ Use \`background_output(task_id="<id>")\` to retrieve each result.
 **Duration:** ${duration}${errorInfo}
 
 **${remainingCount} task${remainingCount === 1 ? "" : "s"} still in progress.** You WILL be notified when ALL complete.
-Do NOT poll - continue productive work.
+${statusText === "COMPLETED" ? "Do NOT poll - continue productive work." : "**ACTION REQUIRED:** This task failed. Check the error and decide whether to retry, cancel remaining tasks, or continue."}
 
 Use \`background_output(task_id="${task.id}")\` to retrieve this result when ready.
 </system-reminder>`
@@ -1675,11 +1697,14 @@ Use \`background_output(task_id="${task.id}")\` to retrieve this result when rea
           resolvedModel: model,
         })
 
+        const isTaskFailure = task.status === "error" || task.status === "cancelled" || task.status === "interrupt"
+        const shouldReply = allComplete || isTaskFailure
+
         try {
           await this.client.session.promptAsync({
             path: { id: task.parentSessionID },
             body: {
-              noReply: !allComplete,
+              noReply: !shouldReply,
               ...(agent !== undefined ? { agent } : {}),
               ...(model !== undefined ? { model } : {}),
               ...(resolvedTools ? { tools: resolvedTools } : {}),
@@ -1689,7 +1714,8 @@ Use \`background_output(task_id="${task.id}")\` to retrieve this result when rea
           log("[background-agent] Sent notification to parent session:", {
             taskId: task.id,
             allComplete,
-            noReply: !allComplete,
+            isTaskFailure,
+            noReply: !shouldReply,
           })
         } catch (error) {
           if (isAbortedSessionError(error)) {
diff --git a/src/features/background-agent/task-poller.test.ts b/src/features/background-agent/task-poller.test.ts
index ec3d09a74..a99154ebf 100644
--- a/src/features/background-agent/task-poller.test.ts
+++ b/src/features/background-agent/task-poller.test.ts
@@ -288,29 +288,100 @@ describe("checkAndInterruptStaleTasks", () => {
     expect(task.status).toBe("running")
   })
 
-  it("should use default stale timeout when session status is unknown/missing", async () => {
-    //#given — lastUpdate exceeds stale timeout, session not in status map
+  it("should use session-gone timeout when session is missing from status map (with progress)", async () => {
+    //#given — lastUpdate 2min ago, session completely gone from status
     const task = createRunningTask({
       startedAt: new Date(Date.now() - 300_000),
       progress: {
         toolCalls: 1,
-        lastUpdate: new Date(Date.now() - 200_000),
+        lastUpdate: new Date(Date.now() - 120_000),
       },
     })
 
-    //#when — empty sessionStatuses (session not found)
+    //#when — empty sessionStatuses (session gone), sessionGoneTimeoutMs = 60s
     await checkAndInterruptStaleTasks({
       tasks: [task],
       client: mockClient as never,
-      config: { staleTimeoutMs: 180_000 },
+      config: { staleTimeoutMs: 180_000, sessionGoneTimeoutMs: 60_000 },
       concurrencyManager: mockConcurrencyManager as never,
       notifyParentSession: mockNotify,
       sessionStatuses: {},
     })
 
-    //#then — unknown session treated as potentially stale, apply default timeout
+    //#then — cancelled because session gone timeout (60s) < timeSinceLastUpdate (120s)
     expect(task.status).toBe("cancelled")
-    expect(task.error).toContain("Stale timeout")
+    expect(task.error).toContain("session gone from status registry")
+  })
+
+  it("should use session-gone timeout when session is missing from status map (no progress)", async () => {
+    //#given — task started 2min ago, no progress, session completely gone
+    const task = createRunningTask({
+      startedAt: new Date(Date.now() - 120_000),
+      progress: undefined,
+    })
+
+    //#when — session gone, sessionGoneTimeoutMs = 60s
+    await checkAndInterruptStaleTasks({
+      tasks: [task],
+      client: mockClient as never,
+      config: { messageStalenessTimeoutMs: 600_000, sessionGoneTimeoutMs: 60_000 },
+      concurrencyManager: mockConcurrencyManager as never,
+      notifyParentSession: mockNotify,
+      sessionStatuses: {},
+    })
+
+    //#then — cancelled because session gone timeout (60s) < runtime (120s)
+    expect(task.status).toBe("cancelled")
+    expect(task.error).toContain("session gone from status registry")
+  })
+
+  it("should NOT use session-gone timeout when session is idle (present in status map)", async () => {
+    //#given — lastUpdate 2min ago, session is idle (present in status but not active)
+    const task = createRunningTask({
+      startedAt: new Date(Date.now() - 300_000),
+      progress: {
+        toolCalls: 1,
+        lastUpdate: new Date(Date.now() - 120_000),
+      },
+    })
+
+    //#when — session is idle (present in map), staleTimeoutMs = 180s
+    await checkAndInterruptStaleTasks({
+      tasks: [task],
+      client: mockClient as never,
+      config: { staleTimeoutMs: 180_000, sessionGoneTimeoutMs: 60_000 },
+      concurrencyManager: mockConcurrencyManager as never,
+      notifyParentSession: mockNotify,
+      sessionStatuses: { "ses-1": { type: "idle" } },
+    })
+
+    //#then — still running because normal staleTimeout (180s) > timeSinceLastUpdate (120s)
+    expect(task.status).toBe("running")
+  })
+
+  it("should use default session-gone timeout when not configured", async () => {
+    //#given — lastUpdate 2min ago, session gone, no sessionGoneTimeoutMs config
+    const task = createRunningTask({
+      startedAt: new Date(Date.now() - 300_000),
+      progress: {
+        toolCalls: 1,
+        lastUpdate: new Date(Date.now() - 120_000),
+      },
+    })
+
+    //#when — no config (default sessionGoneTimeoutMs = 60_000)
+    await checkAndInterruptStaleTasks({
+      tasks: [task],
+      client: mockClient as never,
+      config: undefined,
+      concurrencyManager: mockConcurrencyManager as never,
+      notifyParentSession: mockNotify,
+      sessionStatuses: {},
+    })
+
+    //#then — cancelled because default session gone timeout (60s) < timeSinceLastUpdate (120s)
+    expect(task.status).toBe("cancelled")
+    expect(task.error).toContain("session gone from status registry")
   })
 
   it("should NOT interrupt task when session is busy (OpenCode status), even if lastUpdate exceeds stale timeout", async () => {
diff --git a/src/hooks/legacy-plugin-toast/auto-migrate.test.ts b/src/hooks/legacy-plugin-toast/auto-migrate.test.ts
index cdc03389f..d1aa5e745 100644
--- a/src/hooks/legacy-plugin-toast/auto-migrate.test.ts
+++ b/src/hooks/legacy-plugin-toast/auto-migrate.test.ts
@@ -10,12 +10,10 @@ describe("autoMigrateLegacyPluginEntry", () => {
   beforeEach(() => {
     testConfigDir = join(tmpdir(), `omo-legacy-migrate-${Date.now()}-${Math.random().toString(36).slice(2)}`)
     mkdirSync(testConfigDir, { recursive: true })
-    process.env.OPENCODE_CONFIG_DIR = testConfigDir
   })
 
   afterEach(() => {
     rmSync(testConfigDir, { recursive: true, force: true })
-    delete process.env.OPENCODE_CONFIG_DIR
   })
 
   describe("#given opencode.json has a bare legacy plugin entry", () => {
@@ -27,7 +25,7 @@ describe("autoMigrateLegacyPluginEntry", () => {
       )
 
       // when
-      const result = autoMigrateLegacyPluginEntry()
+      const result = autoMigrateLegacyPluginEntry(testConfigDir)
 
       // then
       expect(result.migrated).toBe(true)
@@ -47,7 +45,7 @@ describe("autoMigrateLegacyPluginEntry", () => {
       )
 
       // when
-      const result = autoMigrateLegacyPluginEntry()
+      const result = autoMigrateLegacyPluginEntry(testConfigDir)
 
       // then
       expect(result.migrated).toBe(true)
@@ -67,7 +65,7 @@ describe("autoMigrateLegacyPluginEntry", () => {
       )
 
       // when
-      const result = autoMigrateLegacyPluginEntry()
+      const result = autoMigrateLegacyPluginEntry(testConfigDir)
 
       // then
       expect(result.migrated).toBe(true)
@@ -81,7 +79,7 @@ describe("autoMigrateLegacyPluginEntry", () => {
       // given - empty dir
 
       // when
-      const result = autoMigrateLegacyPluginEntry()
+      const result = autoMigrateLegacyPluginEntry(testConfigDir)
 
       // then
       expect(result.migrated).toBe(false)
@@ -98,7 +96,7 @@ describe("autoMigrateLegacyPluginEntry", () => {
       )
 
       // when
-      const result = autoMigrateLegacyPluginEntry()
+      const result = autoMigrateLegacyPluginEntry(testConfigDir)
 
       // then
       expect(result.migrated).toBe(true)
@@ -116,7 +114,7 @@ describe("autoMigrateLegacyPluginEntry", () => {
       writeFileSync(join(testConfigDir, "opencode.json"), original)
 
       // when
-      const result = autoMigrateLegacyPluginEntry()
+      const result = autoMigrateLegacyPluginEntry(testConfigDir)
 
       // then
       expect(result.migrated).toBe(false)
diff --git a/src/hooks/legacy-plugin-toast/auto-migrate.ts b/src/hooks/legacy-plugin-toast/auto-migrate.ts
index 74aaf8c45..34bc4bbc0 100644
--- a/src/hooks/legacy-plugin-toast/auto-migrate.ts
+++ b/src/hooks/legacy-plugin-toast/auto-migrate.ts
@@ -1,4 +1,5 @@
 import { existsSync, readFileSync, writeFileSync } from "node:fs"
+import { join } from "node:path"
 
 import { parseJsoncSafe } from "../../shared/jsonc-parser"
 import { getOpenCodeConfigPaths } from "../../shared/opencode-config-dir"
@@ -31,15 +32,23 @@ function toLegacyCanonical(entry: string): string {
   return entry
 }
 
-function detectOpenCodeConfigPath(): string | null {
+function detectOpenCodeConfigPath(overrideConfigDir?: string): string | null {
+  if (overrideConfigDir) {
+    const jsoncPath = join(overrideConfigDir, "opencode.jsonc")
+    const jsonPath = join(overrideConfigDir, "opencode.json")
+    if (existsSync(jsoncPath)) return jsoncPath
+    if (existsSync(jsonPath)) return jsonPath
+    return null
+  }
+
   const paths = getOpenCodeConfigPaths({ binary: "opencode", version: null })
   if (existsSync(paths.configJsonc)) return paths.configJsonc
   if (existsSync(paths.configJson)) return paths.configJson
   return null
 }
 
-export function autoMigrateLegacyPluginEntry(): MigrationResult {
-  const configPath = detectOpenCodeConfigPath()
+export function autoMigrateLegacyPluginEntry(overrideConfigDir?: string): MigrationResult {
+  const configPath = detectOpenCodeConfigPath(overrideConfigDir)
   if (!configPath) return { migrated: false, from: null, to: null, configPath: null }
 
   try {