implement background agents

packages/opencode/src/cli/cmd/tui/routes/session/index.tsx

@@ -129,14 +129,40 @@ export function Session() {
       .toSorted((a, b) => (a.id < b.id ? -1 : a.id > b.id ? 1 : 0))
   })
   const messages = createMemo(() => sync.data.message[route.sessionID] ?? [])
+  const localPermissions = createMemo(() => sync.data.permission[route.sessionID] ?? [])
+  const localQuestions = createMemo(() => sync.data.question[route.sessionID] ?? [])
+  const childSessions = createMemo(() => {
+    if (session()?.parentID) return []
+    return children().filter((x) => x.id !== route.sessionID)
+  })
   const permissions = createMemo(() => {
     if (session()?.parentID) return []
-    return children().flatMap((x) => sync.data.permission[x.id] ?? [])
+    const child = childSessions().flatMap((x) => sync.data.permission[x.id] ?? [])
+    return [...localPermissions(), ...child]
   })
   const questions = createMemo(() => {
     if (session()?.parentID) return []
-    return children().flatMap((x) => sync.data.question[x.id] ?? [])
+    const child = childSessions().flatMap((x) => sync.data.question[x.id] ?? [])
+    return [...localQuestions(), ...child]
   })
+  const activeSubagents = createMemo(() =>
+    childSessions().flatMap((item) => {
+      const status = sync.data.session_status?.[item.id]
+      if (status?.type !== "busy" && status?.type !== "retry") return []
+      const count = (sync.data.message[item.id] ?? [])
+        .flatMap((message) => sync.data.part[message.id] ?? [])
+        .filter(
+          (part) => part.type === "tool" && (part.state.status === "completed" || part.state.status === "error"),
+        ).length
+      return [
+        {
+          session: item,
+          status,
+          count,
+        },
+      ]
+    }),
+  )
 
   const pending = createMemo(() => {
     return messages().findLast((x) => x.role === "assistant" && !x.time.completed)?.id
@@ -1150,14 +1176,37 @@ export function Session() {
               </For>
             </scrollbox>
             <box flexShrink={0}>
+              <Show when={activeSubagents().length > 0}>
+                <box paddingLeft={3} paddingBottom={1} gap={0}>
+                  <text fg={theme.text}>
+                    <span style={{ fg: theme.textMuted }}>Subagents</span> {activeSubagents().length} running
+                    <span style={{ fg: theme.textMuted }}> · {keybind.print("session_child_cycle")} open</span>
+                  </text>
+                  <For each={activeSubagents()}>
+                    {(item) => (
+                      <text
+                        fg={theme.textMuted}
+                        onMouseUp={() => {
+                          navigate({
+                            type: "session",
+                            sessionID: item.session.id,
+                          })
+                        }}
+                      >
+                        ↳ {Locale.truncate(item.session.title, 36)} · {item.count} toolcalls
+                      </text>
+                    )}
+                  </For>
+                </box>
+              </Show>
               <Show when={permissions().length > 0}>
                 <PermissionPrompt request={permissions()[0]} />
               </Show>
               <Show when={permissions().length === 0 && questions().length > 0}>
                 <QuestionPrompt request={questions()[0]} />
               </Show>
               <Prompt
-                visible={!session()?.parentID && permissions().length === 0 && questions().length === 0}
+                visible={!session()?.parentID && localPermissions().length === 0 && localQuestions().length === 0}
                 ref={(r) => {
                   prompt = r
                   promptRef.set(r)
@@ -1166,7 +1215,7 @@ export function Session() {
                     r.set(route.initialPrompt)
                   }
                 }}
-                disabled={permissions().length > 0 || questions().length > 0}
+                disabled={localPermissions().length > 0 || localQuestions().length > 0}
                 onSubmit={() => {
                   toBottom()
                 }}
@@ -1953,10 +2002,8 @@ function WebSearch(props: ToolProps<any>) {
 }
 
 function Task(props: ToolProps<typeof TaskTool>) {
-  const { theme } = useTheme()
   const keybind = useKeybind()
   const { navigate } = useRoute()
-  const local = useLocal()
   const sync = useSync()
 
   onMount(() => {
@@ -1974,9 +2021,47 @@ function Task(props: ToolProps<typeof TaskTool>) {
     )
   })
 
-  const current = createMemo(() => tools().findLast((x) => (x.state as any).title))
-
-  const isRunning = createMemo(() => props.part.state.status === "running")
+  const current = createMemo(() => tools().findLast((x) => x.state.status !== "pending"))
+  const background = createMemo(() => props.metadata.background === true)
+  const status = createMemo(() => {
+    const sessionID = props.metadata.sessionId
+    if (!sessionID) return
+    return sync.data.session_status?.[sessionID]
+  })
+  const counts = createMemo(() => {
+    const all = tools()
+    const done = all.filter((item) => item.state.status === "completed" || item.state.status === "error").length
+    return {
+      all: all.length,
+      done,
+    }
+  })
+  const childRunning = createMemo(() => status()?.type === "busy" || status()?.type === "retry")
+  const latest = createMemo(() => {
+    const user = messages().findLast((msg) => msg.role === "user")
+    const assistant = messages().findLast((msg) => msg.role === "assistant")
+    return {
+      user,
+      assistant,
+    }
+  })
+  const terminal = createMemo(() => {
+    const assistant = latest().assistant
+    if (!assistant) return false
+    const user = latest().user
+    if (user && user.id > assistant.id) return false
+    if (assistant.error) return true
+    return !!assistant.finish && !["tool-calls", "unknown"].includes(assistant.finish)
+  })
+  const backgroundRunning = createMemo(() => background() && childRunning())
+  const failed = createMemo(() => !!background() && terminal() && !!latest().assistant?.error)
+  const statusLabel = createMemo(() => {
+    if (backgroundRunning()) return "running in background"
+    if (!terminal()) return "background task pending sync"
+    if (failed()) return "background task failed"
+    return "background task finished"
+  })
+  const isRunning = createMemo(() => props.part.state.status === "running" || childRunning())
 
   const duration = createMemo(() => {
     const first = messages().find((x) => x.role === "user")?.time.created
@@ -1987,16 +2072,21 @@ function Task(props: ToolProps<typeof TaskTool>) {
 
   const content = createMemo(() => {
     if (!props.input.description) return ""
-    let content = [`Task ${props.input.description}`]
+    const toolLabel = `${childRunning() ? counts().done : counts().all} toolcalls`
+    const content = [`Task ${props.input.description}`]
+
+    if (background()) content.push(`↳ ${statusLabel()}`)
 
     if (isRunning() && tools().length > 0) {
-      // content[0] += ` · ${tools().length} toolcalls`
-      if (current()) content.push(`↳ ${Locale.titlecase(current()!.tool)} ${(current()!.state as any).title}`)
-      else content.push(`↳ ${tools().length} toolcalls`)
+      const title = current() && (current()!.state as any).title
+      if (title) content.push(`↳ ${Locale.titlecase(current()!.tool)} ${title}`)
+      else content.push(`↳ ${toolLabel}`)
     }
 
     if (props.part.state.status === "completed") {
-      content.push(`└ ${tools().length} toolcalls · ${Locale.duration(duration())}`)
+      content.push(`└ ${toolLabel} · ${Locale.duration(duration())}`)
+    } else if (props.metadata.sessionId) {
+      content.push(`└ ${keybind.print("session_child_cycle")} view subagents`)
     }
 
     return content.join("\n")

packages/opencode/src/tool/registry.ts

@@ -7,6 +7,7 @@ import { GrepTool } from "./grep"
 import { BatchTool } from "./batch"
 import { ReadTool } from "./read"
 import { TaskTool } from "./task"
+import { TaskStatusTool } from "./task_status"
 import { TodoWriteTool, TodoReadTool } from "./todo"
 import { WebFetchTool } from "./webfetch"
 import { WriteTool } from "./write"
@@ -110,6 +111,7 @@ export namespace ToolRegistry {
       EditTool,
       WriteTool,
       TaskTool,
+      TaskStatusTool,
       WebFetchTool,
       TodoWriteTool,
       // TodoReadTool,