fix(tui): keep background marker with subagent label (#30271)

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

@@ -2218,9 +2218,13 @@ function Task(props: ToolProps<typeof TaskTool>) {
 
   const content = createMemo(() => {
     if (!props.input.description) return ""
-    const description =
-      props.metadata.background === true ? `${props.input.description} (background)` : props.input.description
-    let content = [`${Locale.titlecase(props.input.subagent_type ?? "General")} Task — ${description}`]
+    let content = [
+      formatSubagentTitle(
+        Locale.titlecase(props.input.subagent_type ?? "General"),
+        props.input.description,
+        props.metadata.background === true,
+      ),
+    ]
 
     const retrying = retry()
     if (isRunning() && retrying) {
@@ -2266,6 +2270,10 @@ export function formatSubagentToolcalls(count: number) {
   return `${count} toolcall${count === 1 ? "" : "s"}`
 }
 
+export function formatSubagentTitle(agent: string, description: string, background: boolean) {
+  return `${agent} Task${background ? " (background)" : ""} — ${description}`
+}
+
 export function formatCompletedSubagentDetail(toolcalls: number, duration: string) {
   if (toolcalls === 0) return duration
   return `${formatSubagentToolcalls(toolcalls)} · ${duration}`

packages/opencode/test/cli/tui/inline-tool-wrap-snapshot.test.tsx

@@ -3,6 +3,7 @@ import { For } from "solid-js"
 import { testRender, type JSX } from "@opentui/solid"
 import {
   formatCompletedSubagentDetail,
+  formatSubagentTitle,
   formatSubagentToolcalls,
   InlineToolRow,
 } from "../../../src/cli/cmd/tui/routes/session/index"
@@ -147,6 +148,13 @@ describe("TUI inline tool wrapping", () => {
     expect(formatSubagentToolcalls(0)).toBe("0 toolcalls")
   })
 
+  test("keeps background state attached to the subagent identity", () => {
+    expect(formatSubagentTitle("Explore", "Inspect renderer", false)).toBe("Explore Task — Inspect renderer")
+    expect(formatSubagentTitle("Explore", "Inspect renderer", true)).toBe(
+      "Explore Task (background) — Inspect renderer",
+    )
+  })
+
   test("snapshots consecutive grep, glob, and read rows at a narrow width", async () => {
     expect(await renderFrame(() => <Fixture />, { width: 72, height: 12 })).toMatchSnapshot()
   })