diff --git a/src/tools/background-task/council-result-format.ts b/src/tools/background-task/council-result-format.ts
new file mode 100644
index 000000000..262793dd8
--- /dev/null
+++ b/src/tools/background-task/council-result-format.ts
@@ -0,0 +1,82 @@
+import type { BackgroundTask } from "../../features/background-agent"
+import { COUNCIL_MEMBER_KEY_PREFIX } from "../../agents/builtin-agents/council-member-agents"
+import type { BackgroundOutputClient } from "./clients"
+import { extractMessages, getErrorMessage } from "./session-messages"
+
+const OPENING_TAG = "<COUNCIL_MEMBER_RESPONSE>"
+const CLOSING_TAG = "</COUNCIL_MEMBER_RESPONSE>"
+
+export interface CouncilTaskResult {
+  has_response: boolean
+  response_complete: boolean
+  result: string | null
+  session_id: string | null
+}
+
+export function isCouncilTask(task: BackgroundTask): boolean {
+  return task.agent?.startsWith(COUNCIL_MEMBER_KEY_PREFIX) ?? false
+}
+
+function getTimeString(value: unknown): string {
+  return typeof value === "string" ? value : ""
+}
+
+function extractCouncilResponse(fullText: string): CouncilTaskResult & { session_id: null } {
+  const lastOpenIdx = fullText.lastIndexOf(OPENING_TAG)
+  if (lastOpenIdx === -1) {
+    return { has_response: false, response_complete: false, result: null, session_id: null }
+  }
+
+  const contentStart = lastOpenIdx + OPENING_TAG.length
+  const closingAfterLastOpen = fullText.indexOf(CLOSING_TAG, contentStart)
+
+  if (closingAfterLastOpen === -1) {
+    const partial = fullText.slice(contentStart).trim()
+    return { has_response: true, response_complete: false, result: partial || null, session_id: null }
+  }
+
+  const content = fullText.slice(contentStart, closingAfterLastOpen).trim()
+  return { has_response: true, response_complete: true, result: content, session_id: null }
+}
+
+export async function formatCouncilTaskResult(
+  task: BackgroundTask,
+  client: BackgroundOutputClient,
+): Promise<CouncilTaskResult> {
+  if (!task.sessionID) {
+    return { has_response: false, response_complete: false, result: null, session_id: null }
+  }
+
+  const messagesResult = await client.session.messages({ path: { id: task.sessionID } })
+
+  const errorMessage = getErrorMessage(messagesResult)
+  if (errorMessage) {
+    return { has_response: false, response_complete: false, result: null, session_id: task.sessionID }
+  }
+
+  const messages = extractMessages(messagesResult)
+  if (!Array.isArray(messages) || messages.length === 0) {
+    return { has_response: false, response_complete: false, result: null, session_id: task.sessionID }
+  }
+
+  const assistantMessages = messages.filter((m) => m.info?.role === "assistant")
+  const sorted = [...assistantMessages].sort((a, b) => {
+    const timeA = getTimeString(a.info?.time)
+    const timeB = getTimeString(b.info?.time)
+    return timeA.localeCompare(timeB)
+  })
+
+  const textParts: string[] = []
+  for (const message of sorted) {
+    for (const part of message.parts ?? []) {
+      if ((part.type === "text" || part.type === "reasoning") && part.text) {
+        textParts.push(part.text)
+      }
+    }
+  }
+
+  const fullText = textParts.join("\n\n")
+  const extracted = extractCouncilResponse(fullText)
+
+  return { ...extracted, session_id: task.sessionID }
+}