diff --git a/src/tools/delegate-task/unstable-agent-task.terminal-fast-path.test.ts b/src/tools/delegate-task/unstable-agent-task.terminal-fast-path.test.ts
new file mode 100644
index 000000000..44eb4cb3a
--- /dev/null
+++ b/src/tools/delegate-task/unstable-agent-task.terminal-fast-path.test.ts
@@ -0,0 +1,67 @@
+/// <reference types="bun-types" />
+import { describe, expect, test } from "bun:test"
+import { unsafeTestValue } from "../../../test-support/unsafe-test-value"
+import { executeUnstableAgentTask } from "./unstable-agent-task"
+import type { DelegateTaskArgs } from "./types"
+
+const args: DelegateTaskArgs = {
+  description: "terminal task",
+  prompt: "do it",
+  category: "quick",
+  load_skills: [],
+  run_in_background: false,
+}
+
+describe("executeUnstableAgentTask terminal fast path", () => {
+  test("#given launched task is already interrupted #when monitoring starts #then it returns without waiting for the poll interval", async () => {
+    // given
+    const startedAt = Date.now()
+
+    // when
+    const output = await executeUnstableAgentTask(
+      args,
+      {
+        sessionID: "ses_parent",
+        messageID: "msg_parent",
+        agent: "sisyphus",
+        abort: new AbortController().signal,
+      },
+      unsafeTestValue({
+        manager: {
+          launch: async () => ({
+            id: "bg_terminal",
+            sessionId: "ses_terminal",
+            description: "terminal task",
+            agent: "sisyphus-junior",
+            status: "interrupt",
+            error: "already stopped",
+          }),
+          getTask: () => ({
+            id: "bg_terminal",
+            sessionId: "ses_terminal",
+            description: "terminal task",
+            agent: "sisyphus-junior",
+            status: "interrupt",
+            error: "already stopped",
+          }),
+        },
+        client: {
+          session: {
+            status: async () => ({ data: {} }),
+            messages: async () => ({ data: [] }),
+          },
+        },
+      }),
+      { sessionID: "ses_parent", messageID: "msg_parent", agent: "sisyphus" },
+      "sisyphus-junior",
+      undefined,
+      undefined,
+      "test-model",
+    )
+
+    // then
+    expect(Date.now() - startedAt).toBeLessThan(200)
+    expect(output).toContain("SUPERVISED TASK FAILED")
+    expect(output).toContain("already stopped")
+  })
+})
diff --git a/src/tools/delegate-task/unstable-agent-task.ts b/src/tools/delegate-task/unstable-agent-task.ts
index 0f9c026dd..e34ce20fe 100644
--- a/src/tools/delegate-task/unstable-agent-task.ts
+++ b/src/tools/delegate-task/unstable-agent-task.ts
@@ -108,13 +108,19 @@ export async function executeUnstableAgentTask(
         return `Task aborted (was running in background mode).\n\nSession ID: ${sessionID}`
       }
 
-      await new Promise(resolve => setTimeout(resolve, timingCfg.POLL_INTERVAL_MS))
-
       const currentTask = manager.getTask(task.id)
       if (currentTask && (currentTask.status === "interrupt" || currentTask.status === "error" || currentTask.status === "cancelled")) {
         terminalStatus = { status: currentTask.status, error: currentTask.error }
         break
       }
+      if (currentTask?.status === "completed") {
+        completedDuringMonitoring = true
+        break
+      }
+
+      const timeoutBudgetMs = syncPollTimeoutMs ?? DEFAULT_SYNC_POLL_TIMEOUT_MS
+      const remainingBudgetMs = timeoutBudgetMs - (Date.now() - pollStart)
+      await new Promise(resolve => setTimeout(resolve, Math.min(timingCfg.POLL_INTERVAL_MS, Math.max(1, remainingBudgetMs))))
 
       const statusResult = await client.session.status()
       const allStatuses = normalizeSDKResponse(statusResult, {} as Record<string, { type: string }>)