diff --git a/tests/tools/test_async_delegation.py b/tests/tools/test_async_delegation.py
index 238ed6f159..d91ff87990 100644
--- a/tests/tools/test_async_delegation.py
+++ b/tests/tools/test_async_delegation.py
@@ -761,3 +761,67 @@ def test_gateway_cli_origin_event_left_unrouted():
     runner._enrich_async_delegation_routing(evt)
     assert "platform" not in evt
 
+
+def test_single_task_truncation_banner_when_max_iterations():
+    """A single async subagent that hit its iteration cap (exit_reason=
+    max_iterations) must surface a TRUNCATED marker in the formatted result,
+    even though status stays 'completed' (a summary exists)."""
+    evt = _make_async_evt(
+        status="completed",
+        summary="Did part of the work then ran out of budget.",
+        exit_reason="max_iterations",
+    )
+    text = format_process_notification(evt)
+    assert text is not None
+    assert "TRUNCATED" in text
+    assert "max_iterations" in text
+    # The summary is still shown, just flagged.
+    assert "Did part of the work" in text
+
+
+def test_single_task_no_banner_when_clean():
+    """A cleanly-finished subagent must NOT get a truncation banner."""
+    evt = _make_async_evt(status="completed", summary="All done.", exit_reason="completed")
+    text = format_process_notification(evt)
+    assert text is not None
+    assert "TRUNCATED" not in text
+
+
+def test_batch_truncation_banner_marks_only_truncated_task():
+    """In a batch, only the task that hit max_iterations gets the TRUNCATED
+    marker; a clean sibling keeps the normal check icon."""
+    evt = _make_async_evt(
+        is_batch=True,
+        goals=["clean task", "truncated task"],
+        results=[
+            {
+                "task_index": 0,
+                "status": "completed",
+                "summary": "finished cleanly",
+                "api_calls": 5,
+                "exit_reason": "completed",
+                "truncated": False,
+            },
+            {
+                "task_index": 1,
+                "status": "completed",
+                "summary": "cut off mid-work",
+                "api_calls": 250,
+                "exit_reason": "max_iterations",
+                "truncated": True,
+            },
+        ],
+    )
+    text = format_process_notification(evt)
+    assert text is not None
+    assert "TRUNCATED" in text
+    # The clean task's summary and the truncated one's both render...
+    assert "finished cleanly" in text
+    assert "cut off mid-work" in text
+    # ...but the banner is tied to the truncated task, not the clean one.
+    trunc_pos = text.index("cut off mid-work")
+    clean_pos = text.index("finished cleanly")
+    banner_pos = text.index("TRUNCATED")
+    # The header banner for task 2 appears after task 1's summary.
+    assert banner_pos > clean_pos
+
diff --git a/tools/delegate_tool.py b/tools/delegate_tool.py
index 0477c9c921..c84c82592c 100644
--- a/tools/delegate_tool.py
+++ b/tools/delegate_tool.py
@@ -2870,6 +2870,13 @@ def _run_single_child(
             "duration_seconds": duration,
             "model": _model if isinstance(_model, str) else None,
             "exit_reason": exit_reason,
+            # Explicit, parent-visible truncation flag. A subagent that
+            # exhausts its per-child iteration budget still returns a summary,
+            # so `status` stays "completed" (see above) — without this the
+            # parent can't tell truncated-but-summarized from cleanly-finished
+            # work except by parsing the summary prose. exit_reason is computed
+            # authoritatively from the child's `completed` flag.
+            "truncated": exit_reason == "max_iterations",
             "tokens": {
                 "input": (
                     _input_tokens if isinstance(_input_tokens, (int, float)) else 0
diff --git a/tools/process_registry.py b/tools/process_registry.py
index 6babfe69df..309edf6350 100644
--- a/tools/process_registry.py
+++ b/tools/process_registry.py
@@ -2695,6 +2695,7 @@ def _format_async_delegation(evt: dict) -> str:
     error = evt.get("error")
     api_calls = evt.get("api_calls", 0)
     duration = evt.get("duration_seconds", "?")
+    truncated = evt.get("truncated") or evt.get("exit_reason") == "max_iterations"
     dispatched_at = evt.get("dispatched_at")
     completed_at = evt.get("completed_at") or _time.time()
 
@@ -2735,7 +2736,8 @@ def _format_async_delegation(evt: dict) -> str:
             r_summary = r.get("summary")
             r_error = r.get("error")
             r_goal = goals[idx] if idx < len(goals) else r.get("goal", "")
-            icon = "✓" if r_status in ("completed", "success") else "✗"
+            r_truncated = r.get("truncated") or r.get("exit_reason") == "max_iterations"
+            icon = "⚠" if r_truncated else ("✓" if r_status in ("completed", "success") else "✗")
             lines.append("")
             header = f"--- {icon} TASK {idx + 1}/{n}"
             if r_goal:
@@ -2745,9 +2747,17 @@ def _format_async_delegation(evt: dict) -> str:
                 header += f", api_calls={r['api_calls']}"
             if r.get("duration_seconds") is not None:
                 header += f", {r['duration_seconds']}s"
+            if r_truncated:
+                header += ", TRUNCATED: hit max_iterations — work may be incomplete"
             header += ") ---"
             lines.append(header)
             if r_status in ("completed", "success") and r_summary:
+                if r_truncated:
+                    lines.append(
+                        "[TRUNCATED — subagent hit its iteration cap; the "
+                        "summary below may be incomplete. Verify before relying "
+                        "on it, or re-dispatch the unfinished part.]"
+                    )
                 lines.append(r_summary)
             elif r_summary:
                 if r_error:
@@ -2787,9 +2797,16 @@ def _format_async_delegation(evt: dict) -> str:
     if toolsets:
         lines.append(f"Toolsets: {', '.join(toolsets)}")
     lines.append(f"Role: {role}   Model: {model}")
-    lines.append(f"Status: {status}   API calls: {api_calls}   Duration: {duration}s")
+    _trunc = " [TRUNCATED: hit max_iterations — work may be incomplete]" if truncated else ""
+    lines.append(f"Status: {status}   API calls: {api_calls}   Duration: {duration}s{_trunc}")
     lines.append("--- RESULT ---")
     if status in ("completed", "success") and summary:
+        if truncated:
+            lines.append(
+                "[TRUNCATED — subagent hit its iteration cap; the summary below "
+                "may be incomplete. Verify before relying on it, or re-dispatch "
+                "the unfinished part.]"
+            )
         lines.append(summary)
     elif status == "interrupted":
         lines.append(