diff --git a/backend/tests/test_agent_teams_plugin.py b/backend/tests/test_agent_teams_plugin.py
index 0f790e9d6d..93f25c0be4 100644
--- a/backend/tests/test_agent_teams_plugin.py
+++ b/backend/tests/test_agent_teams_plugin.py
@@ -1,6 +1,7 @@
 """Team extension contracts exercised through the installed contribution."""
 
 import asyncio
+import json
 from pathlib import Path
 from types import SimpleNamespace
 
@@ -943,3 +944,107 @@ async def test_cancel_reconciles_a_clarification_response_with_lost_admission_ac
     view = await actions["get"]({"team_id": team["id"]}, context(runs))
     assert view["jobs"][0]["status"] == "cancelled"
     assert len(view["jobs"]) == 1 and len(runs.starts) == 2
+
+
+async def waiting_job(actions, service, runs, *, clarification=False):
+    """Park a job for either an explicit interrupt or an ordinary clarification."""
+    team = await create(actions, runs)
+    sent = await actions["send"]({"team_id": team["id"], "member_id": team["members"][0]["id"], "text": "Check release", "request_id": "one"}, context(runs))
+    await service.tick()
+    runs.finish(sent["id"], interrupted=not clarification)
+    if clarification:
+        from deerflow.agents.middlewares.clarification_middleware import ClarificationMiddleware
+
+        request = SimpleNamespace(tool_call={"name": "ask_clarification", "id": "question", "args": {"question": "Which environment?", "clarification_type": "missing_info"}}, runtime=None)
+        command = ClarificationMiddleware().wrap_tool_call(request, lambda _: pytest.fail("intercept clarification"))
+        runs.threads[team["members"][0]["thread_id"]]["values"]["messages"].extend(m.model_dump() for m in command.update["messages"])
+    await service.tick()
+    assert (await actions["get"]({"team_id": team["id"]}, context(runs)))["jobs"][0]["status"] == "waiting_input"
+    return team, sent
+
+
+@pytest.mark.asyncio
+@pytest.mark.parametrize(
+    "answer",
+    [
+        pytest.param("漢" * 2000, id="cjk-2000-chars"),
+        pytest.param("🙂" * 1000, id="emoji-1000-chars"),
+        pytest.param("a" * 4000, id="ascii-4000-chars"),
+        pytest.param('"' * 4000, id="json-quotes"),
+        pytest.param("\n" * 3999 + "a", id="json-newlines"),
+    ],
+)
+async def test_a_clarification_answer_within_the_documented_bounds_is_accepted(plugin, answer):
+    # README: tasks and clarification answers accept up to 4,000 characters / 8,000 UTF-8 bytes,
+    # and the UI validates exactly those two bounds before submitting.
+    _, actions, service = plugin
+    runs = Runs()
+    team, sent = await waiting_job(actions, service, runs)
+    await actions["resume"]({"team_id": team["id"], "job_id": sent["id"], "response": answer, "request_id": "answer"}, context(runs))
+    assert (await actions["get"]({"team_id": team["id"]}, context(runs)))["jobs"][0]["status"] == "resuming"
+
+
+@pytest.mark.asyncio
+@pytest.mark.parametrize("answer", ["漢" * 3000, {"text": "x" * 9000}])
+async def test_an_oversized_clarification_answer_is_still_refused(plugin, answer):
+    _, actions, service = plugin
+    runs = Runs()
+    team, sent = await waiting_job(actions, service, runs)
+    with pytest.raises(ValueError, match="8 KiB"):
+        await actions["resume"]({"team_id": team["id"], "job_id": sent["id"], "response": answer, "request_id": "answer"}, context(runs))
+    assert (await actions["get"]({"team_id": team["id"]}, context(runs)))["jobs"][0]["status"] == "waiting_input"
+
+
+@pytest.mark.asyncio
+@pytest.mark.parametrize("clarification", [False, True], ids=["interrupt", "clarification"])
+@pytest.mark.parametrize("size", [7999, 8000, 8001])
+async def test_string_response_uses_the_raw_utf8_byte_boundary(plugin, clarification, size):
+    _, actions, service = plugin
+    runs = Runs()
+    team, sent = await waiting_job(actions, service, runs, clarification=clarification)
+    answer = "漢" * 2666 + "a" * (size - 7998)
+    payload = {"team_id": team["id"], "job_id": sent["id"], "response": answer, "request_id": "answer"}
+    if size > 8000:
+        with pytest.raises(ValueError, match="8 KiB"):
+            await actions["resume"](payload, context(runs))
+    else:
+        await actions["resume"](payload, context(runs))
+    job = (await service.db("get", "alice", team["id"]))["jobs"][0]
+    assert job["status"] == ("waiting_input" if size > 8000 else "resuming")
+    if size <= 8000:
+        assert job["resume"]["response"] == answer
+        if clarification:
+            assert job["resume"]["input"]["messages"][0]["content"] == answer
+
+
+@pytest.mark.asyncio
+@pytest.mark.parametrize("size", [7999, 8000, 8001])
+async def test_structured_response_keeps_the_utf8_json_byte_boundary(plugin, size):
+    _, actions, service = plugin
+    runs = Runs()
+    team, sent = await waiting_job(actions, service, runs)
+    # The JSON object adds 12 bytes around its string value.
+    answer = {"text": "漢" * 2660 + "a" * (size - 7980 - 12)}
+    payload = {"team_id": team["id"], "job_id": sent["id"], "response": answer, "request_id": "answer"}
+    if size > 8000:
+        with pytest.raises(ValueError, match="8 KiB"):
+            await actions["resume"](payload, context(runs))
+    else:
+        await actions["resume"](payload, context(runs))
+    job = (await service.db("get", "alice", team["id"]))["jobs"][0]
+    assert job["status"] == ("waiting_input" if size > 8000 else "resuming")
+    if size <= 8000:
+        assert job["resume"]["response"] == answer
+
+
+@pytest.mark.asyncio
+@pytest.mark.parametrize("response_json", ['"\\ud800"', '"\\udc00"', '{"text": "\\ud800"}', '{"\\udc00": true}'])
+async def test_malformed_unicode_response_uses_the_friendly_validation_error(plugin, response_json):
+    _, actions, service = plugin
+    runs = Runs()
+    team, sent = await waiting_job(actions, service, runs)
+    with pytest.raises(ValueError, match="^An explicit response of at most 8 KiB is required$"):
+        await actions["resume"]({"team_id": team["id"], "job_id": sent["id"], "response": json.loads(response_json), "request_id": "answer"}, context(runs))
+    job = (await service.db("get", "alice", team["id"]))["jobs"][0]
+    assert job["status"] == "waiting_input"
+    assert job["resume"] is None
diff --git a/examples/deerflow-extension-agent-teams/AGENTS.md b/examples/deerflow-extension-agent-teams/AGENTS.md
index 48b3419d80..93b900ac28 100644
--- a/examples/deerflow-extension-agent-teams/AGENTS.md
+++ b/examples/deerflow-extension-agent-teams/AGENTS.md
@@ -27,6 +27,8 @@ backend character/UTF-8 byte limits. Use host theme tokens for action colors.
 Validate user-entered team names, goals, tasks and clarification answers against
 both backend bounds without truncating the draft. Native mention labels must fit
 the host's 120 UTF-16-unit limit; keep routing IDs independent of display labels.
+Measure string responses as raw UTF-8 and structured interrupt responses as UTF-8
+JSON. Reject malformed Unicode before changing a waiting job or admitting a run.
 
 Ordinary human-input artifacts end runs successfully without a graph interrupt.
 Keep unanswered requests waiting; persist text-response inputs and idempotency
diff --git a/examples/deerflow-extension-agent-teams/README.md b/examples/deerflow-extension-agent-teams/README.md
index fae4c6691e..e78685c101 100644
--- a/examples/deerflow-extension-agent-teams/README.md
+++ b/examples/deerflow-extension-agent-teams/README.md
@@ -109,7 +109,11 @@ own teams. Sharing a host conversation does **not** share its team's private dat
 - Team names accept up to 80 characters / 160 UTF-8 bytes; goals accept up to
   2,000 characters / 4,000 UTF-8 bytes. Tasks and clarification answers accept
   up to 4,000 characters / 8,000 UTF-8 bytes. The UI validates both bounds before
-  submission and preserves oversized text for editing. Native mention labels
+  submission and preserves oversized text for editing. String answers count their
+  raw UTF-8 bytes, including the 8,000-byte ceiling; JSON quotes and escapes do not
+  reduce that allowance. Structured graph-interrupt responses retain an 8,000-byte
+  UTF-8 JSON limit. Responses with unpaired Unicode surrogates are rejected through
+  the normal response validation. Native mention labels
   fall back to the member name when the combined team/member label exceeds the
   host's 120 UTF-16-unit limit; selection still routes by team/member IDs.
   Shared context contains
@@ -151,7 +155,9 @@ creation), request capacity independent of receipts, ambiguous admission, and
 lifecycle locking. Host-run transport is controlled for deterministic tests.
 Clarification tests execute the host's real tool and middleware in an Agent graph,
 including repeated questions, peer/mention/result-receipt paths, lost response
-acknowledgements and restart. Queued-request regressions pin handoff attribution
+acknowledgements and restart. Response regressions cover the 7,999/8,000/8,001-byte
+boundaries for both input paths, structured JSON, escaping and malformed Unicode.
+Queued-request regressions pin handoff attribution
 and the chain limit while the first request is running or awaiting admission acknowledgement.
 
 For a browser check, install the repo's frontend dependencies, then start the
diff --git a/examples/deerflow-extension-agent-teams/deerflow_extension_agent_teams/service.py b/examples/deerflow-extension-agent-teams/deerflow_extension_agent_teams/service.py
index 2b13411ca2..54b9dd3f74 100644
--- a/examples/deerflow-extension-agent-teams/deerflow_extension_agent_teams/service.py
+++ b/examples/deerflow-extension-agent-teams/deerflow_extension_agent_teams/service.py
@@ -318,7 +318,13 @@ class Teams:
 
     async def resume(self, payload, context):
         fields(payload, "team_id job_id response request_id")
-        if payload["response"] is None or len(json.dumps(payload["response"]).encode()) > 8000:
+        response = payload["response"]
+        try:
+            content = response if isinstance(response, str) else json.dumps(response, ensure_ascii=False)
+            valid = response is not None and len(content.encode("utf-8")) <= 8000
+        except UnicodeEncodeError:
+            valid = False
+        if not valid:
             raise ValueError("An explicit response of at most 8 KiB is required")
         text(payload, "request_id", 128)
         return await self.control(payload, context, cancel=False)