diff --git a/backend/packages/harness/deerflow/community/infoquest/tools.py b/backend/packages/harness/deerflow/community/infoquest/tools.py
index 5f08ffb5b6..a1f4011719 100644
--- a/backend/packages/harness/deerflow/community/infoquest/tools.py
+++ b/backend/packages/harness/deerflow/community/infoquest/tools.py
@@ -1,4 +1,5 @@
 import asyncio
+import logging
 
 from langchain.tools import tool
 
@@ -7,30 +8,67 @@ from deerflow.utils.readability import ReadabilityExtractor
 
 from .infoquest_client import InfoQuestClient
 
+logger = logging.getLogger(__name__)
+
 readability_extractor = ReadabilityExtractor()
 
+# config.example.yaml documents -1 as "no time filtering" for every option below.
+_NO_TIME_FILTER = -1
+
+
+def _coerce_seconds(value: object, option: str) -> int:
+    """Normalize one of the documented crawl timeouts before handing it to the client.
+
+    ``$VAR`` references in config.yaml resolve verbatim from the environment, so a
+    configured ``timeout: $FETCH_TIMEOUT`` arrives as ``"10"``. The client compares each
+    of these options with ``0``, which raises for a string, ``None`` or a mapping and
+    takes the whole ``web_fetch``/``web_search``/``image_search`` call down with it.
+    Only an integer, an integral float or an integer-form string is accepted: plain
+    ``int()`` would silently truncate ``3.5`` and turn ``true`` into 1. Anything else
+    warns and keeps the documented default instead.
+    """
+    seconds: int | None
+    if isinstance(value, bool):
+        seconds = None
+    elif isinstance(value, int):
+        seconds = value
+    elif isinstance(value, float):
+        seconds = int(value) if value.is_integer() else None
+    elif isinstance(value, str):
+        try:
+            seconds = int(value.strip())
+        except ValueError:
+            seconds = None
+    else:
+        seconds = None
+
+    if seconds is None:
+        logger.warning("Invalid InfoQuest %s=%r; using default %s", option, value, _NO_TIME_FILTER)
+        return _NO_TIME_FILTER
+    return seconds
+
 
 def _get_infoquest_client() -> InfoQuestClient:
     search_config = get_app_config().get_tool_config("web_search")
-    search_time_range = -1
+    search_time_range = _NO_TIME_FILTER
     if search_config is not None and "search_time_range" in search_config.model_extra:
-        search_time_range = search_config.model_extra.get("search_time_range")
+        search_time_range = _coerce_seconds(search_config.model_extra.get("search_time_range"), "search_time_range")
 
     fetch_config = get_app_config().get_tool_config("web_fetch")
-    fetch_time = -1
+    fetch_time = _NO_TIME_FILTER
     if fetch_config is not None and "fetch_time" in fetch_config.model_extra:
-        fetch_time = fetch_config.model_extra.get("fetch_time")
-    fetch_timeout = -1
+        fetch_time = _coerce_seconds(fetch_config.model_extra.get("fetch_time"), "fetch_time")
+    fetch_timeout = _NO_TIME_FILTER
     if fetch_config is not None and "timeout" in fetch_config.model_extra:
-        fetch_timeout = fetch_config.model_extra.get("timeout")
-    navigation_timeout = -1
+        fetch_timeout = _coerce_seconds(fetch_config.model_extra.get("timeout"), "timeout")
+    navigation_timeout = _NO_TIME_FILTER
     if fetch_config is not None and "navigation_timeout" in fetch_config.model_extra:
-        navigation_timeout = fetch_config.model_extra.get("navigation_timeout")
+        navigation_timeout = _coerce_seconds(fetch_config.model_extra.get("navigation_timeout"), "navigation_timeout")
 
     image_search_config = get_app_config().get_tool_config("image_search")
-    image_search_time_range = -1
+    image_search_time_range = _NO_TIME_FILTER
     if image_search_config is not None and "image_search_time_range" in image_search_config.model_extra:
-        image_search_time_range = image_search_config.model_extra.get("image_search_time_range")
+        image_search_time_range = _coerce_seconds(image_search_config.model_extra.get("image_search_time_range"), "image_search_time_range")
     image_size = "i"
     if image_search_config is not None and "image_size" in image_search_config.model_extra:
         image_size = image_search_config.model_extra.get("image_size")
diff --git a/backend/tests/test_infoquest_config_timeout_coercion.py b/backend/tests/test_infoquest_config_timeout_coercion.py
new file mode 100644
index 0000000000..be662d3c07
--- /dev/null
+++ b/backend/tests/test_infoquest_config_timeout_coercion.py
@@ -0,0 +1,162 @@
+"""InfoQuest reads its crawl timeouts straight out of ``config.yaml``.
+
+``config.example.yaml`` documents ``timeout``, ``fetch_time`` and ``navigation_timeout``
+as seconds (with -1 to disable), and a ``$VAR`` reference in the config is substituted
+verbatim from the environment, so the value the tool receives can be a string. The
+client then compares those values with ``0``, which raises for anything but a number and
+takes the whole ``web_fetch`` / ``web_search`` call down with it.
+"""
+
+from unittest.mock import AsyncMock, MagicMock
+
+import httpx
+import pytest
+
+from deerflow.community.infoquest import tools
+
+_URL = "https://example.com"
+_FETCH_PAYLOAD = {"reader_result": "<p>Content</p>"}
+_SEARCH_PAYLOAD = {"search_result": {"results": []}}
+
+
+def _app_config(web_search=None, web_fetch=None, image_search=None):
+    """One get_app_config() double whose tool sections are read in order.
+
+    The tool calls get_app_config() once per section, so the same double must be
+    returned every time or its read queue restarts and the wrong section is served.
+    """
+    config = MagicMock()
+    config.get_tool_config.side_effect = [
+        MagicMock(model_extra=web_search or {}),
+        MagicMock(model_extra=web_fetch or {}),
+        MagicMock(model_extra=image_search or {}),
+    ]
+    return config
+
+
+def _mock_transport(monkeypatch, payload):
+    client = MagicMock()
+    client.__aenter__.return_value = client
+    client.__aexit__.return_value = None
+    client.post = AsyncMock(
+        return_value=httpx.Response(
+            200,
+            json=payload,
+            request=httpx.Request("POST", "https://search.infoquest.bytepluses.com"),
+        )
+    )
+    cls = MagicMock()
+    cls.return_value = client
+    monkeypatch.setattr("deerflow.community.infoquest.infoquest_client.httpx.AsyncClient", cls)
+    monkeypatch.setenv("INFOQUEST_API_KEY", "test-placeholder")
+    return client
+
+
+def _client_from_config(monkeypatch, **extras):
+    config = _app_config(**extras)
+    monkeypatch.setattr(tools, "get_app_config", lambda: config)
+    return tools._get_infoquest_client()
+
+
+@pytest.mark.parametrize(
+    ("configured", "expected"),
+    [
+        ("10", 10),
+        (" 10 ", 10),
+        ("-1", -1),
+        (10, 10),
+        (10.0, 10),
+        ("", -1),
+        ("off", -1),
+        (2.5, -1),
+        (True, -1),
+        (None, -1),
+        ({"seconds": 10}, -1),
+    ],
+)
+def test_timeouts_reach_the_client_as_integers(monkeypatch, configured, expected):
+    client = _client_from_config(monkeypatch, web_fetch={"timeout": configured})
+
+    assert client.fetch_timeout == expected
+    assert isinstance(client.fetch_timeout, int)
+
+
+def test_configured_numbers_keep_their_meaning(monkeypatch):
+    """The shapes that already work must not change."""
+    client = _client_from_config(
+        monkeypatch,
+        web_search={"search_time_range": 24},
+        web_fetch={"timeout": 10, "fetch_time": 5, "navigation_timeout": 30},
+        image_search={"image_search_time_range": 7, "image_size": "l"},
+    )
+
+    assert (client.search_time_range, client.image_search_time_range) == (24, 7)
+    assert (client.fetch_timeout, client.fetch_time, client.fetch_navigation_timeout) == (10, 5, 30)
+
+
+@pytest.mark.parametrize(
+    ("configured", "expected"),
+    [
+        ("10", 10),
+        ("", -1),
+        ("off", -1),
+        (None, -1),
+    ],
+)
+def test_string_timeouts_apply_to_every_configured_option(monkeypatch, configured, expected):
+    client = _client_from_config(
+        monkeypatch,
+        web_search={"search_time_range": configured},
+        web_fetch={"timeout": configured, "fetch_time": configured, "navigation_timeout": configured},
+        image_search={"image_search_time_range": configured},
+    )
+
+    assert client.search_time_range == expected
+    assert client.fetch_timeout == expected
+    assert client.fetch_time == expected
+    assert client.fetch_navigation_timeout == expected
+    assert client.image_search_time_range == expected
+
+
+@pytest.mark.anyio
+async def test_env_string_timeout_reaches_the_crawl_request_as_a_number(monkeypatch):
+    """``timeout: $FETCH_TIMEOUT`` is documented, and an outbound crawl must carry 10."""
+    client = _client_from_config(
+        monkeypatch,
+        web_fetch={"timeout": "10", "navigation_timeout": "30", "fetch_time": "5"},
+    )
+    transport = _mock_transport(monkeypatch, _FETCH_PAYLOAD)
+
+    assert await client.fetch(_URL) == "<p>Content</p>"
+
+    sent = transport.post.call_args.kwargs["json"]
+    assert sent["timeout"] == 10
+    assert sent["navi_timeout"] == 30
+    assert sent["fetch_time"] == 5
+
+
+@pytest.mark.anyio
+async def test_env_string_time_range_reaches_the_search_request_as_a_number(monkeypatch):
+    client = _client_from_config(monkeypatch, web_search={"search_time_range": "24"})
+    transport = _mock_transport(monkeypatch, _SEARCH_PAYLOAD)
+
+    assert await client.web_search("query") == "[]"
+
+    assert transport.post.call_args.kwargs["json"]["time_range"] == 24
+
+
+@pytest.mark.anyio
+async def test_an_unusable_timeout_disables_the_filter_instead_of_failing_the_tool(monkeypatch, caplog):
+    client = _client_from_config(
+        monkeypatch,
+        web_fetch={"timeout": "", "navigation_timeout": "off"},
+    )
+    transport = _mock_transport(monkeypatch, _FETCH_PAYLOAD)
+
+    assert await client.fetch(_URL) == "<p>Content</p>"
+
+    sent = transport.post.call_args.kwargs["json"]
+    assert "timeout" not in sent
+    assert "navi_timeout" not in sent
+    assert "fetch_time" not in sent
+    assert "Invalid InfoQuest" in caplog.text