diff --git a/src/config.py b/src/config.py
index fb0da3e..6f547fa 100644
--- a/src/config.py
+++ b/src/config.py
@@ -34,7 +34,7 @@
 PORT = int(os.getenv("AGENTCHATBUS_PORT", config_data.get("PORT", "39765")))
 
 # Agent heartbeat timeout (seconds). Agents missing this window are marked offline.
-AGENT_HEARTBEAT_TIMEOUT = int(os.getenv("AGENTCHATBUS_HEARTBEAT_TIMEOUT", config_data.get("AGENT_HEARTBEAT_TIMEOUT", "30")))
+AGENT_HEARTBEAT_TIMEOUT = int(os.getenv("AGENTCHATBUS_HEARTBEAT_TIMEOUT", config_data.get("AGENT_HEARTBEAT_TIMEOUT", "60")))
 
 # SSE long-poll timeout for msg.wait (seconds)
 MSG_WAIT_TIMEOUT = int(os.getenv("AGENTCHATBUS_WAIT_TIMEOUT", config_data.get("MSG_WAIT_TIMEOUT", "300")))
diff --git a/src/tools/dispatch.py b/src/tools/dispatch.py
index 68e8cd7..1b08754 100644
--- a/src/tools/dispatch.py
+++ b/src/tools/dispatch.py
@@ -1122,8 +1122,10 @@ async def handle_msg_wait(db, arguments: dict[str, Any]) -> list[types.Content]:
     )
     # ─────────────────────────────────────────────────────────────────────────
 
-    # Refresh every 20 seconds to stay online during long-poll waits.
-    HEARTBEAT_INTERVAL = 20.0
+    # Refresh every 40 seconds to stay online during long-poll waits.
+    # LLM-based agents regularly take >20s to respond; 20s was too aggressive
+    # and caused unnecessary heartbeat DB writes. Paired with AGENT_HEARTBEAT_TIMEOUT=60s.
+    HEARTBEAT_INTERVAL = 40.0
 
     async def _refresh_heartbeat() -> None:
         if verified_agent:
diff --git a/tests/test_timeout_handling.py b/tests/test_timeout_handling.py
index 56b6dc3..60d666b 100644
--- a/tests/test_timeout_handling.py
+++ b/tests/test_timeout_handling.py
@@ -73,7 +73,7 @@ def custom_showwarning(self, message, category, filename, lineno, file=None, lin
 @pytest.mark.asyncio
 async def test_api_threads_timeout_on_get_db():
     """Test that API returns 503 when get_db() times out."""
-    with patch("asyncio.wait_for") as mock_wait_for:
+    with patch("src.main.asyncio.wait_for") as mock_wait_for:
         # First call to wait_for (get_db) times out
         mock_wait_for.side_effect = asyncio.TimeoutError()
         
@@ -98,7 +98,7 @@ async def mock_wait_for_impl(coro, timeout):
         else:
             raise asyncio.TimeoutError()
 
-    with patch("asyncio.wait_for", side_effect=mock_wait_for_impl):
+    with patch("src.main.asyncio.wait_for", side_effect=mock_wait_for_impl):
         try:
             await api_threads()
             pytest.fail("Expected HTTPException with 503")
@@ -113,7 +113,7 @@ async def test_api_agents_timeout():
     async def mock_wait_for_impl(coro, timeout):
         raise asyncio.TimeoutError()
 
-    with patch("asyncio.wait_for", side_effect=mock_wait_for_impl):
+    with patch("src.main.asyncio.wait_for", side_effect=mock_wait_for_impl):
         try:
             await api_agents()
             pytest.fail("Expected HTTPException with 503")
@@ -129,7 +129,6 @@ async def mock_wait_for_impl(coro, timeout):
 @pytest.mark.asyncio
 async def test_api_threads_success():
     """Test successful thread listing with no timeout."""
-    mock_db = AsyncMock()
     import datetime
     now = datetime.datetime.now()
 
@@ -145,16 +144,12 @@ async def test_api_threads_success():
         )
     ]
 
-    async def mock_wait_for_get_db(coro, timeout):
-        return mock_db
-
-    async def mock_gather(*coros):
-        return (mock_threads, len(mock_threads))
+    mock_db = AsyncMock()
 
-    with patch("asyncio.wait_for", side_effect=mock_wait_for_get_db), \
-         patch("asyncio.gather", side_effect=mock_gather):
-        # Since api_threads is an async function that returns an envelope dict,
-        # we need to test the actual return value
+    with patch("src.main.get_db", return_value=mock_db), \
+         patch("src.main.crud.thread_list", new=AsyncMock(return_value=mock_threads)), \
+         patch("src.main.crud.thread_count", new=AsyncMock(return_value=len(mock_threads))), \
+         patch("src.main.crud.threads_agents_map", new=AsyncMock(return_value={})):
         result = await api_threads()
 
         # Verify result is an envelope dict with expected structure (UP-20)
@@ -195,7 +190,7 @@ async def mock_wait_for_impl(coro, timeout):
         # Return mock_agents for agent_list calls
         return mock_agents
 
-    with patch("asyncio.wait_for", side_effect=mock_wait_for_impl):
+    with patch("src.main.asyncio.wait_for", side_effect=mock_wait_for_impl):
         result = await api_agents()
 
         assert isinstance(result, list)