diff --git a/gvm/protocols/gmp/_gmpnext.py b/gvm/protocols/gmp/_gmpnext.py
index 8ce40027..e9a1ccd3 100644
--- a/gvm/protocols/gmp/_gmpnext.py
+++ b/gvm/protocols/gmp/_gmpnext.py
@@ -218,6 +218,7 @@ def create_agent_group(
         agent_ids: list[str],
         scheduler_cron_time: str,
         *,
+        max_delay_seconds: int | None = None,
         comment: str | None = None,
     ) -> T:
         """Create a new agent group.
@@ -226,6 +227,7 @@ def create_agent_group(
             name: Name of the new agent group.
             agent_ids: List of agent UUIDs to include in the group (required).
             scheduler_cron_time: Scheduler cron to use.
+            max_delay_seconds: Max delay seconds to use.
             comment: Optional comment for the group.
 
         Raises:
@@ -237,6 +239,7 @@ def create_agent_group(
                 comment=comment,
                 agent_ids=agent_ids,
                 scheduler_cron_time=scheduler_cron_time,
+                max_delay_seconds=max_delay_seconds,
             )
         )
 
@@ -248,6 +251,7 @@ def modify_agent_group(
         name: str | None = None,
         comment: str | None = None,
         agent_ids: list[str] | None = None,
+        max_delay_seconds: int | None = None,
     ) -> T:
         """Modify an existing agent group.
 
@@ -257,6 +261,7 @@ def modify_agent_group(
             scheduler_cron_time: Scheduler cron to use.
             comment: Optional comment for the group.
             agent_ids: Optional list of agent UUIDs to set for the group.
+            max_delay_seconds: Optional maximum delay for agent groups.
 
         Raises:
             RequiredArgument: If agent_group_id is not provided.
@@ -268,6 +273,7 @@ def modify_agent_group(
                 comment=comment,
                 agent_ids=agent_ids,
                 scheduler_cron_time=scheduler_cron_time,
+                max_delay_seconds=max_delay_seconds,
             )
         )
 
diff --git a/gvm/protocols/gmp/requests/next/_agent_groups.py b/gvm/protocols/gmp/requests/next/_agent_groups.py
index c817364e..fb9eca5b 100644
--- a/gvm/protocols/gmp/requests/next/_agent_groups.py
+++ b/gvm/protocols/gmp/requests/next/_agent_groups.py
@@ -18,6 +18,7 @@ def create_agent_group(
         agent_ids: list[str],
         scheduler_cron_time: str,
         *,
+        max_delay_seconds: int | None = None,
         comment: str | None = None,
     ) -> Request:
         """Create a new agent group.
@@ -26,6 +27,7 @@ def create_agent_group(
             name: Name of the new agent group.
             agent_ids: List of agent UUIDs to include in the group (required).
             scheduler_cron_time: Cron-like time to schedule new agent groups (required).
+            max_delay_seconds: Max delay seconds to schedule the new agent group (optional).
             comment: Optional comment for the group.
 
         Raises:
@@ -50,6 +52,9 @@ def create_agent_group(
         cmd.add_element("name", name)
         cmd.add_element("scheduler_cron_time", scheduler_cron_time)
 
+        if max_delay_seconds is not None:
+            cmd.add_element("max_delay_seconds", str(max_delay_seconds))
+
         if comment:
             cmd.add_element("comment", comment)
 
@@ -89,6 +94,7 @@ def modify_agent_group(
         name: str | None = None,
         comment: str | None = None,
         agent_ids: list[str] | None = None,
+        max_delay_seconds: int | None = None,
     ) -> Request:
         """Modify an existing agent group.
 
@@ -98,6 +104,7 @@ def modify_agent_group(
             name: Optional new name for the group.
             comment: Optional comment for the group.
             agent_ids: Optional list of agent UUIDs to set for the group.
+            max_delay_seconds: Max delay seconds to schedule the new agent group.
 
         Raises:
             RequiredArgument: If agent_group_id is not provided.
@@ -127,6 +134,8 @@ def modify_agent_group(
             agents_element = cmd.add_element("agents")
             for agent_id in agent_ids:
                 agents_element.add_element("agent", attrs={"id": agent_id})
+        if max_delay_seconds is not None:
+            cmd.add_element("max_delay_seconds", str(max_delay_seconds))
 
         return cmd
 
diff --git a/gvm/protocols/gmp/requests/next/_agents.py b/gvm/protocols/gmp/requests/next/_agents.py
index e0571567..c8434a76 100644
--- a/gvm/protocols/gmp/requests/next/_agents.py
+++ b/gvm/protocols/gmp/requests/next/_agents.py
@@ -73,20 +73,40 @@ def valid_value(d: Mapping[str, Any], key: str, path: str) -> Any:
         valid_value(se, "indexer_dir_depth", "agent_script_executor.")
 
         sched = se.get("scheduler_cron_time")
-        if isinstance(sched, str):
-            items = [sched]
-        elif isinstance(sched, Sequence) and not isinstance(
-            sched, (str, bytes)
+
+        if (
+            not isinstance(sched, Sequence)
+            or isinstance(sched, (str, bytes))
+            or not sched
         ):
-            items = [str(x) for x in sched]
-        else:
-            items = []
-        if not items or any(not str(x).strip() for x in items):
             raise RequiredArgument(
                 function=caller,
                 argument="config.agent_script_executor.scheduler_cron_time",
             )
 
+        for item in sched:
+            if not isinstance(item, Mapping):
+                raise InvalidArgumentType(
+                    function=caller,
+                    argument="config.agent_script_executor.scheduler_cron_time",
+                    arg_type="Mapping",
+                )
+
+            cron = item.get("cron")
+            max_delay_seconds = item.get("max_delay_seconds")
+
+            if not isinstance(cron, str) or not cron.strip():
+                raise RequiredArgument(
+                    function=caller,
+                    argument="config.agent_script_executor.scheduler_cron_time.cron",
+                )
+
+            if type(max_delay_seconds) is not int or max_delay_seconds < 0:
+                raise InvalidArgumentType(
+                    function=caller,
+                    argument="config.agent_script_executor.scheduler_cron_time.max_delay_seconds",
+                    arg_type="non-negative integer",
+                )
         # heartbeat
         hb = valid_map(config, "heartbeat", "")
         valid_value(hb, "interval_in_seconds", "heartbeat.")
@@ -162,7 +182,12 @@ def _append_agent_config(
                     "bulk_size": 2,
                     "bulk_throttle_time_in_ms": 300,
                     "indexer_dir_depth": 100,
-                    "scheduler_cron_time": ["0 */12 * * *"],
+                    "scheduler_cron_time": [
+                        {
+                            "cron": "0 */12 * * *",
+                            "max_delay_seconds": 30,
+                        },
+                    ],
                 },
                 "heartbeat": {
                     "interval_in_seconds": 300,
@@ -212,18 +237,21 @@ def _append_agent_config(
             xml_se, "indexer_dir_depth", se.get("indexer_dir_depth")
         )
         sched = se.get("scheduler_cron_time")
-        if isinstance(sched, str):
-            sched_items = [sched]
-        else:
-            sched_items = list(sched or [])
 
-        if sched_items:
+        if sched:
             xml_sched = xml_se.add_element(
                 "scheduler_cron_time",
                 attrs={"is_list": "1"},
             )
-            for item in sched_items:
-                xml_sched.add_element("item", str(item))
+
+            for item in sched:
+                xml_item = xml_sched.add_element("item")
+                cls._add_element(xml_item, "cron", item["cron"])
+                cls._add_element(
+                    xml_item,
+                    "max_delay_seconds",
+                    item["max_delay_seconds"],
+                )
 
         # heartbeat
         hb = config["heartbeat"]
@@ -311,7 +339,12 @@ def modify_agents(
                       "bulk_size": 2,
                       "bulk_throttle_time_in_ms": 300,
                       "indexer_dir_depth": 100,
-                      "scheduler_cron_time": ["0 */12 * * *"],  # str or list[str]
+                      "scheduler_cron_time": [
+                          {
+                              "cron": "0 */12 * * *",
+                              "max_delay_seconds": 30,
+                          },
+                      ],
                   },
                   "heartbeat": {
                       "interval_in_seconds": 300,
@@ -393,7 +426,16 @@ def modify_agent_control_scan_config(
                             "bulk_size": 2,
                             "bulk_throttle_time_in_ms": 300,
                             "indexer_dir_depth": 100,
-                            "scheduler_cron_time": ["0 */12 * * *"],
+                            "scheduler_cron_time": [
+                                {
+                                    "cron": "0 */12 * * *",
+                                    "max_delay_seconds": 30,
+                                },
+                                {
+                                    "cron": "0 23 * * *",
+                                    "max_delay_seconds": 60,
+                                },
+                            ],
                         },
                         "heartbeat": {
                             "interval_in_seconds": 300,
@@ -410,6 +452,7 @@ def modify_agent_control_scan_config(
                 function=cls.modify_agent_control_scan_config.__name__,
                 argument="agent_control_id",
             )
+
         if not config_defaults:
             raise RequiredArgument(
                 function=cls.modify_agent_control_scan_config.__name__,
diff --git a/tests/protocols/gmpnext/entities/agent_groups/test_create_agent_group.py b/tests/protocols/gmpnext/entities/agent_groups/test_create_agent_group.py
index 80bf2c74..95a0291a 100644
--- a/tests/protocols/gmpnext/entities/agent_groups/test_create_agent_group.py
+++ b/tests/protocols/gmpnext/entities/agent_groups/test_create_agent_group.py
@@ -12,12 +12,14 @@ def test_create_agent_group(self):
             agent_ids=["agent-1", "agent-2"],
             comment="Sample comment",
             scheduler_cron_time="0 */5 * * *",
+            max_delay_seconds=30,
         )
 
         self.connection.send.has_been_called_with(
             b"<create_agent_group>"
             b"<name>ExampleGroup</name>"
             b"<scheduler_cron_time>0 */5 * * *</scheduler_cron_time>"
+            b"<max_delay_seconds>30</max_delay_seconds>"
             b"<comment>Sample comment</comment>"
             b'<agents><agent id="agent-1"/><agent id="agent-2"/></agents>'
             b"</create_agent_group>"
@@ -57,3 +59,35 @@ def test_create_agent_group_without_comment(self):
             b'<agents><agent id="a1"/><agent id="a2"/></agents>'
             b"</create_agent_group>"
         )
+
+    def test_create_agent_group_with_zero_max_delay(self):
+        self.gmp.create_agent_group(
+            name="GroupX",
+            agent_ids=["a1"],
+            scheduler_cron_time="0 */5 * * *",
+            max_delay_seconds=0,
+        )
+
+        self.connection.send.has_been_called_with(
+            b"<create_agent_group>"
+            b"<name>GroupX</name>"
+            b"<scheduler_cron_time>0 */5 * * *</scheduler_cron_time>"
+            b"<max_delay_seconds>0</max_delay_seconds>"
+            b'<agents><agent id="a1"/></agents>'
+            b"</create_agent_group>"
+        )
+
+    def test_create_agent_group_without_max_delay(self):
+        self.gmp.create_agent_group(
+            name="GroupX",
+            agent_ids=["a1"],
+            scheduler_cron_time="0 */5 * * *",
+        )
+
+        self.connection.send.has_been_called_with(
+            b"<create_agent_group>"
+            b"<name>GroupX</name>"
+            b"<scheduler_cron_time>0 */5 * * *</scheduler_cron_time>"
+            b'<agents><agent id="a1"/></agents>'
+            b"</create_agent_group>"
+        )
diff --git a/tests/protocols/gmpnext/entities/agent_groups/test_modify_agent_group.py b/tests/protocols/gmpnext/entities/agent_groups/test_modify_agent_group.py
index c7f809ea..e179ba14 100644
--- a/tests/protocols/gmpnext/entities/agent_groups/test_modify_agent_group.py
+++ b/tests/protocols/gmpnext/entities/agent_groups/test_modify_agent_group.py
@@ -12,6 +12,7 @@ def test_modify_agent_group(self):
             name="NewName",
             comment="Updated comment",
             scheduler_cron_time="0 */5 * * *",
+            max_delay_seconds=30,
             agent_ids=["agent-1", "agent-2"],
         )
 
@@ -21,6 +22,7 @@ def test_modify_agent_group(self):
             b"<name>NewName</name>"
             b"<comment>Updated comment</comment>"
             b'<agents><agent id="agent-1"/><agent id="agent-2"/></agents>'
+            b"<max_delay_seconds>30</max_delay_seconds>"
             b"</modify_agent_group>"
         )
 
@@ -83,3 +85,29 @@ def test_modify_agent_group_without_agent_ids(self):
             b"<comment>Updated comment</comment>"
             b"</modify_agent_group>"
         )
+
+    def test_modify_agent_group_with_zero_max_delay(self):
+        self.gmp.modify_agent_group(
+            agent_group_id="group-1",
+            scheduler_cron_time="0 */5 * * *",
+            max_delay_seconds=0,
+        )
+
+        self.connection.send.has_been_called_with(
+            b'<modify_agent_group agent_group_id="group-1">'
+            b"<scheduler_cron_time>0 */5 * * *</scheduler_cron_time>"
+            b"<max_delay_seconds>0</max_delay_seconds>"
+            b"</modify_agent_group>"
+        )
+
+    def test_modify_agent_group_without_max_delay(self):
+        self.gmp.modify_agent_group(
+            agent_group_id="group-1",
+            scheduler_cron_time="0 */5 * * *",
+        )
+
+        self.connection.send.has_been_called_with(
+            b'<modify_agent_group agent_group_id="group-1">'
+            b"<scheduler_cron_time>0 */5 * * *</scheduler_cron_time>"
+            b"</modify_agent_group>"
+        )
diff --git a/tests/protocols/gmpnext/entities/agents/test_modify_agent_controller_scan_config.py b/tests/protocols/gmpnext/entities/agents/test_modify_agent_controller_scan_config.py
index 5e293bae..0d9d3b7a 100644
--- a/tests/protocols/gmpnext/entities/agents/test_modify_agent_controller_scan_config.py
+++ b/tests/protocols/gmpnext/entities/agents/test_modify_agent_controller_scan_config.py
@@ -21,8 +21,8 @@ def test_modify_agent_control_scan_config_full(self):
                     "bulk_throttle_time_in_ms": 100,
                     "indexer_dir_depth": 10,
                     "scheduler_cron_time": [
-                        "0 23 * * *",
-                        "0 22 * * *",
+                        {"cron": "0 23 * * *", "max_delay_seconds": 30},
+                        {"cron": "0 22 * * *", "max_delay_seconds": 60},
                     ],
                 },
                 "heartbeat": {
@@ -56,8 +56,10 @@ def test_modify_agent_control_scan_config_full(self):
             b"<bulk_throttle_time_in_ms>100</bulk_throttle_time_in_ms>"
             b"<indexer_dir_depth>10</indexer_dir_depth>"
             b'<scheduler_cron_time is_list="1">'
-            b"<item>0 23 * * *</item>"
-            b"<item>0 22 * * *</item>"
+            b"<item><cron>0 23 * * *</cron>"
+            b"<max_delay_seconds>30</max_delay_seconds></item>"
+            b"<item><cron>0 22 * * *</cron>"
+            b"<max_delay_seconds>60</max_delay_seconds></item>"
             b"</scheduler_cron_time>"
             b"</agent_script_executor>"
             b"<heartbeat>"
@@ -72,32 +74,85 @@ def test_modify_agent_control_scan_config_full(self):
             b"</modify_agent_control_scan_config>"
         )
 
+    def test_modify_agent_control_scan_config_zero_max_delay(self):
+        config = {
+            "agent_defaults": {
+                "agent_control": {
+                    "retry": {
+                        "attempts": 6,
+                        "delay_in_seconds": 60,
+                        "max_jitter_in_seconds": 10,
+                    }
+                },
+                "agent_script_executor": {
+                    "bulk_size": 1,
+                    "bulk_throttle_time_in_ms": 100,
+                    "indexer_dir_depth": 10,
+                    "scheduler_cron_time": [
+                        {"cron": "0 23 * * *", "max_delay_seconds": 0},
+                    ],
+                },
+                "heartbeat": {
+                    "interval_in_seconds": 600,
+                    "miss_until_inactive": 1,
+                },
+            },
+            "agent_control_defaults": {"update_to_latest": True},
+        }
+
+        self.gmp.modify_agent_control_scan_config(
+            "3b4be213-281f-49ee-b457-5a5f34f71510",
+            config=config,
+        )
+
+        self.connection.send.has_been_called_with(
+            b'<modify_agent_control_scan_config agent_control_id="3b4be213-281f-49ee-b457-5a5f34f71510">'
+            b"<config_defaults><agent_defaults><agent_control><retry>"
+            b"<attempts>6</attempts>"
+            b"<delay_in_seconds>60</delay_in_seconds>"
+            b"<max_jitter_in_seconds>10</max_jitter_in_seconds>"
+            b"</retry></agent_control><agent_script_executor>"
+            b"<bulk_size>1</bulk_size>"
+            b"<bulk_throttle_time_in_ms>100</bulk_throttle_time_in_ms>"
+            b"<indexer_dir_depth>10</indexer_dir_depth>"
+            b'<scheduler_cron_time is_list="1">'
+            b"<item><cron>0 23 * * *</cron>"
+            b"<max_delay_seconds>0</max_delay_seconds></item>"
+            b"</scheduler_cron_time></agent_script_executor>"
+            b"<heartbeat><interval_in_seconds>600</interval_in_seconds>"
+            b"<miss_until_inactive>1</miss_until_inactive></heartbeat>"
+            b"</agent_defaults><agent_control_defaults>"
+            b"<update_to_latest>1</update_to_latest>"
+            b"</agent_control_defaults></config_defaults>"
+            b"</modify_agent_control_scan_config>"
+        )
+
     def test_modify_agent_control_scan_config_with_missing_element_raises(self):
         cfg = {
-            "config_defaults": {
-                "agent_defaults": {
-                    "agent_control": {
-                        "retry": {
-                            "attempts": 6,
-                            "delay_in_seconds": 60,
-                            # max_jitter_in_seconds is missing
-                        }
-                    },
-                    "agent_script_executor": {
-                        "bulk_size": 2,
-                        "bulk_throttle_time_in_ms": 300,
-                        "indexer_dir_depth": 100,
-                        "scheduler_cron_time": ["0 */12 * * *"],
-                    },
-                    "heartbeat": {
-                        "interval_in_seconds": 300,
-                        "miss_until_inactive": 1,
-                    },
+            "agent_defaults": {
+                "agent_control": {
+                    "retry": {
+                        "attempts": 6,
+                        "delay_in_seconds": 60,
+                        # max_jitter_in_seconds is missing
+                    }
+                },
+                "agent_script_executor": {
+                    "bulk_size": 2,
+                    "bulk_throttle_time_in_ms": 300,
+                    "indexer_dir_depth": 100,
+                    "scheduler_cron_time": [
+                        {"cron": "0 */12 * * *", "max_delay_seconds": 30}
+                    ],
                 },
-                "agent_control_defaults": {
-                    "update_to_latest": True,
+                "heartbeat": {
+                    "interval_in_seconds": 300,
+                    "miss_until_inactive": 1,
                 },
-            }
+            },
+            "agent_control_defaults": {
+                "update_to_latest": True,
+            },
         }
 
         with self.assertRaises(RequiredArgument):
@@ -111,30 +166,33 @@ def test_modify_agent_control_scan_config_missing_id_raises(self):
             self.gmp.modify_agent_control_scan_config(
                 "",  # missing id
                 config={
-                    "config_defaults": {
-                        "agent_defaults": {
-                            "agent_control": {
-                                "retry": {
-                                    "attempts": 6,
-                                    "delay_in_seconds": 60,
-                                    "max_jitter_in_seconds": 10,
+                    "agent_defaults": {
+                        "agent_control": {
+                            "retry": {
+                                "attempts": 6,
+                                "delay_in_seconds": 60,
+                                "max_jitter_in_seconds": 10,
+                            }
+                        },
+                        "agent_script_executor": {
+                            "bulk_size": 2,
+                            "bulk_throttle_time_in_ms": 300,
+                            "indexer_dir_depth": 100,
+                            "scheduler_cron_time": [
+                                {
+                                    "cron": "0 */12 * * *",
+                                    "max_delay_seconds": 30,
                                 }
-                            },
-                            "agent_script_executor": {
-                                "bulk_size": 2,
-                                "bulk_throttle_time_in_ms": 300,
-                                "indexer_dir_depth": 100,
-                                "scheduler_cron_time": ["0 */12 * * *"],
-                            },
-                            "heartbeat": {
-                                "interval_in_seconds": 300,
-                                "miss_until_inactive": 1,
-                            },
+                            ],
                         },
-                        "agent_control_defaults": {
-                            "update_to_latest": True,
+                        "heartbeat": {
+                            "interval_in_seconds": 300,
+                            "miss_until_inactive": 1,
                         },
-                    }
+                    },
+                    "agent_control_defaults": {
+                        "update_to_latest": True,
+                    },
                 },
             )
 
@@ -155,24 +213,24 @@ def test_modify_agent_control_scan_config_agent_control_not_mapping_raises(
         self,
     ):
         cfg = {
-            "config_defaults": {
-                "agent_defaults": {
-                    "agent_control": "oops-not-a-mapping",
-                    "agent_script_executor": {
-                        "bulk_size": 2,
-                        "bulk_throttle_time_in_ms": 300,
-                        "indexer_dir_depth": 100,
-                        "scheduler_cron_time": ["0 */12 * * *"],
-                    },
-                    "heartbeat": {
-                        "interval_in_seconds": 300,
-                        "miss_until_inactive": 1,
-                    },
+            "agent_defaults": {
+                "agent_control": "oops-not-a-mapping",
+                "agent_script_executor": {
+                    "bulk_size": 2,
+                    "bulk_throttle_time_in_ms": 300,
+                    "indexer_dir_depth": 100,
+                    "scheduler_cron_time": [
+                        {"cron": "0 */12 * * *", "max_delay_seconds": 30}
+                    ],
                 },
-                "agent_control_defaults": {
-                    "update_to_latest": True,
+                "heartbeat": {
+                    "interval_in_seconds": 300,
+                    "miss_until_inactive": 1,
                 },
-            }
+            },
+            "agent_control_defaults": {
+                "update_to_latest": True,
+            },
         }
         with self.assertRaises(RequiredArgument):
             self.gmp.modify_agent_control_scan_config(
@@ -181,30 +239,28 @@ def test_modify_agent_control_scan_config_agent_control_not_mapping_raises(
 
     def test_modify_agent_control_scan_config_scheduler_empty_list_raises(self):
         cfg = {
-            "config_defaults": {
-                "agent_defaults": {
-                    "agent_control": {
-                        "retry": {
-                            "attempts": 6,
-                            "delay_in_seconds": 60,
-                            "max_jitter_in_seconds": 10,
-                        }
-                    },
-                    "agent_script_executor": {
-                        "bulk_size": 2,
-                        "bulk_throttle_time_in_ms": 300,
-                        "indexer_dir_depth": 100,
-                        "scheduler_cron_time": [],
-                    },
-                    "heartbeat": {
-                        "interval_in_seconds": 300,
-                        "miss_until_inactive": 1,
-                    },
+            "agent_defaults": {
+                "agent_control": {
+                    "retry": {
+                        "attempts": 6,
+                        "delay_in_seconds": 60,
+                        "max_jitter_in_seconds": 10,
+                    }
                 },
-                "agent_control_defaults": {
-                    "update_to_latest": True,
+                "agent_script_executor": {
+                    "bulk_size": 2,
+                    "bulk_throttle_time_in_ms": 300,
+                    "indexer_dir_depth": 100,
+                    "scheduler_cron_time": [],
                 },
-            }
+                "heartbeat": {
+                    "interval_in_seconds": 300,
+                    "miss_until_inactive": 1,
+                },
+            },
+            "agent_control_defaults": {
+                "update_to_latest": True,
+            },
         }
         with self.assertRaises(RequiredArgument):
             self.gmp.modify_agent_control_scan_config(
@@ -215,30 +271,31 @@ def test_modify_agent_control_scan_config_scheduler_with_empty_item_raises(
         self,
     ):
         cfg = {
-            "config_defaults": {
-                "agent_defaults": {
-                    "agent_control": {
-                        "retry": {
-                            "attempts": 6,
-                            "delay_in_seconds": 60,
-                            "max_jitter_in_seconds": 10,
-                        }
-                    },
-                    "agent_script_executor": {
-                        "bulk_size": 2,
-                        "bulk_throttle_time_in_ms": 300,
-                        "indexer_dir_depth": 100,
-                        "scheduler_cron_time": ["", "   "],
-                    },
-                    "heartbeat": {
-                        "interval_in_seconds": 300,
-                        "miss_until_inactive": 1,
-                    },
+            "agent_defaults": {
+                "agent_control": {
+                    "retry": {
+                        "attempts": 6,
+                        "delay_in_seconds": 60,
+                        "max_jitter_in_seconds": 10,
+                    }
                 },
-                "agent_control_defaults": {
-                    "update_to_latest": True,
+                "agent_script_executor": {
+                    "bulk_size": 2,
+                    "bulk_throttle_time_in_ms": 300,
+                    "indexer_dir_depth": 100,
+                    "scheduler_cron_time": [
+                        {"cron": "", "max_delay_seconds": 30},
+                        {"cron": "   ", "max_delay_seconds": 30},
+                    ],
+                },
+                "heartbeat": {
+                    "interval_in_seconds": 300,
+                    "miss_until_inactive": 1,
                 },
-            }
+            },
+            "agent_control_defaults": {
+                "update_to_latest": True,
+            },
         }
         with self.assertRaises(RequiredArgument):
             self.gmp.modify_agent_control_scan_config(
@@ -249,24 +306,24 @@ def test_modify_agent_control_scan_config_missing_agent_control_raises(
         self,
     ):
         cfg = {
-            "config_defaults": {
-                "agent_defaults": {
-                    # "agent_control": missing
-                    "agent_script_executor": {
-                        "bulk_size": 2,
-                        "bulk_throttle_time_in_ms": 300,
-                        "indexer_dir_depth": 100,
-                        "scheduler_cron_time": ["0 */12 * * *"],
-                    },
-                    "heartbeat": {
-                        "interval_in_seconds": 300,
-                        "miss_until_inactive": 1,
-                    },
+            "agent_defaults": {
+                # "agent_control": missing
+                "agent_script_executor": {
+                    "bulk_size": 2,
+                    "bulk_throttle_time_in_ms": 300,
+                    "indexer_dir_depth": 100,
+                    "scheduler_cron_time": [
+                        {"cron": "0 */12 * * *", "max_delay_seconds": 30}
+                    ],
                 },
-                "agent_control_defaults": {
-                    "update_to_latest": True,
+                "heartbeat": {
+                    "interval_in_seconds": 300,
+                    "miss_until_inactive": 1,
                 },
-            }
+            },
+            "agent_control_defaults": {
+                "update_to_latest": True,
+            },
         }
         with self.assertRaises(RequiredArgument):
             self.gmp.modify_agent_control_scan_config(
@@ -275,26 +332,26 @@ def test_modify_agent_control_scan_config_missing_agent_control_raises(
 
     def test_modify_agent_control_scan_config_missing_retry_block_raises(self):
         cfg = {
-            "config_defaults": {
-                "agent_defaults": {
-                    "agent_control": {
-                        # "retry": {}
-                    },
-                    "agent_script_executor": {
-                        "bulk_size": 2,
-                        "bulk_throttle_time_in_ms": 300,
-                        "indexer_dir_depth": 100,
-                        "scheduler_cron_time": ["0 */12 * * *"],
-                    },
-                    "heartbeat": {
-                        "interval_in_seconds": 300,
-                        "miss_until_inactive": 1,
-                    },
+            "agent_defaults": {
+                "agent_control": {
+                    # "retry": {}
                 },
-                "agent_control_defaults": {
-                    "update_to_latest": True,
+                "agent_script_executor": {
+                    "bulk_size": 2,
+                    "bulk_throttle_time_in_ms": 300,
+                    "indexer_dir_depth": 100,
+                    "scheduler_cron_time": [
+                        {"cron": "0 */12 * * *", "max_delay_seconds": 30}
+                    ],
                 },
-            }
+                "heartbeat": {
+                    "interval_in_seconds": 300,
+                    "miss_until_inactive": 1,
+                },
+            },
+            "agent_control_defaults": {
+                "update_to_latest": True,
+            },
         }
         with self.assertRaises(RequiredArgument):
             self.gmp.modify_agent_control_scan_config(
@@ -305,30 +362,30 @@ def test_modify_agent_control_scan_config_missing_retry_attempts_raises(
         self,
     ):
         cfg = {
-            "config_defaults": {
-                "agent_defaults": {
-                    "agent_control": {
-                        "retry": {
-                            # "attempts": 6,
-                            "delay_in_seconds": 60,
-                            "max_jitter_in_seconds": 10,
-                        }
-                    },
-                    "agent_script_executor": {
-                        "bulk_size": 2,
-                        "bulk_throttle_time_in_ms": 300,
-                        "indexer_dir_depth": 100,
-                        "scheduler_cron_time": ["0 */12 * * *"],
-                    },
-                    "heartbeat": {
-                        "interval_in_seconds": 300,
-                        "miss_until_inactive": 1,
-                    },
+            "agent_defaults": {
+                "agent_control": {
+                    "retry": {
+                        # "attempts": 6,
+                        "delay_in_seconds": 60,
+                        "max_jitter_in_seconds": 10,
+                    }
                 },
-                "agent_control_defaults": {
-                    "update_to_latest": True,
+                "agent_script_executor": {
+                    "bulk_size": 2,
+                    "bulk_throttle_time_in_ms": 300,
+                    "indexer_dir_depth": 100,
+                    "scheduler_cron_time": [
+                        {"cron": "0 */12 * * *", "max_delay_seconds": 30}
+                    ],
+                },
+                "heartbeat": {
+                    "interval_in_seconds": 300,
+                    "miss_until_inactive": 1,
                 },
-            }
+            },
+            "agent_control_defaults": {
+                "update_to_latest": True,
+            },
         }
         with self.assertRaises(RequiredArgument):
             self.gmp.modify_agent_control_scan_config(
@@ -337,30 +394,30 @@ def test_modify_agent_control_scan_config_missing_retry_attempts_raises(
 
     def test_modify_agent_control_scan_config_missing_retry_delay_raises(self):
         cfg = {
-            "config_defaults": {
-                "agent_defaults": {
-                    "agent_control": {
-                        "retry": {
-                            "attempts": 6,
-                            # "delay_in_seconds": 60,
-                            "max_jitter_in_seconds": 10,
-                        }
-                    },
-                    "agent_script_executor": {
-                        "bulk_size": 2,
-                        "bulk_throttle_time_in_ms": 300,
-                        "indexer_dir_depth": 100,
-                        "scheduler_cron_time": ["0 */12 * * *"],
-                    },
-                    "heartbeat": {
-                        "interval_in_seconds": 300,
-                        "miss_until_inactive": 1,
-                    },
+            "agent_defaults": {
+                "agent_control": {
+                    "retry": {
+                        "attempts": 6,
+                        # "delay_in_seconds": 60,
+                        "max_jitter_in_seconds": 10,
+                    }
                 },
-                "agent_control_defaults": {
-                    "update_to_latest": True,
+                "agent_script_executor": {
+                    "bulk_size": 2,
+                    "bulk_throttle_time_in_ms": 300,
+                    "indexer_dir_depth": 100,
+                    "scheduler_cron_time": [
+                        {"cron": "0 */12 * * *", "max_delay_seconds": 30}
+                    ],
                 },
-            }
+                "heartbeat": {
+                    "interval_in_seconds": 300,
+                    "miss_until_inactive": 1,
+                },
+            },
+            "agent_control_defaults": {
+                "update_to_latest": True,
+            },
         }
         with self.assertRaises(RequiredArgument):
             self.gmp.modify_agent_control_scan_config(
@@ -371,30 +428,30 @@ def test_modify_agent_control_scan_config_missing_retry_max_jitter_raises(
         self,
     ):
         cfg = {
-            "config_defaults": {
-                "agent_defaults": {
-                    "agent_control": {
-                        "retry": {
-                            "attempts": 6,
-                            "delay_in_seconds": 60,
-                            # "max_jitter_in_seconds": 10,
-                        }
-                    },
-                    "agent_script_executor": {
-                        "bulk_size": 2,
-                        "bulk_throttle_time_in_ms": 300,
-                        "indexer_dir_depth": 100,
-                        "scheduler_cron_time": ["0 */12 * * *"],
-                    },
-                    "heartbeat": {
-                        "interval_in_seconds": 300,
-                        "miss_until_inactive": 1,
-                    },
+            "agent_defaults": {
+                "agent_control": {
+                    "retry": {
+                        "attempts": 6,
+                        "delay_in_seconds": 60,
+                        # "max_jitter_in_seconds": 10,
+                    }
+                },
+                "agent_script_executor": {
+                    "bulk_size": 2,
+                    "bulk_throttle_time_in_ms": 300,
+                    "indexer_dir_depth": 100,
+                    "scheduler_cron_time": [
+                        {"cron": "0 */12 * * *", "max_delay_seconds": 30}
+                    ],
                 },
-                "agent_control_defaults": {
-                    "update_to_latest": True,
+                "heartbeat": {
+                    "interval_in_seconds": 300,
+                    "miss_until_inactive": 1,
                 },
-            }
+            },
+            "agent_control_defaults": {
+                "update_to_latest": True,
+            },
         }
         with self.assertRaises(RequiredArgument):
             self.gmp.modify_agent_control_scan_config(
@@ -405,25 +462,23 @@ def test_modify_agent_control_scan_config_missing_agent_script_executor_raises(
         self,
     ):
         cfg = {
-            "config_defaults": {
-                "agent_defaults": {
-                    "agent_control": {
-                        "retry": {
-                            "attempts": 6,
-                            "delay_in_seconds": 60,
-                            "max_jitter_in_seconds": 10,
-                        }
-                    },
-                    # "agent_script_executor": missing,
-                    "heartbeat": {
-                        "interval_in_seconds": 300,
-                        "miss_until_inactive": 1,
-                    },
+            "agent_defaults": {
+                "agent_control": {
+                    "retry": {
+                        "attempts": 6,
+                        "delay_in_seconds": 60,
+                        "max_jitter_in_seconds": 10,
+                    }
                 },
-                "agent_control_defaults": {
-                    "update_to_latest": True,
+                # "agent_script_executor": missing,
+                "heartbeat": {
+                    "interval_in_seconds": 300,
+                    "miss_until_inactive": 1,
                 },
-            }
+            },
+            "agent_control_defaults": {
+                "update_to_latest": True,
+            },
         }
         with self.assertRaises(RequiredArgument):
             self.gmp.modify_agent_control_scan_config(
@@ -432,30 +487,30 @@ def test_modify_agent_control_scan_config_missing_agent_script_executor_raises(
 
     def test_modify_agent_control_scan_config_missing_bulk_size_raises(self):
         cfg = {
-            "config_defaults": {
-                "agent_defaults": {
-                    "agent_control": {
-                        "retry": {
-                            "attempts": 6,
-                            "delay_in_seconds": 60,
-                            "max_jitter_in_seconds": 10,
-                        }
-                    },
-                    "agent_script_executor": {
-                        # "bulk_size": 2,
-                        "bulk_throttle_time_in_ms": 300,
-                        "indexer_dir_depth": 100,
-                        "scheduler_cron_time": ["0 */12 * * *"],
-                    },
-                    "heartbeat": {
-                        "interval_in_seconds": 300,
-                        "miss_until_inactive": 1,
-                    },
+            "agent_defaults": {
+                "agent_control": {
+                    "retry": {
+                        "attempts": 6,
+                        "delay_in_seconds": 60,
+                        "max_jitter_in_seconds": 10,
+                    }
                 },
-                "agent_control_defaults": {
-                    "update_to_latest": True,
+                "agent_script_executor": {
+                    # "bulk_size": 2,
+                    "bulk_throttle_time_in_ms": 300,
+                    "indexer_dir_depth": 100,
+                    "scheduler_cron_time": [
+                        {"cron": "0 */12 * * *", "max_delay_seconds": 30}
+                    ],
                 },
-            }
+                "heartbeat": {
+                    "interval_in_seconds": 300,
+                    "miss_until_inactive": 1,
+                },
+            },
+            "agent_control_defaults": {
+                "update_to_latest": True,
+            },
         }
         with self.assertRaises(RequiredArgument):
             self.gmp.modify_agent_control_scan_config(
@@ -466,30 +521,30 @@ def test_modify_agent_control_scan_config_missing_bulk_throttle_time_in_ms_raise
         self,
     ):
         cfg = {
-            "config_defaults": {
-                "agent_defaults": {
-                    "agent_control": {
-                        "retry": {
-                            "attempts": 6,
-                            "delay_in_seconds": 60,
-                            "max_jitter_in_seconds": 10,
-                        }
-                    },
-                    "agent_script_executor": {
-                        "bulk_size": 2,
-                        # "bulk_throttle_time_in_ms": 300,
-                        "indexer_dir_depth": 100,
-                        "scheduler_cron_time": ["0 */12 * * *"],
-                    },
-                    "heartbeat": {
-                        "interval_in_seconds": 300,
-                        "miss_until_inactive": 1,
-                    },
+            "agent_defaults": {
+                "agent_control": {
+                    "retry": {
+                        "attempts": 6,
+                        "delay_in_seconds": 60,
+                        "max_jitter_in_seconds": 10,
+                    }
                 },
-                "agent_control_defaults": {
-                    "update_to_latest": True,
+                "agent_script_executor": {
+                    "bulk_size": 2,
+                    # "bulk_throttle_time_in_ms": 300,
+                    "indexer_dir_depth": 100,
+                    "scheduler_cron_time": [
+                        {"cron": "0 */12 * * *", "max_delay_seconds": 30}
+                    ],
                 },
-            }
+                "heartbeat": {
+                    "interval_in_seconds": 300,
+                    "miss_until_inactive": 1,
+                },
+            },
+            "agent_control_defaults": {
+                "update_to_latest": True,
+            },
         }
         with self.assertRaises(RequiredArgument):
             self.gmp.modify_agent_control_scan_config(
@@ -500,30 +555,30 @@ def test_modify_agent_control_scan_config_missing_indexer_dir_depth_raises(
         self,
     ):
         cfg = {
-            "config_defaults": {
-                "agent_defaults": {
-                    "agent_control": {
-                        "retry": {
-                            "attempts": 6,
-                            "delay_in_seconds": 60,
-                            "max_jitter_in_seconds": 10,
-                        }
-                    },
-                    "agent_script_executor": {
-                        "bulk_size": 2,
-                        "bulk_throttle_time_in_ms": 300,
-                        # "indexer_dir_depth": 100,
-                        "scheduler_cron_time": ["0 */12 * * *"],
-                    },
-                    "heartbeat": {
-                        "interval_in_seconds": 300,
-                        "miss_until_inactive": 1,
-                    },
+            "agent_defaults": {
+                "agent_control": {
+                    "retry": {
+                        "attempts": 6,
+                        "delay_in_seconds": 60,
+                        "max_jitter_in_seconds": 10,
+                    }
                 },
-                "agent_control_defaults": {
-                    "update_to_latest": True,
+                "agent_script_executor": {
+                    "bulk_size": 2,
+                    "bulk_throttle_time_in_ms": 300,
+                    # "indexer_dir_depth": 100,
+                    "scheduler_cron_time": [
+                        {"cron": "0 */12 * * *", "max_delay_seconds": 30}
+                    ],
+                },
+                "heartbeat": {
+                    "interval_in_seconds": 300,
+                    "miss_until_inactive": 1,
                 },
-            }
+            },
+            "agent_control_defaults": {
+                "update_to_latest": True,
+            },
         }
         with self.assertRaises(RequiredArgument):
             self.gmp.modify_agent_control_scan_config(
@@ -534,27 +589,27 @@ def test_modify_agent_control_scan_config_missing_heartbeat_block_raises(
         self,
     ):
         cfg = {
-            "config_defaults": {
-                "agent_defaults": {
-                    "agent_control": {
-                        "retry": {
-                            "attempts": 6,
-                            "delay_in_seconds": 60,
-                            "max_jitter_in_seconds": 10,
-                        }
-                    },
-                    "agent_script_executor": {
-                        "bulk_size": 2,
-                        "bulk_throttle_time_in_ms": 300,
-                        "indexer_dir_depth": 100,
-                        "scheduler_cron_time": ["0 */12 * * *"],
-                    },
-                    # "heartbeat": missing,
+            "agent_defaults": {
+                "agent_control": {
+                    "retry": {
+                        "attempts": 6,
+                        "delay_in_seconds": 60,
+                        "max_jitter_in_seconds": 10,
+                    }
                 },
-                "agent_control_defaults": {
-                    "update_to_latest": True,
+                "agent_script_executor": {
+                    "bulk_size": 2,
+                    "bulk_throttle_time_in_ms": 300,
+                    "indexer_dir_depth": 100,
+                    "scheduler_cron_time": [
+                        {"cron": "0 */12 * * *", "max_delay_seconds": 30}
+                    ],
                 },
-            }
+                # "heartbeat": missing,
+            },
+            "agent_control_defaults": {
+                "update_to_latest": True,
+            },
         }
         with self.assertRaises(RequiredArgument):
             self.gmp.modify_agent_control_scan_config(
@@ -565,30 +620,30 @@ def test_modify_agent_control_scan_config_missing_heartbeat_interval_raises(
         self,
     ):
         cfg = {
-            "config_defaults": {
-                "agent_defaults": {
-                    "agent_control": {
-                        "retry": {
-                            "attempts": 6,
-                            "delay_in_seconds": 60,
-                            "max_jitter_in_seconds": 10,
-                        }
-                    },
-                    "agent_script_executor": {
-                        "bulk_size": 2,
-                        "bulk_throttle_time_in_ms": 300,
-                        "indexer_dir_depth": 100,
-                        "scheduler_cron_time": ["0 */12 * * *"],
-                    },
-                    "heartbeat": {
-                        # "interval_in_seconds": 300,
-                        "miss_until_inactive": 1,
-                    },
+            "agent_defaults": {
+                "agent_control": {
+                    "retry": {
+                        "attempts": 6,
+                        "delay_in_seconds": 60,
+                        "max_jitter_in_seconds": 10,
+                    }
                 },
-                "agent_control_defaults": {
-                    "update_to_latest": True,
+                "agent_script_executor": {
+                    "bulk_size": 2,
+                    "bulk_throttle_time_in_ms": 300,
+                    "indexer_dir_depth": 100,
+                    "scheduler_cron_time": [
+                        {"cron": "0 */12 * * *", "max_delay_seconds": 30}
+                    ],
+                },
+                "heartbeat": {
+                    # "interval_in_seconds": 300,
+                    "miss_until_inactive": 1,
                 },
-            }
+            },
+            "agent_control_defaults": {
+                "update_to_latest": True,
+            },
         }
         with self.assertRaises(RequiredArgument):
             self.gmp.modify_agent_control_scan_config(
@@ -599,30 +654,30 @@ def test_modify_agent_control_scan_config_missing_heartbeat_miss_until_inactive_
         self,
     ):
         cfg = {
-            "config_defaults": {
-                "agent_defaults": {
-                    "agent_control": {
-                        "retry": {
-                            "attempts": 6,
-                            "delay_in_seconds": 60,
-                            "max_jitter_in_seconds": 10,
-                        }
-                    },
-                    "agent_script_executor": {
-                        "bulk_size": 2,
-                        "bulk_throttle_time_in_ms": 300,
-                        "indexer_dir_depth": 100,
-                        "scheduler_cron_time": ["0 */12 * * *"],
-                    },
-                    "heartbeat": {
-                        "interval_in_seconds": 300,
-                        # "miss_until_inactive": 1,
-                    },
+            "agent_defaults": {
+                "agent_control": {
+                    "retry": {
+                        "attempts": 6,
+                        "delay_in_seconds": 60,
+                        "max_jitter_in_seconds": 10,
+                    }
                 },
-                "agent_control_defaults": {
-                    "update_to_latest": True,
+                "agent_script_executor": {
+                    "bulk_size": 2,
+                    "bulk_throttle_time_in_ms": 300,
+                    "indexer_dir_depth": 100,
+                    "scheduler_cron_time": [
+                        {"cron": "0 */12 * * *", "max_delay_seconds": 30}
+                    ],
                 },
-            }
+                "heartbeat": {
+                    "interval_in_seconds": 300,
+                    # "miss_until_inactive": 1,
+                },
+            },
+            "agent_control_defaults": {
+                "update_to_latest": True,
+            },
         }
         with self.assertRaises(RequiredArgument):
             self.gmp.modify_agent_control_scan_config(
@@ -633,28 +688,28 @@ def test_modify_agent_control_scan_config_agent_control_defaults_raises(
         self,
     ):
         cfg = {
-            "config_defaults": {
-                "agent_defaults": {
-                    "agent_control": {
-                        "retry": {
-                            "attempts": 6,
-                            "delay_in_seconds": 60,
-                            "max_jitter_in_seconds": 10,
-                        }
-                    },
-                    "agent_script_executor": {
-                        "bulk_size": 2,
-                        "bulk_throttle_time_in_ms": 300,
-                        "indexer_dir_depth": 100,
-                        "scheduler_cron_time": ["0 */12 * * *"],
-                    },
-                    "heartbeat": {
-                        "interval_in_seconds": 300,
-                        "miss_until_inactive": 1,
-                    },
+            "agent_defaults": {
+                "agent_control": {
+                    "retry": {
+                        "attempts": 6,
+                        "delay_in_seconds": 60,
+                        "max_jitter_in_seconds": 10,
+                    }
+                },
+                "agent_script_executor": {
+                    "bulk_size": 2,
+                    "bulk_throttle_time_in_ms": 300,
+                    "indexer_dir_depth": 100,
+                    "scheduler_cron_time": [
+                        {"cron": "0 */12 * * *", "max_delay_seconds": 30}
+                    ],
+                },
+                "heartbeat": {
+                    "interval_in_seconds": 300,
+                    "miss_until_inactive": 1,
                 },
-                # "agent_control_defaults": missing,
-            }
+            },
+            # "agent_control_defaults": missing,
         }
         with self.assertRaises(RequiredArgument):
             self.gmp.modify_agent_control_scan_config(
@@ -665,32 +720,32 @@ def test_modify_agent_control_scan_config_missing_update_to_latest_raises(
         self,
     ):
         cfg = {
-            "config_defaults": {
-                "agent_defaults": {
-                    "agent_control": {
-                        "retry": {
-                            "attempts": 6,
-                            "delay_in_seconds": 60,
-                            "max_jitter_in_seconds": 10,
-                        }
-                    },
-                    "agent_script_executor": {
-                        "bulk_size": 2,
-                        "bulk_throttle_time_in_ms": 300,
-                        "indexer_dir_depth": 100,
-                        "scheduler_cron_time": ["0 */12 * * *"],
-                    },
-                    "heartbeat": {
-                        "interval_in_seconds": 300,
-                        "miss_until_inactive": 1,
-                    },
+            "agent_defaults": {
+                "agent_control": {
+                    "retry": {
+                        "attempts": 6,
+                        "delay_in_seconds": 60,
+                        "max_jitter_in_seconds": 10,
+                    }
                 },
-                "agent_control_defaults": {
-                    # "update_to_latest": True,
+                "agent_script_executor": {
+                    "bulk_size": 2,
+                    "bulk_throttle_time_in_ms": 300,
+                    "indexer_dir_depth": 100,
+                    "scheduler_cron_time": [
+                        {"cron": "0 */12 * * *", "max_delay_seconds": 30}
+                    ],
+                },
+                "heartbeat": {
+                    "interval_in_seconds": 300,
+                    "miss_until_inactive": 1,
                 },
-            }
+            },
+            "agent_control_defaults": {
+                # "update_to_latest": True,
+            },
         }
-        with self.assertRaises(RequiredArgument):
+        with self.assertRaises(InvalidArgumentType):
             self.gmp.modify_agent_control_scan_config(
                 "fb6451bf-ec5a-45a8-8bab-5cf4b862e51b", config=cfg
             )
@@ -712,8 +767,8 @@ def test_modify_agent_control_scan_config_wrong_update_to_latest_raises(
                     "bulk_throttle_time_in_ms": 100,
                     "indexer_dir_depth": 10,
                     "scheduler_cron_time": [
-                        "0 23 * * *",
-                        "0 22 * * *",
+                        {"cron": "0 23 * * *", "max_delay_seconds": 30},
+                        {"cron": "0 22 * * *", "max_delay_seconds": 60},
                     ],
                 },
                 "heartbeat": {
diff --git a/tests/protocols/gmpnext/entities/agents/test_modify_agents.py b/tests/protocols/gmpnext/entities/agents/test_modify_agents.py
index d2db4d00..544282ba 100644
--- a/tests/protocols/gmpnext/entities/agents/test_modify_agents.py
+++ b/tests/protocols/gmpnext/entities/agents/test_modify_agents.py
@@ -2,7 +2,7 @@
 #
 # SPDX-License-Identifier: GPL-3.0-or-later
 
-from gvm.errors import RequiredArgument
+from gvm.errors import InvalidArgumentType, RequiredArgument
 
 
 class GmpModifyAgentsTestMixin:
@@ -52,7 +52,9 @@ def test_modify_agents_with_full_config_and_comment(self):
                 "bulk_size": 2,
                 "bulk_throttle_time_in_ms": 300,
                 "indexer_dir_depth": 100,
-                "scheduler_cron_time": ["0 */12 * * *"],
+                "scheduler_cron_time": [
+                    {"cron": "0 */12 * * *", "max_delay_seconds": 30}
+                ],
             },
             "heartbeat": {"interval_in_seconds": 300, "miss_until_inactive": 1},
         }
@@ -83,7 +85,10 @@ def test_modify_agents_with_full_config_and_comment(self):
             b"<bulk_throttle_time_in_ms>300</bulk_throttle_time_in_ms>"
             b"<indexer_dir_depth>100</indexer_dir_depth>"
             b'<scheduler_cron_time is_list="1">'
-            b"<item>0 */12 * * *</item>"
+            b"<item>"
+            b"<cron>0 */12 * * *</cron>"
+            b"<max_delay_seconds>30</max_delay_seconds>"
+            b"</item>"
             b"</scheduler_cron_time>"
             b"</agent_script_executor>"
             b"<heartbeat>"
@@ -108,7 +113,9 @@ def test_modify_agents_omits_optional_elements_when_none(self):
                 "bulk_size": 2,
                 "bulk_throttle_time_in_ms": 300,
                 "indexer_dir_depth": 100,
-                "scheduler_cron_time": ["0 */12 * * *"],
+                "scheduler_cron_time": [
+                    {"cron": "0 */12 * * *", "max_delay_seconds": 30}
+                ],
             },
             "heartbeat": {
                 "interval_in_seconds": 300,
@@ -140,7 +147,10 @@ def test_modify_agents_omits_optional_elements_when_none(self):
             b"<bulk_throttle_time_in_ms>300</bulk_throttle_time_in_ms>"
             b"<indexer_dir_depth>100</indexer_dir_depth>"
             b'<scheduler_cron_time is_list="1">'
-            b"<item>0 */12 * * *</item>"
+            b"<item>"
+            b"<cron>0 */12 * * *</cron>"
+            b"<max_delay_seconds>30</max_delay_seconds>"
+            b"</item>"
             b"</scheduler_cron_time>"
             b"</agent_script_executor>"
             b"<heartbeat>"
@@ -214,7 +224,10 @@ def test_modify_agents_scheduler_with_empty_item_raises(self):
                 "bulk_size": 2,
                 "bulk_throttle_time_in_ms": 300,
                 "indexer_dir_depth": 100,
-                "scheduler_cron_time": ["", "   "],
+                "scheduler_cron_time": [
+                    {"cron": "", "max_delay_seconds": 30},
+                    {"cron": "   ", "max_delay_seconds": 30},
+                ],
             },
             "heartbeat": {"interval_in_seconds": 300, "miss_until_inactive": 1},
         }
@@ -228,7 +241,9 @@ def test_modify_agents_missing_agent_control_raises(self):
                 "bulk_size": 2,
                 "bulk_throttle_time_in_ms": 300,
                 "indexer_dir_depth": 100,
-                "scheduler_cron_time": ["0 */12 * * *"],
+                "scheduler_cron_time": [
+                    {"cron": "0 */12 * * *", "max_delay_seconds": 30}
+                ],
             },
             "heartbeat": {"interval_in_seconds": 300, "miss_until_inactive": 1},
         }
@@ -244,7 +259,9 @@ def test_modify_agents_missing_retry_block_raises(self):
                 "bulk_size": 2,
                 "bulk_throttle_time_in_ms": 300,
                 "indexer_dir_depth": 100,
-                "scheduler_cron_time": ["0 */12 * * *"],
+                "scheduler_cron_time": [
+                    {"cron": "0 */12 * * *", "max_delay_seconds": 30}
+                ],
             },
             "heartbeat": {"interval_in_seconds": 300, "miss_until_inactive": 1},
         }
@@ -264,7 +281,9 @@ def test_modify_agents_missing_retry_attempts_raises(self):
                 "bulk_size": 2,
                 "bulk_throttle_time_in_ms": 300,
                 "indexer_dir_depth": 100,
-                "scheduler_cron_time": ["0 */12 * * *"],
+                "scheduler_cron_time": [
+                    {"cron": "0 */12 * * *", "max_delay_seconds": 30}
+                ],
             },
             "heartbeat": {"interval_in_seconds": 300, "miss_until_inactive": 1},
         }
@@ -284,7 +303,9 @@ def test_modify_agents_missing_retry_delay_raises(self):
                 "bulk_size": 2,
                 "bulk_throttle_time_in_ms": 300,
                 "indexer_dir_depth": 100,
-                "scheduler_cron_time": ["0 */12 * * *"],
+                "scheduler_cron_time": [
+                    {"cron": "0 */12 * * *", "max_delay_seconds": 30}
+                ],
             },
             "heartbeat": {"interval_in_seconds": 300, "miss_until_inactive": 1},
         }
@@ -304,7 +325,9 @@ def test_modify_agents_missing_retry_max_jitter_raises(self):
                 "bulk_size": 2,
                 "bulk_throttle_time_in_ms": 300,
                 "indexer_dir_depth": 100,
-                "scheduler_cron_time": ["0 */12 * * *"],
+                "scheduler_cron_time": [
+                    {"cron": "0 */12 * * *", "max_delay_seconds": 30}
+                ],
             },
             "heartbeat": {"interval_in_seconds": 300, "miss_until_inactive": 1},
         }
@@ -339,7 +362,9 @@ def test_modify_agents_missing_bulk_size_raises(self):
                 # "bulk_size": 2,
                 "bulk_throttle_time_in_ms": 300,
                 "indexer_dir_depth": 100,
-                "scheduler_cron_time": ["0 */12 * * *"],
+                "scheduler_cron_time": [
+                    {"cron": "0 */12 * * *", "max_delay_seconds": 30}
+                ],
             },
             "heartbeat": {"interval_in_seconds": 300, "miss_until_inactive": 1},
         }
@@ -359,7 +384,9 @@ def test_modify_agents_missing_bulk_throttle_time_in_ms_raises(self):
                 "bulk_size": 2,
                 # "bulk_throttle_time_in_ms": 300,
                 "indexer_dir_depth": 100,
-                "scheduler_cron_time": ["0 */12 * * *"],
+                "scheduler_cron_time": [
+                    {"cron": "0 */12 * * *", "max_delay_seconds": 30}
+                ],
             },
             "heartbeat": {"interval_in_seconds": 300, "miss_until_inactive": 1},
         }
@@ -379,7 +406,9 @@ def test_modify_agents_missing_indexer_dir_depth_raises(self):
                 "bulk_size": 2,
                 "bulk_throttle_time_in_ms": 300,
                 # "indexer_dir_depth": 100,
-                "scheduler_cron_time": ["0 */12 * * *"],
+                "scheduler_cron_time": [
+                    {"cron": "0 */12 * * *", "max_delay_seconds": 30}
+                ],
             },
             "heartbeat": {"interval_in_seconds": 300, "miss_until_inactive": 1},
         }
@@ -399,7 +428,9 @@ def test_modify_agents_missing_heartbeat_block_raises(self):
                 "bulk_size": 2,
                 "bulk_throttle_time_in_ms": 300,
                 "indexer_dir_depth": 100,
-                "scheduler_cron_time": ["0 */12 * * *"],
+                "scheduler_cron_time": [
+                    {"cron": "0 */12 * * *", "max_delay_seconds": 30}
+                ],
             },
             # "heartbeat": missing
         }
@@ -419,7 +450,9 @@ def test_modify_agents_missing_heartbeat_interval_raises(self):
                 "bulk_size": 2,
                 "bulk_throttle_time_in_ms": 300,
                 "indexer_dir_depth": 100,
-                "scheduler_cron_time": ["0 */12 * * *"],
+                "scheduler_cron_time": [
+                    {"cron": "0 */12 * * *", "max_delay_seconds": 30}
+                ],
             },
             "heartbeat": {
                 # "interval_in_seconds": 300,
@@ -442,7 +475,9 @@ def test_modify_agents_missing_heartbeat_miss_until_inactive_raises(self):
                 "bulk_size": 2,
                 "bulk_throttle_time_in_ms": 300,
                 "indexer_dir_depth": 100,
-                "scheduler_cron_time": ["0 */12 * * *"],
+                "scheduler_cron_time": [
+                    {"cron": "0 */12 * * *", "max_delay_seconds": 30}
+                ],
             },
             "heartbeat": {
                 "interval_in_seconds": 300,
@@ -465,9 +500,132 @@ def test_modify_agents_agent_control_not_mapping_raises(self):
                 "bulk_size": 2,
                 "bulk_throttle_time_in_ms": 300,
                 "indexer_dir_depth": 100,
-                "scheduler_cron_time": ["0 */12 * * *"],
+                "scheduler_cron_time": [
+                    {"cron": "0 */12 * * *", "max_delay_seconds": 30}
+                ],
             },
             "heartbeat": {"interval_in_seconds": 300, "miss_until_inactive": 1},
         }
         with self.assertRaises(RequiredArgument):
             self.gmp.modify_agents(agent_ids=["agent-123"], config=cfg)
+
+    def test_modify_agents_scheduler_zero_max_delay(self):
+        cfg = {
+            "agent_control": {
+                "retry": {
+                    "attempts": 6,
+                    "delay_in_seconds": 60,
+                    "max_jitter_in_seconds": 10,
+                }
+            },
+            "agent_script_executor": {
+                "bulk_size": 2,
+                "bulk_throttle_time_in_ms": 300,
+                "indexer_dir_depth": 100,
+                "scheduler_cron_time": [
+                    {"cron": "0 */12 * * *", "max_delay_seconds": 0}
+                ],
+            },
+            "heartbeat": {"interval_in_seconds": 300, "miss_until_inactive": 1},
+        }
+
+        self.gmp.modify_agents(agent_ids=["agent-123"], config=cfg)
+
+        self.connection.send.has_been_called_with(
+            b"<modify_agent>"
+            b'<agents><agent id="agent-123"/></agents>'
+            b"<config>"
+            b"<agent_control>"
+            b"<retry>"
+            b"<attempts>6</attempts>"
+            b"<delay_in_seconds>60</delay_in_seconds>"
+            b"<max_jitter_in_seconds>10</max_jitter_in_seconds>"
+            b"</retry>"
+            b"</agent_control>"
+            b"<agent_script_executor>"
+            b"<bulk_size>2</bulk_size>"
+            b"<bulk_throttle_time_in_ms>300</bulk_throttle_time_in_ms>"
+            b"<indexer_dir_depth>100</indexer_dir_depth>"
+            b'<scheduler_cron_time is_list="1">'
+            b"<item><cron>0 */12 * * *</cron>"
+            b"<max_delay_seconds>0</max_delay_seconds></item>"
+            b"</scheduler_cron_time>"
+            b"</agent_script_executor>"
+            b"<heartbeat>"
+            b"<interval_in_seconds>300</interval_in_seconds>"
+            b"<miss_until_inactive>1</miss_until_inactive>"
+            b"</heartbeat>"
+            b"</config>"
+            b"</modify_agent>"
+        )
+
+    def test_modify_agents_scheduler_missing_max_delay_raises(self):
+        cfg = {
+            "agent_control": {
+                "retry": {
+                    "attempts": 6,
+                    "delay_in_seconds": 60,
+                    "max_jitter_in_seconds": 10,
+                }
+            },
+            "agent_script_executor": {
+                "bulk_size": 2,
+                "bulk_throttle_time_in_ms": 300,
+                "indexer_dir_depth": 100,
+                "scheduler_cron_time": [{"cron": "0 */12 * * *"}],
+            },
+            "heartbeat": {"interval_in_seconds": 300, "miss_until_inactive": 1},
+        }
+
+        with self.assertRaises(InvalidArgumentType):
+            self.gmp.modify_agents(agent_ids=["agent-123"], config=cfg)
+
+    def test_modify_agents_scheduler_negative_max_delay_raises(self):
+        cfg = {
+            "agent_control": {
+                "retry": {
+                    "attempts": 6,
+                    "delay_in_seconds": 60,
+                    "max_jitter_in_seconds": 10,
+                }
+            },
+            "agent_script_executor": {
+                "bulk_size": 2,
+                "bulk_throttle_time_in_ms": 300,
+                "indexer_dir_depth": 100,
+                "scheduler_cron_time": [
+                    {"cron": "0 */12 * * *", "max_delay_seconds": -1}
+                ],
+            },
+            "heartbeat": {"interval_in_seconds": 300, "miss_until_inactive": 1},
+        }
+
+        with self.assertRaises(InvalidArgumentType):
+            self.gmp.modify_agents(agent_ids=["agent-123"], config=cfg)
+
+    def test_modify_agents_scheduler_item_not_mapping_raises(self):
+        cfg = {
+            "agent_control": {
+                "retry": {
+                    "attempts": 6,
+                    "delay_in_seconds": 60,
+                    "max_jitter_in_seconds": 10,
+                }
+            },
+            "agent_script_executor": {
+                "bulk_size": 2,
+                "bulk_throttle_time_in_ms": 300,
+                "indexer_dir_depth": 100,
+                "scheduler_cron_time": [
+                    {"cron": "0 23 * * *", "max_delay_seconds": 30},
+                    "0 22 * * *",
+                ],
+            },
+            "heartbeat": {
+                "interval_in_seconds": 300,
+                "miss_until_inactive": 1,
+            },
+        }
+
+        with self.assertRaises(InvalidArgumentType):
+            self.gmp.modify_agents(agent_ids=["agent-123"], config=cfg)