diff --git a/api/core/workflow/entities/graph_runtime_state.py b/api/core/workflow/entities/graph_runtime_state.py
index 36662a065e..c06a62d1e7 100644
--- a/api/core/workflow/entities/graph_runtime_state.py
+++ b/api/core/workflow/entities/graph_runtime_state.py
@@ -25,7 +25,7 @@ class GraphRuntimeState(BaseModel):
         llm_usage: LLMUsage | None = None,
         outputs: dict[str, Any] | None = None,
         node_run_steps: int = 0,
-        **kwargs,
+        **kwargs: object,
     ):
         """Initialize the GraphRuntimeState with validation."""
         super().__init__(**kwargs)
diff --git a/api/core/workflow/entities/variable_pool.py b/api/core/workflow/entities/variable_pool.py
index fb0794844e..db5cbeca03 100644
--- a/api/core/workflow/entities/variable_pool.py
+++ b/api/core/workflow/entities/variable_pool.py
@@ -14,7 +14,7 @@ from core.workflow.constants import CONVERSATION_VARIABLE_NODE_ID, ENVIRONMENT_V
 from core.workflow.system_variable import SystemVariable
 from factories import variable_factory
 
-VariableValue = Union[str, int, float, dict, list, File]
+VariableValue = Union[str, int, float, dict[str, object], list[object], File]
 
 VARIABLE_PATTERN = re.compile(r"\{\{#([a-zA-Z0-9_]{1,50}(?:\.[a-zA-Z_][a-zA-Z0-9_]{0,29}){1,10})#\}\}")
 
@@ -40,11 +40,11 @@ class VariablePool(BaseModel):
     )
     environment_variables: Sequence[VariableUnion] = Field(
         description="Environment variables.",
-        default_factory=list,
+        default_factory=list[VariableUnion],
     )
     conversation_variables: Sequence[VariableUnion] = Field(
         description="Conversation variables.",
-        default_factory=list,
+        default_factory=list[VariableUnion],
     )
 
     def model_post_init(self, context: Any, /) -> None:
@@ -191,7 +191,7 @@ class VariablePool(BaseModel):
 
     def convert_template(self, template: str, /):
         parts = VARIABLE_PATTERN.split(template)
-        segments = []
+        segments: list[Segment] = []
         for part in filter(lambda x: x, parts):
             if "." in part and (variable := self.get(part.split("."))):
                 segments.append(variable)
diff --git a/api/core/workflow/graph/graph_runtime_state_protocol.py b/api/core/workflow/graph/graph_runtime_state_protocol.py
index a5c8db333a..d7961405ca 100644
--- a/api/core/workflow/graph/graph_runtime_state_protocol.py
+++ b/api/core/workflow/graph/graph_runtime_state_protocol.py
@@ -1,16 +1,18 @@
+from collections.abc import Mapping
 from typing import Any, Protocol
 
 from core.model_runtime.entities.llm_entities import LLMUsage
+from core.variables.segments import Segment
 
 
 class ReadOnlyVariablePool(Protocol):
     """Read-only interface for VariablePool."""
 
-    def get(self, node_id: str, variable_key: str) -> Any:
+    def get(self, node_id: str, variable_key: str) -> Segment | None:
         """Get a variable value (read-only)."""
         ...
 
-    def get_all_by_node(self, node_id: str) -> dict[str, Any]:
+    def get_all_by_node(self, node_id: str) -> Mapping[str, object]:
         """Get all variables for a node (read-only)."""
         ...
 
diff --git a/api/core/workflow/graph/read_only_state_wrapper.py b/api/core/workflow/graph/read_only_state_wrapper.py
index 3562106a4c..255bb5adee 100644
--- a/api/core/workflow/graph/read_only_state_wrapper.py
+++ b/api/core/workflow/graph/read_only_state_wrapper.py
@@ -1,7 +1,9 @@
+from collections.abc import Mapping
 from copy import deepcopy
 from typing import Any
 
 from core.model_runtime.entities.llm_entities import LLMUsage
+from core.variables.segments import Segment
 from core.workflow.entities.graph_runtime_state import GraphRuntimeState
 from core.workflow.entities.variable_pool import VariablePool
 
@@ -12,19 +14,18 @@ class ReadOnlyVariablePoolWrapper:
     def __init__(self, variable_pool: VariablePool):
         self._variable_pool = variable_pool
 
-    def get(self, node_id: str, variable_key: str) -> Any:
+    def get(self, node_id: str, variable_key: str) -> Segment | None:
         """Get a variable value (returns a defensive copy)."""
-        value = self._variable_pool.get(node_id, variable_key)
+        value = self._variable_pool.get([node_id, variable_key])
         return deepcopy(value) if value is not None else None
 
-    def get_all_by_node(self, node_id: str) -> dict[str, Any]:
+    def get_all_by_node(self, node_id: str) -> Mapping[str, object]:
         """Get all variables for a node (returns defensive copies)."""
-        variables = {}
+        variables: dict[str, object] = {}
         if node_id in self._variable_pool.variable_dictionary:
             for key, var in self._variable_pool.variable_dictionary[node_id].items():
-                # FIXME(-LAN-): Handle the actual Variable object structure
-                value = var.value if hasattr(var, "value") else var
-                variables[key] = deepcopy(value)
+                # Variables have a value property that contains the actual data
+                variables[key] = deepcopy(var.value)
         return variables
 
 
diff --git a/api/core/workflow/node_events/base.py b/api/core/workflow/node_events/base.py
index 3e9e239d30..7fec47e21f 100644
--- a/api/core/workflow/node_events/base.py
+++ b/api/core/workflow/node_events/base.py
@@ -13,6 +13,11 @@ class NodeEventBase(BaseModel):
     pass
 
 
+def _default_metadata():
+    v: Mapping[WorkflowNodeExecutionMetadataKey, Any] = {}
+    return v
+
+
 class NodeRunResult(BaseModel):
     """
     Node Run Result.
@@ -23,7 +28,7 @@ class NodeRunResult(BaseModel):
     inputs: Mapping[str, Any] = Field(default_factory=dict)
     process_data: Mapping[str, Any] = Field(default_factory=dict)
     outputs: Mapping[str, Any] = Field(default_factory=dict)
-    metadata: Mapping[WorkflowNodeExecutionMetadataKey, Any] = Field(default_factory=dict)
+    metadata: Mapping[WorkflowNodeExecutionMetadataKey, Any] = Field(default_factory=_default_metadata)
     llm_usage: LLMUsage = Field(default_factory=LLMUsage.empty_usage)
 
     edge_source_handle: str = "source"  # source handle id of node with multiple branches
diff --git a/api/core/workflow/utils/condition/processor.py b/api/core/workflow/utils/condition/processor.py
index 8689aa987b..f4bbe9c3c3 100644
--- a/api/core/workflow/utils/condition/processor.py
+++ b/api/core/workflow/utils/condition/processor.py
@@ -1,6 +1,6 @@
 import json
 from collections.abc import Mapping, Sequence
-from typing import Any, Literal, NamedTuple, Union
+from typing import Literal, NamedTuple
 
 from core.file import FileAttribute, file_manager
 from core.variables import ArrayFileSegment
@@ -10,7 +10,7 @@ from core.workflow.entities import VariablePool
 from .entities import Condition, SubCondition, SupportedComparisonOperator
 
 
-def _convert_to_bool(value: Any) -> bool:
+def _convert_to_bool(value: object) -> bool:
     if isinstance(value, int):
         return bool(value)
 
@@ -23,7 +23,7 @@ def _convert_to_bool(value: Any) -> bool:
 
 
 class ConditionCheckResult(NamedTuple):
-    inputs: Sequence[Mapping[str, Any]]
+    inputs: Sequence[Mapping[str, object]]
     group_results: Sequence[bool]
     final_result: bool
 
@@ -36,7 +36,7 @@ class ConditionProcessor:
         conditions: Sequence[Condition],
         operator: Literal["and", "or"],
     ) -> ConditionCheckResult:
-        input_conditions: list[Mapping[str, Any]] = []
+        input_conditions: list[Mapping[str, object]] = []
         group_results: list[bool] = []
 
         for condition in conditions:
@@ -103,8 +103,8 @@ class ConditionProcessor:
 def _evaluate_condition(
     *,
     operator: SupportedComparisonOperator,
-    value: Any,
-    expected: Union[str, Sequence[str], bool | Sequence[bool], None],
+    value: object,
+    expected: str | Sequence[str] | bool | Sequence[bool] | None,
 ) -> bool:
     match operator:
         case "contains":
@@ -144,7 +144,17 @@ def _evaluate_condition(
         case "not in":
             return _assert_not_in(value=value, expected=expected)
         case "all of" if isinstance(expected, list):
-            return _assert_all_of(value=value, expected=expected)
+            # Type narrowing: at this point expected is a list, could be list[str] or list[bool]
+            if all(isinstance(item, str) for item in expected):
+                # Create a new typed list to satisfy type checker
+                str_list: list[str] = [item for item in expected if isinstance(item, str)]
+                return _assert_all_of(value=value, expected=str_list)
+            elif all(isinstance(item, bool) for item in expected):
+                # Create a new typed list to satisfy type checker
+                bool_list: list[bool] = [item for item in expected if isinstance(item, bool)]
+                return _assert_all_of_bool(value=value, expected=bool_list)
+            else:
+                raise ValueError("all of operator expects homogeneous list of strings or booleans")
         case "exists":
             return _assert_exists(value=value)
         case "not exists":
@@ -153,55 +163,73 @@ def _evaluate_condition(
             raise ValueError(f"Unsupported operator: {operator}")
 
 
-def _assert_contains(*, value: Any, expected: Any) -> bool:
+def _assert_contains(*, value: object, expected: object) -> bool:
     if not value:
         return False
 
     if not isinstance(value, (str, list)):
         raise ValueError("Invalid actual value type: string or array")
 
-    if expected not in value:
-        return False
+    # Type checking ensures value is str or list at this point
+    if isinstance(value, str):
+        if not isinstance(expected, str):
+            expected = str(expected)
+        if expected not in value:
+            return False
+    else:  # value is list
+        if expected not in value:
+            return False
     return True
 
 
-def _assert_not_contains(*, value: Any, expected: Any) -> bool:
+def _assert_not_contains(*, value: object, expected: object) -> bool:
     if not value:
         return True
 
     if not isinstance(value, (str, list)):
         raise ValueError("Invalid actual value type: string or array")
 
-    if expected in value:
-        return False
+    # Type checking ensures value is str or list at this point
+    if isinstance(value, str):
+        if not isinstance(expected, str):
+            expected = str(expected)
+        if expected in value:
+            return False
+    else:  # value is list
+        if expected in value:
+            return False
     return True
 
 
-def _assert_start_with(*, value: Any, expected: Any) -> bool:
+def _assert_start_with(*, value: object, expected: object) -> bool:
     if not value:
         return False
 
     if not isinstance(value, str):
         raise ValueError("Invalid actual value type: string")
 
+    if not isinstance(expected, str):
+        raise ValueError("Expected value must be a string for startswith")
     if not value.startswith(expected):
         return False
     return True
 
 
-def _assert_end_with(*, value: Any, expected: Any) -> bool:
+def _assert_end_with(*, value: object, expected: object) -> bool:
     if not value:
         return False
 
     if not isinstance(value, str):
         raise ValueError("Invalid actual value type: string")
 
+    if not isinstance(expected, str):
+        raise ValueError("Expected value must be a string for endswith")
     if not value.endswith(expected):
         return False
     return True
 
 
-def _assert_is(*, value: Any, expected: Any) -> bool:
+def _assert_is(*, value: object, expected: object) -> bool:
     if value is None:
         return False
 
@@ -213,7 +241,7 @@ def _assert_is(*, value: Any, expected: Any) -> bool:
     return True
 
 
-def _assert_is_not(*, value: Any, expected: Any) -> bool:
+def _assert_is_not(*, value: object, expected: object) -> bool:
     if value is None:
         return False
 
@@ -225,19 +253,19 @@ def _assert_is_not(*, value: Any, expected: Any) -> bool:
     return True
 
 
-def _assert_empty(*, value: Any) -> bool:
+def _assert_empty(*, value: object) -> bool:
     if not value:
         return True
     return False
 
 
-def _assert_not_empty(*, value: Any) -> bool:
+def _assert_not_empty(*, value: object) -> bool:
     if value:
         return True
     return False
 
 
-def _assert_equal(*, value: Any, expected: Any) -> bool:
+def _assert_equal(*, value: object, expected: object) -> bool:
     if value is None:
         return False
 
@@ -246,10 +274,16 @@ def _assert_equal(*, value: Any, expected: Any) -> bool:
 
     # Handle boolean comparison
     if isinstance(value, bool):
+        if not isinstance(expected, (bool, int, str)):
+            raise ValueError(f"Cannot convert {type(expected)} to bool")
         expected = bool(expected)
     elif isinstance(value, int):
+        if not isinstance(expected, (int, float, str)):
+            raise ValueError(f"Cannot convert {type(expected)} to int")
         expected = int(expected)
     else:
+        if not isinstance(expected, (int, float, str)):
+            raise ValueError(f"Cannot convert {type(expected)} to float")
         expected = float(expected)
 
     if value != expected:
@@ -257,7 +291,7 @@ def _assert_equal(*, value: Any, expected: Any) -> bool:
     return True
 
 
-def _assert_not_equal(*, value: Any, expected: Any) -> bool:
+def _assert_not_equal(*, value: object, expected: object) -> bool:
     if value is None:
         return False
 
@@ -266,10 +300,16 @@ def _assert_not_equal(*, value: Any, expected: Any) -> bool:
 
     # Handle boolean comparison
     if isinstance(value, bool):
+        if not isinstance(expected, (bool, int, str)):
+            raise ValueError(f"Cannot convert {type(expected)} to bool")
         expected = bool(expected)
     elif isinstance(value, int):
+        if not isinstance(expected, (int, float, str)):
+            raise ValueError(f"Cannot convert {type(expected)} to int")
         expected = int(expected)
     else:
+        if not isinstance(expected, (int, float, str)):
+            raise ValueError(f"Cannot convert {type(expected)} to float")
         expected = float(expected)
 
     if value == expected:
@@ -277,7 +317,7 @@ def _assert_not_equal(*, value: Any, expected: Any) -> bool:
     return True
 
 
-def _assert_greater_than(*, value: Any, expected: Any) -> bool:
+def _assert_greater_than(*, value: object, expected: object) -> bool:
     if value is None:
         return False
 
@@ -285,8 +325,12 @@ def _assert_greater_than(*, value: Any, expected: Any) -> bool:
         raise ValueError("Invalid actual value type: number")
 
     if isinstance(value, int):
+        if not isinstance(expected, (int, float, str)):
+            raise ValueError(f"Cannot convert {type(expected)} to int")
         expected = int(expected)
     else:
+        if not isinstance(expected, (int, float, str)):
+            raise ValueError(f"Cannot convert {type(expected)} to float")
         expected = float(expected)
 
     if value <= expected:
@@ -294,7 +338,7 @@ def _assert_greater_than(*, value: Any, expected: Any) -> bool:
     return True
 
 
-def _assert_less_than(*, value: Any, expected: Any) -> bool:
+def _assert_less_than(*, value: object, expected: object) -> bool:
     if value is None:
         return False
 
@@ -302,8 +346,12 @@ def _assert_less_than(*, value: Any, expected: Any) -> bool:
         raise ValueError("Invalid actual value type: number")
 
     if isinstance(value, int):
+        if not isinstance(expected, (int, float, str)):
+            raise ValueError(f"Cannot convert {type(expected)} to int")
         expected = int(expected)
     else:
+        if not isinstance(expected, (int, float, str)):
+            raise ValueError(f"Cannot convert {type(expected)} to float")
         expected = float(expected)
 
     if value >= expected:
@@ -311,7 +359,7 @@ def _assert_less_than(*, value: Any, expected: Any) -> bool:
     return True
 
 
-def _assert_greater_than_or_equal(*, value: Any, expected: Any) -> bool:
+def _assert_greater_than_or_equal(*, value: object, expected: object) -> bool:
     if value is None:
         return False
 
@@ -319,8 +367,12 @@ def _assert_greater_than_or_equal(*, value: Any, expected: Any) -> bool:
         raise ValueError("Invalid actual value type: number")
 
     if isinstance(value, int):
+        if not isinstance(expected, (int, float, str)):
+            raise ValueError(f"Cannot convert {type(expected)} to int")
         expected = int(expected)
     else:
+        if not isinstance(expected, (int, float, str)):
+            raise ValueError(f"Cannot convert {type(expected)} to float")
         expected = float(expected)
 
     if value < expected:
@@ -328,7 +380,7 @@ def _assert_greater_than_or_equal(*, value: Any, expected: Any) -> bool:
     return True
 
 
-def _assert_less_than_or_equal(*, value: Any, expected: Any) -> bool:
+def _assert_less_than_or_equal(*, value: object, expected: object) -> bool:
     if value is None:
         return False
 
@@ -336,8 +388,12 @@ def _assert_less_than_or_equal(*, value: Any, expected: Any) -> bool:
         raise ValueError("Invalid actual value type: number")
 
     if isinstance(value, int):
+        if not isinstance(expected, (int, float, str)):
+            raise ValueError(f"Cannot convert {type(expected)} to int")
         expected = int(expected)
     else:
+        if not isinstance(expected, (int, float, str)):
+            raise ValueError(f"Cannot convert {type(expected)} to float")
         expected = float(expected)
 
     if value > expected:
@@ -345,19 +401,19 @@ def _assert_less_than_or_equal(*, value: Any, expected: Any) -> bool:
     return True
 
 
-def _assert_null(*, value: Any) -> bool:
+def _assert_null(*, value: object) -> bool:
     if value is None:
         return True
     return False
 
 
-def _assert_not_null(*, value: Any) -> bool:
+def _assert_not_null(*, value: object) -> bool:
     if value is not None:
         return True
     return False
 
 
-def _assert_in(*, value: Any, expected: Any) -> bool:
+def _assert_in(*, value: object, expected: object) -> bool:
     if not value:
         return False
 
@@ -369,7 +425,7 @@ def _assert_in(*, value: Any, expected: Any) -> bool:
     return True
 
 
-def _assert_not_in(*, value: Any, expected: Any) -> bool:
+def _assert_not_in(*, value: object, expected: object) -> bool:
     if not value:
         return True
 
@@ -381,20 +437,33 @@ def _assert_not_in(*, value: Any, expected: Any) -> bool:
     return True
 
 
-def _assert_all_of(*, value: Any, expected: Sequence[str]) -> bool:
+def _assert_all_of(*, value: object, expected: Sequence[str]) -> bool:
     if not value:
         return False
 
-    if not all(item in value for item in expected):
+    # Ensure value is a container that supports 'in' operator
+    if not isinstance(value, (list, tuple, set, str)):
         return False
-    return True
+
+    return all(item in value for item in expected)
 
 
-def _assert_exists(*, value: Any) -> bool:
+def _assert_all_of_bool(*, value: object, expected: Sequence[bool]) -> bool:
+    if not value:
+        return False
+
+    # Ensure value is a container that supports 'in' operator
+    if not isinstance(value, (list, tuple, set)):
+        return False
+
+    return all(item in value for item in expected)
+
+
+def _assert_exists(*, value: object) -> bool:
     return value is not None
 
 
-def _assert_not_exists(*, value: Any) -> bool:
+def _assert_not_exists(*, value: object) -> bool:
     return value is None
 
 
@@ -404,7 +473,7 @@ def _process_sub_conditions(
     operator: Literal["and", "or"],
 ) -> bool:
     files = variable.value
-    group_results = []
+    group_results: list[bool] = []
     for condition in sub_conditions:
         key = FileAttribute(condition.key)
         values = [file_manager.get_attr(file=file, attr=key) for file in files]
@@ -415,14 +484,14 @@ def _process_sub_conditions(
             if expected_value and not expected_value.startswith("."):
                 expected_value = "." + expected_value
 
-            normalized_values = []
+            normalized_values: list[object] = []
             for value in values:
                 if value and isinstance(value, str):
                     if not value.startswith("."):
                         value = "." + value
                 normalized_values.append(value)
             values = normalized_values
-        sub_group_results = [
+        sub_group_results: list[bool] = [
             _evaluate_condition(
                 value=value,
                 operator=condition.comparison_operator,