diff --git a/src/crewai/flow/__init__.py b/src/crewai/flow/__init__.py
index 48a49666d..b15c0a720 100644
--- a/src/crewai/flow/__init__.py
+++ b/src/crewai/flow/__init__.py
@@ -1,5 +1,4 @@
-from crewai.flow.flow import Flow, start, listen, or_, and_, router
+from crewai.flow.flow import Flow, and_, listen, or_, router, start
 from crewai.flow.persistence import persist
 
-__all__ = ["Flow", "start", "listen", "or_", "and_", "router", "persist"]
-
+__all__ = ["Flow", "and_", "listen", "or_", "persist", "router", "start"]
diff --git a/src/crewai/flow/flow_trackable.py b/src/crewai/flow/flow_trackable.py
index 3cdbdeed3..30303c272 100644
--- a/src/crewai/flow/flow_trackable.py
+++ b/src/crewai/flow/flow_trackable.py
@@ -1,5 +1,4 @@
 import inspect
-from typing import Optional
 
 from pydantic import BaseModel, Field, InstanceOf, model_validator
 
@@ -14,7 +13,7 @@ class FlowTrackable(BaseModel):
     inspecting the call stack.
     """
 
-    parent_flow: Optional[InstanceOf[Flow]] = Field(
+    parent_flow: InstanceOf[Flow] | None = Field(
         default=None,
         description="The parent flow of the instance, if it was created inside a flow.",
     )
diff --git a/src/crewai/flow/flow_visualizer.py b/src/crewai/flow/flow_visualizer.py
index a70e91a18..5b50c3844 100644
--- a/src/crewai/flow/flow_visualizer.py
+++ b/src/crewai/flow/flow_visualizer.py
@@ -1,14 +1,13 @@
 # flow_visualizer.py
 
 import os
-from pathlib import Path
 
-from pyvis.network import Network
+from pyvis.network import Network  # type: ignore[import-untyped]
 
 from crewai.flow.config import COLORS, NODE_STYLES
 from crewai.flow.html_template_handler import HTMLTemplateHandler
 from crewai.flow.legend_generator import generate_legend_items_html, get_legend_items
-from crewai.flow.path_utils import safe_path_join, validate_path_exists
+from crewai.flow.path_utils import safe_path_join
 from crewai.flow.utils import calculate_node_levels
 from crewai.flow.visualization_utils import (
     add_edges,
@@ -34,13 +33,13 @@ class FlowPlot:
         ValueError
             If flow object is invalid or missing required attributes.
         """
-        if not hasattr(flow, '_methods'):
+        if not hasattr(flow, "_methods"):
             raise ValueError("Invalid flow object: missing '_methods' attribute")
-        if not hasattr(flow, '_listeners'):
+        if not hasattr(flow, "_listeners"):
             raise ValueError("Invalid flow object: missing '_listeners' attribute")
-        if not hasattr(flow, '_start_methods'):
+        if not hasattr(flow, "_start_methods"):
             raise ValueError("Invalid flow object: missing '_start_methods' attribute")
-            
+
         self.flow = flow
         self.colors = COLORS
         self.node_styles = NODE_STYLES
@@ -65,7 +64,7 @@ class FlowPlot:
         """
         if not filename or not isinstance(filename, str):
             raise ValueError("Filename must be a non-empty string")
-            
+
         try:
             # Initialize network
             net = Network(
@@ -96,32 +95,34 @@ class FlowPlot:
             try:
                 node_levels = calculate_node_levels(self.flow)
             except Exception as e:
-                raise ValueError(f"Failed to calculate node levels: {str(e)}")
+                raise ValueError(f"Failed to calculate node levels: {e!s}") from e
 
             # Compute positions
             try:
                 node_positions = compute_positions(self.flow, node_levels)
             except Exception as e:
-                raise ValueError(f"Failed to compute node positions: {str(e)}")
+                raise ValueError(f"Failed to compute node positions: {e!s}") from e
 
             # Add nodes to the network
             try:
                 add_nodes_to_network(net, self.flow, node_positions, self.node_styles)
             except Exception as e:
-                raise RuntimeError(f"Failed to add nodes to network: {str(e)}")
+                raise RuntimeError(f"Failed to add nodes to network: {e!s}") from e
 
             # Add edges to the network
             try:
                 add_edges(net, self.flow, node_positions, self.colors)
             except Exception as e:
-                raise RuntimeError(f"Failed to add edges to network: {str(e)}")
+                raise RuntimeError(f"Failed to add edges to network: {e!s}") from e
 
             # Generate HTML
             try:
                 network_html = net.generate_html()
                 final_html_content = self._generate_final_html(network_html)
             except Exception as e:
-                raise RuntimeError(f"Failed to generate network visualization: {str(e)}")
+                raise RuntimeError(
+                    f"Failed to generate network visualization: {e!s}"
+                ) from e
 
             # Save the final HTML content to the file
             try:
@@ -129,12 +130,16 @@ class FlowPlot:
                     f.write(final_html_content)
                 print(f"Plot saved as {filename}.html")
             except IOError as e:
-                raise IOError(f"Failed to save flow visualization to {filename}.html: {str(e)}")
+                raise IOError(
+                    f"Failed to save flow visualization to {filename}.html: {e!s}"
+                ) from e
 
         except (ValueError, RuntimeError, IOError) as e:
             raise e
         except Exception as e:
-            raise RuntimeError(f"Unexpected error during flow visualization: {str(e)}")
+            raise RuntimeError(
+                f"Unexpected error during flow visualization: {e!s}"
+            ) from e
         finally:
             self._cleanup_pyvis_lib()
 
@@ -165,7 +170,9 @@ class FlowPlot:
         try:
             # Extract just the body content from the generated HTML
             current_dir = os.path.dirname(__file__)
-            template_path = safe_path_join("assets", "crewai_flow_visual_template.html", root=current_dir)
+            template_path = safe_path_join(
+                "assets", "crewai_flow_visual_template.html", root=current_dir
+            )
             logo_path = safe_path_join("assets", "crewai_logo.svg", root=current_dir)
 
             if not os.path.exists(template_path):
@@ -179,12 +186,9 @@ class FlowPlot:
             # Generate the legend items HTML
             legend_items = get_legend_items(self.colors)
             legend_items_html = generate_legend_items_html(legend_items)
-            final_html_content = html_handler.generate_final_html(
-                network_body, legend_items_html
-            )
-            return final_html_content
+            return html_handler.generate_final_html(network_body, legend_items_html)
         except Exception as e:
-            raise IOError(f"Failed to generate visualization HTML: {str(e)}")
+            raise IOError(f"Failed to generate visualization HTML: {e!s}") from e
 
     def _cleanup_pyvis_lib(self):
         """
@@ -197,6 +201,7 @@ class FlowPlot:
             lib_folder = safe_path_join("lib", root=os.getcwd())
             if os.path.exists(lib_folder) and os.path.isdir(lib_folder):
                 import shutil
+
                 shutil.rmtree(lib_folder)
         except ValueError as e:
             print(f"Error validating lib folder path: {e}")
diff --git a/src/crewai/flow/html_template_handler.py b/src/crewai/flow/html_template_handler.py
index f0d2d89ad..55567393c 100644
--- a/src/crewai/flow/html_template_handler.py
+++ b/src/crewai/flow/html_template_handler.py
@@ -1,8 +1,7 @@
 import base64
 import re
-from pathlib import Path
 
-from crewai.flow.path_utils import safe_path_join, validate_path_exists
+from crewai.flow.path_utils import validate_path_exists
 
 
 class HTMLTemplateHandler:
@@ -28,7 +27,7 @@ class HTMLTemplateHandler:
             self.template_path = validate_path_exists(template_path, "file")
             self.logo_path = validate_path_exists(logo_path, "file")
         except ValueError as e:
-            raise ValueError(f"Invalid template or logo path: {e}")
+            raise ValueError(f"Invalid template or logo path: {e}") from e
 
     def read_template(self):
         """Read and return the HTML template file contents."""
@@ -53,23 +52,23 @@ class HTMLTemplateHandler:
             if "border" in item:
                 legend_items_html += f"""
                 <div class="legend-item">
-                <div class="legend-color-box" style="background-color: {item['color']}; border: 2px dashed {item['border']};"></div>
-                <div>{item['label']}</div>
+                <div class="legend-color-box" style="background-color: {item["color"]}; border: 2px dashed {item["border"]};"></div>
+                <div>{item["label"]}</div>
                 </div>
                 """
             elif item.get("dashed") is not None:
                 style = "dashed" if item["dashed"] else "solid"
                 legend_items_html += f"""
                 <div class="legend-item">
-                <div class="legend-{style}" style="border-bottom: 2px {style} {item['color']};"></div>
-                <div>{item['label']}</div>
+                <div class="legend-{style}" style="border-bottom: 2px {style} {item["color"]};"></div>
+                <div>{item["label"]}</div>
                 </div>
                 """
             else:
                 legend_items_html += f"""
                 <div class="legend-item">
-                <div class="legend-color-box" style="background-color: {item['color']};"></div>
-                <div>{item['label']}</div>
+                <div class="legend-color-box" style="background-color: {item["color"]};"></div>
+                <div>{item["label"]}</div>
                 </div>
                 """
         return legend_items_html
@@ -79,15 +78,9 @@ class HTMLTemplateHandler:
         html_template = self.read_template()
         logo_svg_base64 = self.encode_logo()
 
-        final_html_content = html_template.replace("{{ title }}", title)
-        final_html_content = final_html_content.replace(
-            "{{ network_content }}", network_body
+        return (
+            html_template.replace("{{ title }}", title)
+            .replace("{{ network_content }}", network_body)
+            .replace("{{ logo_svg_base64 }}", logo_svg_base64)
+            .replace("<!-- LEGEND_ITEMS_PLACEHOLDER -->", legend_items_html)
         )
-        final_html_content = final_html_content.replace(
-            "{{ logo_svg_base64 }}", logo_svg_base64
-        )
-        final_html_content = final_html_content.replace(
-            "<!-- LEGEND_ITEMS_PLACEHOLDER -->", legend_items_html
-        )
-
-        return final_html_content
diff --git a/src/crewai/flow/path_utils.py b/src/crewai/flow/path_utils.py
index 09ae8cd3d..02a893865 100644
--- a/src/crewai/flow/path_utils.py
+++ b/src/crewai/flow/path_utils.py
@@ -5,12 +5,10 @@ This module provides utilities for secure path handling to prevent directory
 traversal attacks and ensure paths remain within allowed boundaries.
 """
 
-import os
 from pathlib import Path
-from typing import List, Union
 
 
-def safe_path_join(*parts: str, root: Union[str, Path, None] = None) -> str:
+def safe_path_join(*parts: str, root: str | Path | None = None) -> str:
     """
     Safely join path components and ensure the result is within allowed boundaries.
 
@@ -43,25 +41,25 @@ def safe_path_join(*parts: str, root: Union[str, Path, None] = None) -> str:
 
         # Establish root directory
         root_path = Path(root).resolve() if root else Path.cwd()
-        
+
         # Join and resolve the full path
         full_path = Path(root_path, *clean_parts).resolve()
-        
+
         # Check if the resolved path is within root
         if not str(full_path).startswith(str(root_path)):
             raise ValueError(
                 f"Invalid path: Potential directory traversal. Path must be within {root_path}"
             )
-            
+
         return str(full_path)
-        
+
     except Exception as e:
         if isinstance(e, ValueError):
             raise
-        raise ValueError(f"Invalid path components: {str(e)}")
+        raise ValueError(f"Invalid path components: {e!s}") from e
 
 
-def validate_path_exists(path: Union[str, Path], file_type: str = "file") -> str:
+def validate_path_exists(path: str | Path, file_type: str = "file") -> str:
     """
     Validate that a path exists and is of the expected type.
 
@@ -84,24 +82,24 @@ def validate_path_exists(path: Union[str, Path], file_type: str = "file") -> str
     """
     try:
         path_obj = Path(path).resolve()
-        
+
         if not path_obj.exists():
             raise ValueError(f"Path does not exist: {path}")
-            
+
         if file_type == "file" and not path_obj.is_file():
             raise ValueError(f"Path is not a file: {path}")
-        elif file_type == "directory" and not path_obj.is_dir():
+        if file_type == "directory" and not path_obj.is_dir():
             raise ValueError(f"Path is not a directory: {path}")
-            
+
         return str(path_obj)
-        
+
     except Exception as e:
         if isinstance(e, ValueError):
             raise
-        raise ValueError(f"Invalid path: {str(e)}")
+        raise ValueError(f"Invalid path: {e!s}") from e
 
 
-def list_files(directory: Union[str, Path], pattern: str = "*") -> List[str]:
+def list_files(directory: str | Path, pattern: str = "*") -> list[str]:
     """
     Safely list files in a directory matching a pattern.
 
@@ -126,10 +124,10 @@ def list_files(directory: Union[str, Path], pattern: str = "*") -> List[str]:
         dir_path = Path(directory).resolve()
         if not dir_path.is_dir():
             raise ValueError(f"Not a directory: {directory}")
-            
+
         return [str(p) for p in dir_path.glob(pattern) if p.is_file()]
-        
+
     except Exception as e:
         if isinstance(e, ValueError):
             raise
-        raise ValueError(f"Error listing files: {str(e)}")
+        raise ValueError(f"Error listing files: {e!s}") from e
diff --git a/src/crewai/flow/persistence/__init__.py b/src/crewai/flow/persistence/__init__.py
index 0b673f6bf..3a542f52c 100644
--- a/src/crewai/flow/persistence/__init__.py
+++ b/src/crewai/flow/persistence/__init__.py
@@ -4,7 +4,7 @@ CrewAI Flow Persistence.
 This module provides interfaces and implementations for persisting flow states.
 """
 
-from typing import Any, Dict, TypeVar, Union
+from typing import Any, TypeVar
 
 from pydantic import BaseModel
 
@@ -12,7 +12,7 @@ from crewai.flow.persistence.base import FlowPersistence
 from crewai.flow.persistence.decorators import persist
 from crewai.flow.persistence.sqlite import SQLiteFlowPersistence
 
-__all__ = ["FlowPersistence", "persist", "SQLiteFlowPersistence"]
+__all__ = ["FlowPersistence", "SQLiteFlowPersistence", "persist"]
 
-StateType = TypeVar('StateType', bound=Union[Dict[str, Any], BaseModel])
-DictStateType = Dict[str, Any]
+StateType = TypeVar("StateType", bound=dict[str, Any] | BaseModel)
+DictStateType = dict[str, Any]
diff --git a/src/crewai/flow/persistence/base.py b/src/crewai/flow/persistence/base.py
index c926f6f34..df7f00add 100644
--- a/src/crewai/flow/persistence/base.py
+++ b/src/crewai/flow/persistence/base.py
@@ -1,53 +1,47 @@
 """Base class for flow state persistence."""
 
 import abc
-from typing import Any, Dict, Optional, Union
+from typing import Any
 
 from pydantic import BaseModel
 
 
 class FlowPersistence(abc.ABC):
     """Abstract base class for flow state persistence.
-    
+
     This class defines the interface that all persistence implementations must follow.
     It supports both structured (Pydantic BaseModel) and unstructured (dict) states.
     """
-    
+
     @abc.abstractmethod
     def init_db(self) -> None:
         """Initialize the persistence backend.
-        
+
         This method should handle any necessary setup, such as:
         - Creating tables
         - Establishing connections
         - Setting up indexes
         """
-        pass
-    
+
     @abc.abstractmethod
     def save_state(
-        self,
-        flow_uuid: str,
-        method_name: str,
-        state_data: Union[Dict[str, Any], BaseModel]
+        self, flow_uuid: str, method_name: str, state_data: dict[str, Any] | BaseModel
     ) -> None:
         """Persist the flow state after method completion.
-        
+
         Args:
             flow_uuid: Unique identifier for the flow instance
             method_name: Name of the method that just completed
             state_data: Current state data (either dict or Pydantic model)
         """
-        pass
-    
+
     @abc.abstractmethod
-    def load_state(self, flow_uuid: str) -> Optional[Dict[str, Any]]:
+    def load_state(self, flow_uuid: str) -> dict[str, Any] | None:
         """Load the most recent state for a given flow UUID.
-        
+
         Args:
             flow_uuid: Unique identifier for the flow instance
-            
+
         Returns:
             The most recent state as a dictionary, or None if no state exists
         """
-        pass
diff --git a/src/crewai/flow/persistence/decorators.py b/src/crewai/flow/persistence/decorators.py
index 7b3bd447c..fc7ed6bc0 100644
--- a/src/crewai/flow/persistence/decorators.py
+++ b/src/crewai/flow/persistence/decorators.py
@@ -24,13 +24,10 @@ Example:
 import asyncio
 import functools
 import logging
+from collections.abc import Callable
 from typing import (
     Any,
-    Callable,
-    Optional,
-    Type,
     TypeVar,
-    Union,
     cast,
 )
 
@@ -48,7 +45,7 @@ LOG_MESSAGES = {
     "save_state": "Saving flow state to memory for ID: {}",
     "save_error": "Failed to persist state for method {}: {}",
     "state_missing": "Flow instance has no state",
-    "id_missing": "Flow state must have an 'id' field for persistence"
+    "id_missing": "Flow state must have an 'id' field for persistence",
 }
 
 
@@ -58,7 +55,13 @@ class PersistenceDecorator:
     _printer = Printer()  # Class-level printer instance
 
     @classmethod
-    def persist_state(cls, flow_instance: Any, method_name: str, persistence_instance: FlowPersistence, verbose: bool = False) -> None:
+    def persist_state(
+        cls,
+        flow_instance: Any,
+        method_name: str,
+        persistence_instance: FlowPersistence,
+        verbose: bool = False,
+    ) -> None:
         """Persist flow state with proper error handling and logging.
 
         This method handles the persistence of flow state data, including proper
@@ -76,22 +79,24 @@ class PersistenceDecorator:
             AttributeError: If flow instance lacks required state attributes
         """
         try:
-            state = getattr(flow_instance, 'state', None)
+            state = getattr(flow_instance, "state", None)
             if state is None:
                 raise ValueError("Flow instance has no state")
 
-            flow_uuid: Optional[str] = None
+            flow_uuid: str | None = None
             if isinstance(state, dict):
-                flow_uuid = state.get('id')
+                flow_uuid = state.get("id")
             elif isinstance(state, BaseModel):
-                flow_uuid = getattr(state, 'id', None)
+                flow_uuid = getattr(state, "id", None)
 
             if not flow_uuid:
                 raise ValueError("Flow state must have an 'id' field for persistence")
 
             # Log state saving only if verbose is True
             if verbose:
-                cls._printer.print(LOG_MESSAGES["save_state"].format(flow_uuid), color="cyan")
+                cls._printer.print(
+                    LOG_MESSAGES["save_state"].format(flow_uuid), color="cyan"
+                )
                 logger.info(LOG_MESSAGES["save_state"].format(flow_uuid))
 
             try:
@@ -104,12 +109,12 @@ class PersistenceDecorator:
                 error_msg = LOG_MESSAGES["save_error"].format(method_name, str(e))
                 cls._printer.print(error_msg, color="red")
                 logger.error(error_msg)
-                raise RuntimeError(f"State persistence failed: {str(e)}") from e
-        except AttributeError:
+                raise RuntimeError(f"State persistence failed: {e!s}") from e
+        except AttributeError as e:
             error_msg = LOG_MESSAGES["state_missing"]
             cls._printer.print(error_msg, color="red")
             logger.error(error_msg)
-            raise ValueError(error_msg)
+            raise ValueError(error_msg) from e
         except (TypeError, ValueError) as e:
             error_msg = LOG_MESSAGES["id_missing"]
             cls._printer.print(error_msg, color="red")
@@ -117,7 +122,7 @@ class PersistenceDecorator:
             raise ValueError(error_msg) from e
 
 
-def persist(persistence: Optional[FlowPersistence] = None, verbose: bool = False):
+def persist(persistence: FlowPersistence | None = None, verbose: bool = False):
     """Decorator to persist flow state.
 
     This decorator can be applied at either the class level or method level.
@@ -144,111 +149,151 @@ def persist(persistence: Optional[FlowPersistence] = None, verbose: bool = False
             def begin(self):
                 pass
     """
-    def decorator(target: Union[Type, Callable[..., T]]) -> Union[Type, Callable[..., T]]:
+
+    def decorator(target: type | Callable[..., T]) -> type | Callable[..., T]:
         """Decorator that handles both class and method decoration."""
         actual_persistence = persistence or SQLiteFlowPersistence()
 
         if isinstance(target, type):
             # Class decoration
-            original_init = getattr(target, "__init__")
+            original_init = target.__init__  # type: ignore[misc]
 
             @functools.wraps(original_init)
             def new_init(self: Any, *args: Any, **kwargs: Any) -> None:
-                if 'persistence' not in kwargs:
-                    kwargs['persistence'] = actual_persistence
+                if "persistence" not in kwargs:
+                    kwargs["persistence"] = actual_persistence
                 original_init(self, *args, **kwargs)
 
-            setattr(target, "__init__", new_init)
+            target.__init__ = new_init  # type: ignore[misc]
 
             # Store original methods to preserve their decorators
-            original_methods = {}
-
-            for name, method in target.__dict__.items():
-                if callable(method) and (
-                    hasattr(method, "__is_start_method__") or
-                    hasattr(method, "__trigger_methods__") or
-                    hasattr(method, "__condition_type__") or
-                    hasattr(method, "__is_flow_method__") or
-                    hasattr(method, "__is_router__")
-                ):
-                    original_methods[name] = method
+            original_methods = {
+                name: method
+                for name, method in target.__dict__.items()
+                if callable(method)
+                and (
+                    hasattr(method, "__is_start_method__")
+                    or hasattr(method, "__trigger_methods__")
+                    or hasattr(method, "__condition_type__")
+                    or hasattr(method, "__is_flow_method__")
+                    or hasattr(method, "__is_router__")
+                )
+            }
 
             # Create wrapped versions of the methods that include persistence
             for name, method in original_methods.items():
                 if asyncio.iscoroutinefunction(method):
                     # Create a closure to capture the current name and method
-                    def create_async_wrapper(method_name: str, original_method: Callable):
+                    def create_async_wrapper(
+                        method_name: str, original_method: Callable
+                    ):
                         @functools.wraps(original_method)
-                        async def method_wrapper(self: Any, *args: Any, **kwargs: Any) -> Any:
+                        async def method_wrapper(
+                            self: Any, *args: Any, **kwargs: Any
+                        ) -> Any:
                             result = await original_method(self, *args, **kwargs)
-                            PersistenceDecorator.persist_state(self, method_name, actual_persistence, verbose)
+                            PersistenceDecorator.persist_state(
+                                self, method_name, actual_persistence, verbose
+                            )
                             return result
+
                         return method_wrapper
 
                     wrapped = create_async_wrapper(name, method)
 
                     # Preserve all original decorators and attributes
-                    for attr in ["__is_start_method__", "__trigger_methods__", "__condition_type__", "__is_router__"]:
+                    for attr in [
+                        "__is_start_method__",
+                        "__trigger_methods__",
+                        "__condition_type__",
+                        "__is_router__",
+                    ]:
                         if hasattr(method, attr):
                             setattr(wrapped, attr, getattr(method, attr))
-                    setattr(wrapped, "__is_flow_method__", True)
+                    wrapped.__is_flow_method__ = True  # type: ignore[attr-defined]
 
                     # Update the class with the wrapped method
                     setattr(target, name, wrapped)
                 else:
                     # Create a closure to capture the current name and method
-                    def create_sync_wrapper(method_name: str, original_method: Callable):
+                    def create_sync_wrapper(
+                        method_name: str, original_method: Callable
+                    ):
                         @functools.wraps(original_method)
                         def method_wrapper(self: Any, *args: Any, **kwargs: Any) -> Any:
                             result = original_method(self, *args, **kwargs)
-                            PersistenceDecorator.persist_state(self, method_name, actual_persistence, verbose)
+                            PersistenceDecorator.persist_state(
+                                self, method_name, actual_persistence, verbose
+                            )
                             return result
+
                         return method_wrapper
 
                     wrapped = create_sync_wrapper(name, method)
 
                     # Preserve all original decorators and attributes
-                    for attr in ["__is_start_method__", "__trigger_methods__", "__condition_type__", "__is_router__"]:
+                    for attr in [
+                        "__is_start_method__",
+                        "__trigger_methods__",
+                        "__condition_type__",
+                        "__is_router__",
+                    ]:
                         if hasattr(method, attr):
                             setattr(wrapped, attr, getattr(method, attr))
-                    setattr(wrapped, "__is_flow_method__", True)
+                    wrapped.__is_flow_method__ = True  # type: ignore[attr-defined]
 
                     # Update the class with the wrapped method
                     setattr(target, name, wrapped)
 
             return target
-        else:
-            # Method decoration
-            method = target
-            setattr(method, "__is_flow_method__", True)
+        # Method decoration
+        method = target
+        method.__is_flow_method__ = True  # type: ignore[attr-defined]
 
-            if asyncio.iscoroutinefunction(method):
-                @functools.wraps(method)
-                async def method_async_wrapper(flow_instance: Any, *args: Any, **kwargs: Any) -> T:
-                    method_coro = method(flow_instance, *args, **kwargs)
-                    if asyncio.iscoroutine(method_coro):
-                        result = await method_coro
-                    else:
-                        result = method_coro
-                    PersistenceDecorator.persist_state(flow_instance, method.__name__, actual_persistence, verbose)
-                    return result
+        if asyncio.iscoroutinefunction(method):
 
-                for attr in ["__is_start_method__", "__trigger_methods__", "__condition_type__", "__is_router__"]:
-                    if hasattr(method, attr):
-                        setattr(method_async_wrapper, attr, getattr(method, attr))
-                setattr(method_async_wrapper, "__is_flow_method__", True)
-                return cast(Callable[..., T], method_async_wrapper)
-            else:
-                @functools.wraps(method)
-                def method_sync_wrapper(flow_instance: Any, *args: Any, **kwargs: Any) -> T:
-                    result = method(flow_instance, *args, **kwargs)
-                    PersistenceDecorator.persist_state(flow_instance, method.__name__, actual_persistence, verbose)
-                    return result
+            @functools.wraps(method)
+            async def method_async_wrapper(
+                flow_instance: Any, *args: Any, **kwargs: Any
+            ) -> T:
+                method_coro = method(flow_instance, *args, **kwargs)
+                if asyncio.iscoroutine(method_coro):
+                    result = await method_coro
+                else:
+                    result = method_coro
+                PersistenceDecorator.persist_state(
+                    flow_instance, method.__name__, actual_persistence, verbose
+                )
+                return result
 
-                for attr in ["__is_start_method__", "__trigger_methods__", "__condition_type__", "__is_router__"]:
-                    if hasattr(method, attr):
-                        setattr(method_sync_wrapper, attr, getattr(method, attr))
-                setattr(method_sync_wrapper, "__is_flow_method__", True)
-                return cast(Callable[..., T], method_sync_wrapper)
+            for attr in [
+                "__is_start_method__",
+                "__trigger_methods__",
+                "__condition_type__",
+                "__is_router__",
+            ]:
+                if hasattr(method, attr):
+                    setattr(method_async_wrapper, attr, getattr(method, attr))
+            method_async_wrapper.__is_flow_method__ = True  # type: ignore[attr-defined]
+            return cast(Callable[..., T], method_async_wrapper)
+
+        @functools.wraps(method)
+        def method_sync_wrapper(flow_instance: Any, *args: Any, **kwargs: Any) -> T:
+            result = method(flow_instance, *args, **kwargs)
+            PersistenceDecorator.persist_state(
+                flow_instance, method.__name__, actual_persistence, verbose
+            )
+            return result
+
+        for attr in [
+            "__is_start_method__",
+            "__trigger_methods__",
+            "__condition_type__",
+            "__is_router__",
+        ]:
+            if hasattr(method, attr):
+                setattr(method_sync_wrapper, attr, getattr(method, attr))
+        method_sync_wrapper.__is_flow_method__ = True  # type: ignore[attr-defined]
+        return cast(Callable[..., T], method_sync_wrapper)
 
     return decorator
diff --git a/src/crewai/flow/persistence/sqlite.py b/src/crewai/flow/persistence/sqlite.py
index ee38c614d..1163d86c5 100644
--- a/src/crewai/flow/persistence/sqlite.py
+++ b/src/crewai/flow/persistence/sqlite.py
@@ -6,7 +6,7 @@ import json
 import sqlite3
 from datetime import datetime, timezone
 from pathlib import Path
-from typing import Any, Dict, Optional, Union
+from typing import Any
 
 from pydantic import BaseModel
 
@@ -23,7 +23,7 @@ class SQLiteFlowPersistence(FlowPersistence):
 
     db_path: str
 
-    def __init__(self, db_path: Optional[str] = None):
+    def __init__(self, db_path: str | None = None):
         """Initialize SQLite persistence.
 
         Args:
@@ -70,7 +70,7 @@ class SQLiteFlowPersistence(FlowPersistence):
         self,
         flow_uuid: str,
         method_name: str,
-        state_data: Union[Dict[str, Any], BaseModel],
+        state_data: dict[str, Any] | BaseModel,
     ) -> None:
         """Save the current flow state to SQLite.
 
@@ -107,7 +107,7 @@ class SQLiteFlowPersistence(FlowPersistence):
                 ),
             )
 
-    def load_state(self, flow_uuid: str) -> Optional[Dict[str, Any]]:
+    def load_state(self, flow_uuid: str) -> dict[str, Any] | None:
         """Load the most recent state for a given flow UUID.
 
         Args:
diff --git a/src/crewai/flow/types.py b/src/crewai/flow/types.py
index 8b6c9e6ad..38e3b7376 100644
--- a/src/crewai/flow/types.py
+++ b/src/crewai/flow/types.py
@@ -5,6 +5,7 @@ the Flow system.
 """
 
 from typing import Any, TypedDict
+
 from typing_extensions import NotRequired, Required
 
 
diff --git a/src/crewai/flow/utils.py b/src/crewai/flow/utils.py
index 81f3c1041..74e617bee 100644
--- a/src/crewai/flow/utils.py
+++ b/src/crewai/flow/utils.py
@@ -17,10 +17,10 @@ import ast
 import inspect
 import textwrap
 from collections import defaultdict, deque
-from typing import Any, Deque, Dict, List, Optional, Set, Union
+from typing import Any
 
 
-def get_possible_return_constants(function: Any) -> Optional[List[str]]:
+def get_possible_return_constants(function: Any) -> list[str] | None:
     try:
         source = inspect.getsource(function)
     except OSError:
@@ -58,12 +58,12 @@ def get_possible_return_constants(function: Any) -> Optional[List[str]]:
                 target = node.targets[0]
                 if isinstance(target, ast.Name):
                     var_name = target.id
-                    dict_values = []
                     # Extract string values from the dictionary
-                    for val in node.value.values:
-                        if isinstance(val, ast.Constant) and isinstance(val.value, str):
-                            dict_values.append(val.value)
-                        # If non-string, skip or just ignore
+                    dict_values = [
+                        val.value
+                        for val in node.value.values
+                        if isinstance(val, ast.Constant) and isinstance(val.value, str)
+                    ]
                     if dict_values:
                         dict_definitions[var_name] = dict_values
             self.generic_visit(node)
@@ -94,7 +94,7 @@ def get_possible_return_constants(function: Any) -> Optional[List[str]]:
     return list(return_values) if return_values else None
 
 
-def calculate_node_levels(flow: Any) -> Dict[str, int]:
+def calculate_node_levels(flow: Any) -> dict[str, int]:
     """
     Calculate the hierarchical level of each node in the flow.
 
@@ -118,10 +118,10 @@ def calculate_node_levels(flow: Any) -> Dict[str, int]:
     - Handles both OR and AND conditions for listeners
     - Processes router paths separately
     """
-    levels: Dict[str, int] = {}
-    queue: Deque[str] = deque()
-    visited: Set[str] = set()
-    pending_and_listeners: Dict[str, Set[str]] = {}
+    levels: dict[str, int] = {}
+    queue: deque[str] = deque()
+    visited: set[str] = set()
+    pending_and_listeners: dict[str, set[str]] = {}
 
     # Make all start methods at level 0
     for method_name, method in flow._methods.items():
@@ -172,7 +172,7 @@ def calculate_node_levels(flow: Any) -> Dict[str, int]:
     return levels
 
 
-def count_outgoing_edges(flow: Any) -> Dict[str, int]:
+def count_outgoing_edges(flow: Any) -> dict[str, int]:
     """
     Count the number of outgoing edges for each method in the flow.
 
@@ -197,7 +197,7 @@ def count_outgoing_edges(flow: Any) -> Dict[str, int]:
     return counts
 
 
-def build_ancestor_dict(flow: Any) -> Dict[str, Set[str]]:
+def build_ancestor_dict(flow: Any) -> dict[str, set[str]]:
     """
     Build a dictionary mapping each node to its ancestor nodes.
 
@@ -211,8 +211,8 @@ def build_ancestor_dict(flow: Any) -> Dict[str, Set[str]]:
     Dict[str, Set[str]]
         Dictionary mapping each node to a set of its ancestor nodes.
     """
-    ancestors: Dict[str, Set[str]] = {node: set() for node in flow._methods}
-    visited: Set[str] = set()
+    ancestors: dict[str, set[str]] = {node: set() for node in flow._methods}
+    visited: set[str] = set()
     for node in flow._methods:
         if node not in visited:
             dfs_ancestors(node, ancestors, visited, flow)
@@ -220,7 +220,7 @@ def build_ancestor_dict(flow: Any) -> Dict[str, Set[str]]:
 
 
 def dfs_ancestors(
-    node: str, ancestors: Dict[str, Set[str]], visited: Set[str], flow: Any
+    node: str, ancestors: dict[str, set[str]], visited: set[str], flow: Any
 ) -> None:
     """
     Perform depth-first search to build ancestor relationships.
@@ -265,7 +265,7 @@ def dfs_ancestors(
 
 
 def is_ancestor(
-    node: str, ancestor_candidate: str, ancestors: Dict[str, Set[str]]
+    node: str, ancestor_candidate: str, ancestors: dict[str, set[str]]
 ) -> bool:
     """
     Check if one node is an ancestor of another.
@@ -287,7 +287,7 @@ def is_ancestor(
     return ancestor_candidate in ancestors.get(node, set())
 
 
-def build_parent_children_dict(flow: Any) -> Dict[str, List[str]]:
+def build_parent_children_dict(flow: Any) -> dict[str, list[str]]:
     """
     Build a dictionary mapping parent nodes to their children.
 
@@ -307,7 +307,7 @@ def build_parent_children_dict(flow: Any) -> Dict[str, List[str]]:
     - Maps router methods to their paths and listeners
     - Children lists are sorted for consistent ordering
     """
-    parent_children: Dict[str, List[str]] = {}
+    parent_children: dict[str, list[str]] = {}
 
     # Map listeners to their trigger methods
     for listener_name, (_, trigger_methods) in flow._listeners.items():
@@ -332,7 +332,7 @@ def build_parent_children_dict(flow: Any) -> Dict[str, List[str]]:
 
 
 def get_child_index(
-    parent: str, child: str, parent_children: Dict[str, List[str]]
+    parent: str, child: str, parent_children: dict[str, list[str]]
 ) -> int:
     """
     Get the index of a child node in its parent's sorted children list.
@@ -364,7 +364,7 @@ def process_router_paths(flow, current, current_level, levels, queue):
         paths = flow._router_paths.get(current, [])
         for path in paths:
             for listener_name, (
-                condition_type,
+                _condition_type,
                 trigger_methods,
             ) in flow._listeners.items():
                 if path in trigger_methods:
diff --git a/src/crewai/flow/visualization_utils.py b/src/crewai/flow/visualization_utils.py
index 202fb12d8..721aef23b 100644
--- a/src/crewai/flow/visualization_utils.py
+++ b/src/crewai/flow/visualization_utils.py
@@ -17,7 +17,7 @@ Example
 
 import ast
 import inspect
-from typing import Any, Dict, List, Tuple, Union
+from typing import Any
 
 from .utils import (
     build_ancestor_dict,
@@ -56,6 +56,7 @@ def method_calls_crew(method: Any) -> bool:
 
     class CrewCallVisitor(ast.NodeVisitor):
         """AST visitor to detect .crew() method calls."""
+
         def __init__(self):
             self.found = False
 
@@ -73,8 +74,8 @@ def method_calls_crew(method: Any) -> bool:
 def add_nodes_to_network(
     net: Any,
     flow: Any,
-    node_positions: Dict[str, Tuple[float, float]],
-    node_styles: Dict[str, Dict[str, Any]]
+    node_positions: dict[str, tuple[float, float]],
+    node_styles: dict[str, dict[str, Any]],
 ) -> None:
     """
     Add nodes to the network visualization with appropriate styling.
@@ -98,6 +99,7 @@ def add_nodes_to_network(
     - Crew methods
     - Regular methods
     """
+
     def human_friendly_label(method_name):
         return method_name.replace("_", " ").title()
 
@@ -138,10 +140,10 @@ def add_nodes_to_network(
 
 def compute_positions(
     flow: Any,
-    node_levels: Dict[str, int],
+    node_levels: dict[str, int],
     y_spacing: float = 150,
-    x_spacing: float = 300
-) -> Dict[str, Tuple[float, float]]:
+    x_spacing: float = 300,
+) -> dict[str, tuple[float, float]]:
     """
     Compute the (x, y) positions for each node in the flow graph.
 
@@ -161,8 +163,8 @@ def compute_positions(
     Dict[str, Tuple[float, float]]
         Dictionary mapping node names to their (x, y) coordinates.
     """
-    level_nodes: Dict[int, List[str]] = {}
-    node_positions: Dict[str, Tuple[float, float]] = {}
+    level_nodes: dict[int, list[str]] = {}
+    node_positions: dict[str, tuple[float, float]] = {}
 
     for method_name, level in node_levels.items():
         level_nodes.setdefault(level, []).append(method_name)
@@ -180,10 +182,10 @@ def compute_positions(
 def add_edges(
     net: Any,
     flow: Any,
-    node_positions: Dict[str, Tuple[float, float]],
-    colors: Dict[str, str]
+    node_positions: dict[str, tuple[float, float]],
+    colors: dict[str, str],
 ) -> None:
-    edge_smooth: Dict[str, Union[str, float]] = {"type": "continuous"}  # Default value
+    edge_smooth: dict[str, str | float] = {"type": "continuous"}  # Default value
     """
     Add edges to the network visualization with appropriate styling.
 
@@ -269,7 +271,7 @@ def add_edges(
     for router_method_name, paths in flow._router_paths.items():
         for path in paths:
             for listener_name, (
-                condition_type,
+                _condition_type,
                 trigger_methods,
             ) in flow._listeners.items():
                 if path in trigger_methods: