diff --git a/frontend/__tests__/components/chat/chat-interface.test.tsx b/frontend/__tests__/components/chat/chat-interface.test.tsx
index 69c67406b6..5b48db05eb 100644
--- a/frontend/__tests__/components/chat/chat-interface.test.tsx
+++ b/frontend/__tests__/components/chat/chat-interface.test.tsx
@@ -45,7 +45,7 @@ describe("Empty state", () => {
   it("should render suggestions if empty", () => {
     const { store } = renderWithProviders(<ChatInterface />, {
       preloadedState: {
-        chat: { 
+        chat: {
           messages: [],
           systemMessage: {
             content: "",
@@ -76,7 +76,7 @@ describe("Empty state", () => {
   it("should render the default suggestions", () => {
     renderWithProviders(<ChatInterface />, {
       preloadedState: {
-        chat: { 
+        chat: {
           messages: [],
           systemMessage: {
             content: "",
@@ -114,7 +114,7 @@ describe("Empty state", () => {
       const user = userEvent.setup();
       const { store } = renderWithProviders(<ChatInterface />, {
         preloadedState: {
-          chat: { 
+          chat: {
             messages: [],
             systemMessage: {
               content: "",
@@ -151,7 +151,7 @@ describe("Empty state", () => {
       const user = userEvent.setup();
       const { rerender } = renderWithProviders(<ChatInterface />, {
         preloadedState: {
-          chat: { 
+          chat: {
             messages: [],
             systemMessage: {
               content: "",
diff --git a/openhands/agenthub/codeact_agent/codeact_agent.py b/openhands/agenthub/codeact_agent/codeact_agent.py
index 61ab0ac1c6..e246e77467 100644
--- a/openhands/agenthub/codeact_agent/codeact_agent.py
+++ b/openhands/agenthub/codeact_agent/codeact_agent.py
@@ -108,9 +108,7 @@ class CodeActAgent(Agent):
 
         tools = []
         if self.config.enable_cmd:
-            tools.append(
-                create_cmd_run_tool(use_short_description=use_short_tool_desc)
-            )
+            tools.append(create_cmd_run_tool(use_short_description=use_short_tool_desc))
         if self.config.enable_think:
             tools.append(ThinkTool)
         if self.config.enable_finish:
diff --git a/openhands/agenthub/codeact_agent/tools/bash.py b/openhands/agenthub/codeact_agent/tools/bash.py
index af557778d0..9adbeaa716 100644
--- a/openhands/agenthub/codeact_agent/tools/bash.py
+++ b/openhands/agenthub/codeact_agent/tools/bash.py
@@ -32,9 +32,7 @@ def create_cmd_run_tool(
     use_short_description: bool = False,
 ) -> ChatCompletionToolParam:
     description = (
-        _SHORT_BASH_DESCRIPTION
-        if use_short_description
-        else _DETAILED_BASH_DESCRIPTION
+        _SHORT_BASH_DESCRIPTION if use_short_description else _DETAILED_BASH_DESCRIPTION
     )
     return ChatCompletionToolParam(
         type='function',
diff --git a/openhands/controller/action_parser.py b/openhands/controller/action_parser.py
index fdd4f864b4..4250f46f38 100644
--- a/openhands/controller/action_parser.py
+++ b/openhands/controller/action_parser.py
@@ -1,4 +1,5 @@
 from abc import ABC, abstractmethod
+from typing import Any
 
 from openhands.events.action import Action
 
@@ -9,7 +10,7 @@ class ActionParseError(Exception):
     def __init__(self, error: str):
         self.error = error
 
-    def __str__(self):
+    def __str__(self) -> str:
         return self.error
 
 
@@ -20,16 +21,16 @@ class ResponseParser(ABC):
 
     def __init__(
         self,
-    ):
+    ) -> None:
         # Need pay attention to the item order in self.action_parsers
-        self.action_parsers = []
+        self.action_parsers: list[ActionParser] = []
 
     @abstractmethod
-    def parse(self, response: str) -> Action:
+    def parse(self, response: Any) -> Action:
         """Parses the action from the response from the LLM.
 
         Parameters:
-        - response (str): The response from the LLM.
+        - response: The response from the LLM, which can be a string or a dictionary.
 
         Returns:
         - action (Action): The action parsed from the response.
@@ -37,11 +38,11 @@ class ResponseParser(ABC):
         pass
 
     @abstractmethod
-    def parse_response(self, response) -> str:
+    def parse_response(self, response: Any) -> str:
         """Parses the action from the response from the LLM.
 
         Parameters:
-        - response (str): The response from the LLM.
+        - response: The response from the LLM, which can be a string or a dictionary.
 
         Returns:
         - action_str (str): The action str parsed from the response.
diff --git a/openhands/controller/agent.py b/openhands/controller/agent.py
index 034cacf481..ca5908adfc 100644
--- a/openhands/controller/agent.py
+++ b/openhands/controller/agent.py
@@ -1,3 +1,5 @@
+from __future__ import annotations
+
 from abc import ABC, abstractmethod
 from typing import TYPE_CHECKING, Type
 
@@ -106,11 +108,11 @@ class Agent(ABC):
             self.llm.reset()
 
     @property
-    def name(self):
+    def name(self) -> str:
         return self.__class__.__name__
 
     @classmethod
-    def register(cls, name: str, agent_cls: Type['Agent']):
+    def register(cls, name: str, agent_cls: Type['Agent']) -> None:
         """Registers an agent class in the registry.
 
         Parameters:
diff --git a/openhands/controller/agent_controller.py b/openhands/controller/agent_controller.py
index bc88f97170..795aad1909 100644
--- a/openhands/controller/agent_controller.py
+++ b/openhands/controller/agent_controller.py
@@ -1,3 +1,5 @@
+from __future__ import annotations
+
 import asyncio
 import copy
 import os
@@ -190,7 +192,7 @@ class AgentController:
             self.event_stream.add_event(system_message, EventSource.AGENT)
             logger.debug(f'System message added to event stream: {system_message}')
 
-    async def close(self, set_stop_state=True) -> None:
+    async def close(self, set_stop_state: bool = True) -> None:
         """Closes the agent controller, canceling any ongoing tasks and unsubscribing from the event stream.
 
         Note that it's fairly important that this closes properly, otherwise the state is incomplete.
@@ -242,18 +244,18 @@ class AgentController:
         extra_merged = {'session_id': self.id, **extra}
         getattr(logger, level)(message, extra=extra_merged, stacklevel=2)
 
-    def update_state_before_step(self):
+    def update_state_before_step(self) -> None:
         self.state.iteration += 1
         self.state.local_iteration += 1
 
-    async def update_state_after_step(self):
+    async def update_state_after_step(self) -> None:
         # update metrics especially for cost. Use deepcopy to avoid it being modified by agent._reset()
         self.state.local_metrics = copy.deepcopy(self.agent.llm.metrics)
 
     async def _react_to_exception(
         self,
         e: Exception,
-    ):
+    ) -> None:
         """React to an exception by setting the agent state to error and sending a status message."""
         # Store the error reason before setting the agent state
         self.state.last_error = f'{type(e).__name__}: {str(e)}'
@@ -293,7 +295,10 @@ class AgentController:
         # Set the agent state to ERROR after storing the reason
         await self.set_agent_state_to(AgentState.ERROR)
 
-    async def _step_with_exception_handling(self):
+    def step(self) -> None:
+        asyncio.create_task(self._step_with_exception_handling())
+
+    async def _step_with_exception_handling(self) -> None:
         try:
             await self._step()
         except Exception as e:
@@ -1277,7 +1282,7 @@ class AgentController:
             extra={'msg_type': 'METRICS'},
         )
 
-    def __repr__(self):
+    def __repr__(self) -> str:
         pending_action_info = '<none>'
         if (
             hasattr(self, '_pending_action_info')
@@ -1300,7 +1305,7 @@ class AgentController:
             f'_pending_action={pending_action_info})'
         )
 
-    def _is_awaiting_observation(self):
+    def _is_awaiting_observation(self) -> bool:
         events = self.event_stream.get_events(reverse=True)
         for event in events:
             if isinstance(event, AgentStateChangedObservation):
diff --git a/openhands/controller/replay.py b/openhands/controller/replay.py
index 81b17ee542..0eb8009435 100644
--- a/openhands/controller/replay.py
+++ b/openhands/controller/replay.py
@@ -1,3 +1,5 @@
+from __future__ import annotations
+
 from openhands.core.logger import openhands_logger as logger
 from openhands.events.action.action import Action
 from openhands.events.action.message import MessageAction
@@ -79,7 +81,7 @@ class ReplayManager:
         return event
 
     @staticmethod
-    def get_replay_events(trajectory) -> list[Event]:
+    def get_replay_events(trajectory: list[dict]) -> list[Event]:
         if not isinstance(trajectory, list):
             raise ValueError(
                 f'Expected a list in {trajectory}, got {type(trajectory).__name__}'
diff --git a/openhands/controller/state/state.py b/openhands/controller/state/state.py
index 71a4ce1a4a..847b513b5e 100644
--- a/openhands/controller/state/state.py
+++ b/openhands/controller/state/state.py
@@ -1,3 +1,5 @@
+from __future__ import annotations
+
 import base64
 import os
 import pickle
@@ -104,7 +106,9 @@ class State:
     extra_data: dict[str, Any] = field(default_factory=dict)
     last_error: str = ''
 
-    def save_to_session(self, sid: str, file_store: FileStore, user_id: str | None):
+    def save_to_session(
+        self, sid: str, file_store: FileStore, user_id: str | None
+    ) -> None:
         pickled = pickle.dumps(self)
         logger.debug(f'Saving state to session {sid}:{self.agent_state}')
         encoded = base64.b64encode(pickled).decode('utf-8')
@@ -165,7 +169,7 @@ class State:
         state.agent_state = AgentState.LOADING
         return state
 
-    def __getstate__(self):
+    def __getstate__(self) -> dict:
         # don't pickle history, it will be restored from the event stream
         state = self.__dict__.copy()
         state['history'] = []
@@ -177,7 +181,7 @@ class State:
 
         return state
 
-    def __setstate__(self, state):
+    def __setstate__(self, state: dict) -> None:
         self.__dict__.update(state)
 
         # make sure we always have the attribute history
diff --git a/openhands/controller/state/task.py b/openhands/controller/state/task.py
index 456ae0f0a2..e866c15a4b 100644
--- a/openhands/controller/state/task.py
+++ b/openhands/controller/state/task.py
@@ -1,3 +1,5 @@
+from __future__ import annotations
+
 from openhands.core.exceptions import (
     LLMMalformedActionError,
     TaskInvalidStateError,
@@ -21,7 +23,7 @@ STATES = [
 class Task:
     id: str
     goal: str
-    parent: 'Task | None'
+    parent: 'Task' | None
     subtasks: list['Task']
 
     def __init__(
@@ -29,8 +31,8 @@ class Task:
         parent: 'Task',
         goal: str,
         state: str = OPEN_STATE,
-        subtasks=None,  # noqa: B006
-    ):
+        subtasks: list[dict | 'Task'] | None = None,  # noqa: B006
+    ) -> None:
         """Initializes a new instance of the Task class.
 
         Args:
@@ -53,15 +55,15 @@ class Task:
             if isinstance(subtask, Task):
                 self.subtasks.append(subtask)
             else:
-                goal = subtask.get('goal')
-                state = subtask.get('state')
+                goal = str(subtask.get('goal', ''))
+                state = str(subtask.get('state', OPEN_STATE))
                 subtasks = subtask.get('subtasks')
                 logger.debug(f'Reading: {goal}, {state}, {subtasks}')
                 self.subtasks.append(Task(self, goal, state, subtasks))
 
         self.state = OPEN_STATE
 
-    def to_string(self, indent=''):
+    def to_string(self, indent: str = '') -> str:
         """Returns a string representation of the task and its subtasks.
 
         Args:
@@ -86,7 +88,7 @@ class Task:
             result += subtask.to_string(indent + '    ')
         return result
 
-    def to_dict(self):
+    def to_dict(self) -> dict:
         """Returns a dictionary representation of the task.
 
         Returns:
@@ -99,10 +101,11 @@ class Task:
             'subtasks': [t.to_dict() for t in self.subtasks],
         }
 
-    def set_state(self, state):
+    def set_state(self, state: str) -> None:
         """Sets the state of the task and its subtasks.
 
-        Args:            state: The new state of the task.
+        Args:
+            state: The new state of the task.
 
         Raises:
             TaskInvalidStateError: If the provided state is invalid.
@@ -123,7 +126,7 @@ class Task:
             if self.parent is not None:
                 self.parent.set_state(state)
 
-    def get_current_task(self) -> 'Task | None':
+    def get_current_task(self) -> 'Task' | None:
         """Retrieves the current task in progress.
 
         Returns:
@@ -155,11 +158,11 @@ class RootTask(Task):
     goal: str = ''
     parent: None = None
 
-    def __init__(self):
+    def __init__(self) -> None:
         self.subtasks = []
         self.state = OPEN_STATE
 
-    def __str__(self):
+    def __str__(self) -> str:
         """Returns a string representation of the root_task.
 
         Returns:
@@ -194,7 +197,12 @@ class RootTask(Task):
             task = task.subtasks[part]
         return task
 
-    def add_subtask(self, parent_id: str, goal: str, subtasks: list | None = None):
+    def add_subtask(
+        self,
+        parent_id: str,
+        goal: str,
+        subtasks: list[dict | Task] | None = None,
+    ) -> None:
         """Adds a subtask to a parent task.
 
         Args:
@@ -207,7 +215,7 @@ class RootTask(Task):
         child = Task(parent=parent, goal=goal, subtasks=subtasks)
         parent.subtasks.append(child)
 
-    def set_subtask_state(self, id: str, state: str):
+    def set_subtask_state(self, id: str, state: str) -> None:
         """Sets the state of a subtask.
 
         Args:
diff --git a/openhands/controller/stuck.py b/openhands/controller/stuck.py
index 0fc85d0f97..e0772a4150 100644
--- a/openhands/controller/stuck.py
+++ b/openhands/controller/stuck.py
@@ -25,7 +25,7 @@ class StuckDetector:
     def __init__(self, state: State):
         self.state = state
 
-    def is_stuck(self, headless_mode: bool = True):
+    def is_stuck(self, headless_mode: bool = True) -> bool:
         """Checks if the agent is stuck in a loop.
 
         Args:
@@ -109,7 +109,9 @@ class StuckDetector:
 
         return False
 
-    def _is_stuck_repeating_action_observation(self, last_actions, last_observations):
+    def _is_stuck_repeating_action_observation(
+        self, last_actions: list[Event], last_observations: list[Event]
+    ) -> bool:
         # scenario 1: same action, same observation
         # it takes 4 actions and 4 observations to detect a loop
         # assert len(last_actions) == 4 and len(last_observations) == 4
@@ -130,7 +132,9 @@ class StuckDetector:
 
         return False
 
-    def _is_stuck_repeating_action_error(self, last_actions, last_observations):
+    def _is_stuck_repeating_action_error(
+        self, last_actions: list[Event], last_observations: list[Event]
+    ) -> bool:
         # scenario 2: same action, errors
         # it takes 3 actions and 3 observations to detect a loop
         # check if the last three actions are the same and result in errors
@@ -155,7 +159,12 @@ class StuckDetector:
                         'SyntaxError: unterminated string literal (detected at line'
                     ):
                         if self._check_for_consistent_line_error(
-                            last_observations[:3], error_message
+                            [
+                                obs
+                                for obs in last_observations[:3]
+                                if isinstance(obs, IPythonRunCellObservation)
+                            ],
+                            error_message,
                         ):
                             logger.warning(warning)
                             return True
@@ -163,13 +172,20 @@ class StuckDetector:
                         'SyntaxError: invalid syntax. Perhaps you forgot a comma?',
                         'SyntaxError: incomplete input',
                     ) and self._check_for_consistent_invalid_syntax(
-                        last_observations[:3], error_message
+                        [
+                            obs
+                            for obs in last_observations[:3]
+                            if isinstance(obs, IPythonRunCellObservation)
+                        ],
+                        error_message,
                     ):
                         logger.warning(warning)
                         return True
         return False
 
-    def _check_for_consistent_invalid_syntax(self, observations, error_message):
+    def _check_for_consistent_invalid_syntax(
+        self, observations: list[IPythonRunCellObservation], error_message: str
+    ) -> bool:
         first_lines = []
         valid_observations = []
 
@@ -210,7 +226,9 @@ class StuckDetector:
             == 1
         )
 
-    def _check_for_consistent_line_error(self, observations, error_message):
+    def _check_for_consistent_line_error(
+        self, observations: list[IPythonRunCellObservation], error_message: str
+    ) -> bool:
         error_lines = []
 
         for obs in observations:
@@ -237,7 +255,7 @@ class StuckDetector:
         # and the 3rd-to-last line is identical across all occurrences
         return len(error_lines) == 3 and len(set(error_lines)) == 1
 
-    def _is_stuck_monologue(self, filtered_history):
+    def _is_stuck_monologue(self, filtered_history: list[Event]) -> bool:
         # scenario 3: monologue
         # check for repeated MessageActions with source=AGENT
         # see if the agent is engaged in a good old monologue, telling itself the same thing over and over
@@ -271,7 +289,9 @@ class StuckDetector:
                     return True
         return False
 
-    def _is_stuck_action_observation_pattern(self, filtered_history):
+    def _is_stuck_action_observation_pattern(
+        self, filtered_history: list[Event]
+    ) -> bool:
         # scenario 4: action, observation pattern on the last six steps
         # check if the agent repeats the same (Action, Observation)
         # every other step in the last six steps
@@ -313,7 +333,7 @@ class StuckDetector:
                 return True
         return False
 
-    def _is_stuck_context_window_error(self, filtered_history):
+    def _is_stuck_context_window_error(self, filtered_history: list[Event]) -> bool:
         """Detects if we're stuck in a loop of context window errors.
 
         This happens when we repeatedly get context window errors and try to trim,
@@ -361,7 +381,7 @@ class StuckDetector:
 
         return False
 
-    def _eq_no_pid(self, obj1, obj2):
+    def _eq_no_pid(self, obj1: Event, obj2: Event) -> bool:
         if isinstance(obj1, IPythonRunCellAction) and isinstance(
             obj2, IPythonRunCellAction
         ):
diff --git a/openhands/integrations/github/github_service.py b/openhands/integrations/github/github_service.py
index 7813c781d7..0550d9a797 100644
--- a/openhands/integrations/github/github_service.py
+++ b/openhands/integrations/github/github_service.py
@@ -46,7 +46,7 @@ class GitHubService(BaseGitService, GitService):
     @property
     def provider(self) -> str:
         return ProviderType.GITHUB.value
-    
+
     async def _get_github_headers(self) -> dict:
         """Retrieve the GH Token from settings store to construct the headers."""
         if not self.token:
diff --git a/openhands/integrations/gitlab/gitlab_service.py b/openhands/integrations/gitlab/gitlab_service.py
index c21c068f60..7efc58e639 100644
--- a/openhands/integrations/gitlab/gitlab_service.py
+++ b/openhands/integrations/gitlab/gitlab_service.py
@@ -22,7 +22,6 @@ class GitLabService(BaseGitService, GitService):
     GRAPHQL_URL = 'https://gitlab.com/api/graphql'
     token: SecretStr = SecretStr('')
     refresh = False
-    
 
     def __init__(
         self,
@@ -46,7 +45,7 @@ class GitLabService(BaseGitService, GitService):
     @property
     def provider(self) -> str:
         return ProviderType.GITLAB.value
-    
+
     async def _get_gitlab_headers(self) -> dict[str, Any]:
         """
         Retrieve the GitLab Token to construct the headers