diff --git a/openhands/agenthub/browsing_agent/response_parser.py b/openhands/agenthub/browsing_agent/response_parser.py
index 8687016c6ad7..1caacc0e4ece 100644
--- a/openhands/agenthub/browsing_agent/response_parser.py
+++ b/openhands/agenthub/browsing_agent/response_parser.py
@@ -10,17 +10,24 @@
 
 
 class BrowsingResponseParser(ResponseParser):
-    def __init__(self):
+    def __init__(self) -> None:
         # Need to pay attention to the item order in self.action_parsers
         super().__init__()
         self.action_parsers = [BrowsingActionParserMessage()]
         self.default_parser = BrowsingActionParserBrowseInteractive()
 
-    def parse(self, response: str) -> Action:
-        action_str = self.parse_response(response)
+    def parse(
+        self, response: str | dict[str, list[dict[str, dict[str, str | None]]]]
+    ) -> Action:
+        if isinstance(response, str):
+            action_str = response
+        else:
+            action_str = self.parse_response(response)
         return self.parse_action(action_str)
 
-    def parse_response(self, response) -> str:
+    def parse_response(
+        self, response: dict[str, list[dict[str, dict[str, str | None]]]]
+    ) -> str:
         action_str = response['choices'][0]['message']['content']
         if action_str is None:
             return ''
@@ -47,9 +54,7 @@ class BrowsingActionParserMessage(ActionParser):
     - BrowseInteractiveAction(browser_actions) - unexpected response format, message back to user
     """
 
-    def __init__(
-        self,
-    ):
+    def __init__(self) -> None:
         pass
 
     def check_condition(self, action_str: str) -> bool:
@@ -69,9 +74,7 @@ class BrowsingActionParserBrowseInteractive(ActionParser):
     - BrowseInteractiveAction(browser_actions) - handle send message to user function call in BrowserGym
     """
 
-    def __init__(
-        self,
-    ):
+    def __init__(self) -> None:
         pass
 
     def check_condition(self, action_str: str) -> bool:
diff --git a/openhands/agenthub/browsing_agent/utils.py b/openhands/agenthub/browsing_agent/utils.py
index 8e67679966ae..ff08735affc8 100644
--- a/openhands/agenthub/browsing_agent/utils.py
+++ b/openhands/agenthub/browsing_agent/utils.py
@@ -5,7 +5,7 @@
 import yaml
 
 
-def yaml_parser(message):
+def yaml_parser(message: str) -> tuple[dict, bool, str]:
     """Parse a yaml message for the retry function."""
     # saves gpt-3.5 from some yaml parsing errors
     message = re.sub(r':\s*\n(?=\S|\n)', ': ', message)
@@ -22,7 +22,9 @@ def yaml_parser(message):
     return value, valid, retry_message
 
 
-def _compress_chunks(text, identifier, skip_list, split_regex='\n\n+'):
+def _compress_chunks(
+    text: str, identifier: str, skip_list: list[str], split_regex: str = '\n\n+'
+) -> tuple[dict[str, str], str]:
     """Compress a string by replacing redundant chunks by identifiers. Chunks are defined by the split_regex."""
     text_list = re.split(split_regex, text)
     text_list = [chunk.strip() for chunk in text_list]
@@ -44,7 +46,7 @@ def _compress_chunks(text, identifier, skip_list, split_regex='\n\n+'):
     return def_dict, compressed_text
 
 
-def compress_string(text):
+def compress_string(text: str) -> str:
     """Compress a string by replacing redundant paragraphs and lines with identifiers."""
     # Perform paragraph-level compression
     def_dict, compressed_text = _compress_chunks(
@@ -67,7 +69,7 @@ def compress_string(text):
     return definitions + '\n' + compressed_text
 
 
-def extract_html_tags(text, keys):
+def extract_html_tags(text: str, keys: list[str]) -> dict[str, list[str]]:
     """Extract the content within HTML tags for a list of keys.
 
     Parameters
@@ -102,7 +104,12 @@ class ParseError(Exception):
     pass
 
 
-def parse_html_tags_raise(text, keys=(), optional_keys=(), merge_multiple=False):
+def parse_html_tags_raise(
+    text: str,
+    keys: list[str] | None = None,
+    optional_keys: list[str] | None = None,
+    merge_multiple: bool = False,
+) -> dict[str, str]:
     """A version of parse_html_tags that raises an exception if the parsing is not successful."""
     content_dict, valid, retry_message = parse_html_tags(
         text, keys, optional_keys, merge_multiple=merge_multiple
@@ -112,7 +119,12 @@ def parse_html_tags_raise(text, keys=(), optional_keys=(), merge_multiple=False)
     return content_dict
 
 
-def parse_html_tags(text, keys=(), optional_keys=(), merge_multiple=False):
+def parse_html_tags(
+    text: str,
+    keys: list[str] | None = None,
+    optional_keys: list[str] | None = None,
+    merge_multiple: bool = False,
+) -> tuple[dict[str, str], bool, str]:
     """Satisfy the parse api, extracts 1 match per key and validates that all keys are present
 
     Parameters
@@ -133,9 +145,12 @@ def parse_html_tags(text, keys=(), optional_keys=(), merge_multiple=False):
     str
         A message to be displayed to the agent if the parsing was not successful.
     """
-    all_keys = tuple(keys) + tuple(optional_keys)
+    keys = keys or []
+    optional_keys = optional_keys or []
+    all_keys = list(keys) + list(optional_keys)
     content_dict = extract_html_tags(text, all_keys)
     retry_messages = []
+    result_dict: dict[str, str] = {}
 
     for key in all_keys:
         if key not in content_dict:
@@ -143,7 +158,6 @@ def parse_html_tags(text, keys=(), optional_keys=(), merge_multiple=False):
                 retry_messages.append(f'Missing the key <{key}> in the answer.')
         else:
             val = content_dict[key]
-            content_dict[key] = val[0]
             if len(val) > 1:
                 if not merge_multiple:
                     retry_messages.append(
@@ -151,8 +165,10 @@ def parse_html_tags(text, keys=(), optional_keys=(), merge_multiple=False):
                     )
                 else:
                     # merge the multiple instances
-                    content_dict[key] = '\n'.join(val)
+                    result_dict[key] = '\n'.join(val)
+            else:
+                result_dict[key] = val[0]
 
     valid = len(retry_messages) == 0
     retry_message = '\n'.join(retry_messages)
-    return content_dict, valid, retry_message
+    return result_dict, valid, retry_message
diff --git a/openhands/agenthub/codeact_agent/function_calling.py b/openhands/agenthub/codeact_agent/function_calling.py
index be39a1624ab5..b34c4e5153ab 100644
--- a/openhands/agenthub/codeact_agent/function_calling.py
+++ b/openhands/agenthub/codeact_agent/function_calling.py
@@ -475,8 +475,9 @@ def combine_thought(action: Action, thought: str) -> Action:
 def response_to_actions(response: ModelResponse) -> list[Action]:
     actions: list[Action] = []
     assert len(response.choices) == 1, 'Only one choice is supported for now'
-    assistant_msg = response.choices[0].message
-    if assistant_msg.tool_calls:
+    choice = response.choices[0]
+    assistant_msg = choice.message
+    if hasattr(assistant_msg, 'tool_calls') and assistant_msg.tool_calls:
         # Check if there's assistant_msg.content. If so, add it to the thought
         thought = ''
         if isinstance(assistant_msg.content, str):
@@ -592,7 +593,10 @@ def response_to_actions(response: ModelResponse) -> list[Action]:
             actions.append(action)
     else:
         actions.append(
-            MessageAction(content=assistant_msg.content, wait_for_response=True)
+            MessageAction(
+                content=str(assistant_msg.content) if assistant_msg.content else '',
+                wait_for_response=True,
+            )
         )
 
     assert len(actions) >= 1
diff --git a/openhands/agenthub/micro/agent.py b/openhands/agenthub/micro/agent.py
index 37de035c461d..baaba71ba614 100644
--- a/openhands/agenthub/micro/agent.py
+++ b/openhands/agenthub/micro/agent.py
@@ -22,7 +22,7 @@ def parse_response(orig_response: str) -> Action:
     return action_from_dict(action_dict)
 
 
-def to_json(obj, **kwargs):
+def to_json(obj: object, **kwargs: dict) -> str:
     """Serialize an object to str format"""
     return json.dumps(obj, **kwargs)
 
@@ -32,7 +32,9 @@ class MicroAgent(Agent):
     prompt = ''
     agent_definition: dict = {}
 
-    def history_to_json(self, history: list[Event], max_events: int = 20, **kwargs):
+    def history_to_json(
+        self, history: list[Event], max_events: int = 20, **kwargs: dict
+    ) -> str:
         """
         Serialize and simplify history to str format
         """
@@ -60,7 +62,7 @@ def __init__(self, llm: LLM, config: AgentConfig):
         super().__init__(llm, config)
         if 'name' not in self.agent_definition:
             raise ValueError('Agent definition must contain a name')
-        self.prompt_template = Environment(loader=BaseLoader).from_string(self.prompt)
+        self.prompt_template = Environment(loader=BaseLoader()).from_string(self.prompt)
         self.delegates = all_microagents.copy()
         del self.delegates[self.agent_definition['name']]
 
@@ -74,7 +76,7 @@ def step(self, state: State) -> Action:
             delegates=self.delegates,
             latest_user_message=last_user_message,
         )
-        content = [TextContent(text=prompt)]
+        content: list[TextContent | ImageContent] = [TextContent(text=prompt)]
         if self.llm.vision_is_active() and last_image_urls:
             content.append(ImageContent(image_urls=last_image_urls))
         message = Message(role='user', content=content)
diff --git a/openhands/agenthub/visualbrowsing_agent/visualbrowsing_agent.py b/openhands/agenthub/visualbrowsing_agent/visualbrowsing_agent.py
index 76bc8ba42726..0a154190d72b 100644
--- a/openhands/agenthub/visualbrowsing_agent/visualbrowsing_agent.py
+++ b/openhands/agenthub/visualbrowsing_agent/visualbrowsing_agent.py
@@ -29,7 +29,9 @@ def get_error_prefix(obs: BrowserOutputObservation) -> str:
     return f'## Error from previous action:\n{obs.last_browser_action_error}\n'
 
 
-def create_goal_prompt(goal: str, image_urls: list[str] | None):
+def create_goal_prompt(
+    goal: str, image_urls: list[str] | None
+) -> tuple[str, list[str]]:
     goal_txt: str = f"""\
 # Instructions
 Review the current state of the page and all other information to find the best possible next action to accomplish your goal. Your answer will be interpreted and executed by a program, make sure to follow the formatting instructions.
@@ -52,7 +54,7 @@ def create_observation_prompt(
     focused_element: str,
     error_prefix: str,
     som_screenshot: str | None,
-):
+) -> tuple[str, str | None]:
     txt_observation = f"""
 # Observation of current step:
 {tabs}{axtree_txt}{focused_element}{error_prefix}
@@ -273,7 +275,9 @@ def step(self, state: State) -> Action:
         observation_txt, som_screenshot = create_observation_prompt(
             cur_axtree_txt, tabs, focused_element, error_prefix, set_of_marks
         )
-        human_prompt = [TextContent(type='text', text=goal_txt)]
+        human_prompt: list[TextContent | ImageContent] = [
+            TextContent(type='text', text=goal_txt)
+        ]
         if len(goal_images) > 0:
             human_prompt.append(ImageContent(image_urls=goal_images))
         human_prompt.append(TextContent(type='text', text=observation_txt))
diff --git a/openhands/runtime/builder/docker.py b/openhands/runtime/builder/docker.py
index dbbea66daed0..4c2c13f90f04 100644
--- a/openhands/runtime/builder/docker.py
+++ b/openhands/runtime/builder/docker.py
@@ -168,10 +168,12 @@ def build(
                 )
 
         except subprocess.CalledProcessError as e:
-            logger.error(f'Image build failed:\n{e}') # TODO: {e} is empty
+            logger.error(f'Image build failed:\n{e}')  # TODO: {e} is empty
             logger.error(f'Command output:\n{e.output}')
             if self.rolling_logger.is_enabled():
-                logger.error("Docker build output:\n" + self.rolling_logger.all_lines) # Show the error
+                logger.error(
+                    'Docker build output:\n' + self.rolling_logger.all_lines
+                )  # Show the error
             raise
 
         except subprocess.TimeoutExpired:
diff --git a/openhands/runtime/impl/modal/modal_runtime.py b/openhands/runtime/impl/modal/modal_runtime.py
index 5d8073cf1c1d..5678a87bb17a 100644
--- a/openhands/runtime/impl/modal/modal_runtime.py
+++ b/openhands/runtime/impl/modal/modal_runtime.py
@@ -270,7 +270,10 @@ def vscode_url(self) -> str | None:
 
         tunnel = self.sandbox.tunnels()[self._vscode_port]
         tunnel_url = tunnel.url
-        self._vscode_url = tunnel_url + f'/?tkn={token}&folder={self.config.workspace_mount_path_in_sandbox}'
+        self._vscode_url = (
+            tunnel_url
+            + f'/?tkn={token}&folder={self.config.workspace_mount_path_in_sandbox}'
+        )
 
         self.log(
             'debug',
diff --git a/openhands/runtime/utils/vscode-extensions/hello-world/extension.js b/openhands/runtime/utils/vscode-extensions/hello-world/extension.js
index 57e06488b68c..ae119fe5f8db 100644
--- a/openhands/runtime/utils/vscode-extensions/hello-world/extension.js
+++ b/openhands/runtime/utils/vscode-extensions/hello-world/extension.js
@@ -13,4 +13,4 @@ function deactivate() {}
 module.exports = {
     activate,
     deactivate
-}
\ No newline at end of file
+}
diff --git a/openhands/runtime/utils/vscode-extensions/hello-world/package.json b/openhands/runtime/utils/vscode-extensions/hello-world/package.json
index 5c057853d69c..90ed7d7cde9d 100644
--- a/openhands/runtime/utils/vscode-extensions/hello-world/package.json
+++ b/openhands/runtime/utils/vscode-extensions/hello-world/package.json
@@ -20,4 +20,4 @@
             "title": "Hello World from OpenHands"
         }]
     }
-}
\ No newline at end of file
+}
diff --git a/openhands/server/routes/manage_conversations.py b/openhands/server/routes/manage_conversations.py
index 7711cbb9e824..5661d213821d 100644
--- a/openhands/server/routes/manage_conversations.py
+++ b/openhands/server/routes/manage_conversations.py
@@ -189,19 +189,20 @@ async def search_conversations(
         config, get_user_id(request)
     )
     conversation_metadata_result_set = await conversation_store.search(page_id, limit)
-    
+
     # Filter out conversations older than max_age
     now = datetime.now(timezone.utc)
     max_age = config.conversation_max_age_seconds
     filtered_results = [
-        conversation for conversation in conversation_metadata_result_set.results
-        if hasattr(conversation, 'created_at') and 
-        (now - conversation.created_at.replace(tzinfo=timezone.utc)).total_seconds() <= max_age
+        conversation
+        for conversation in conversation_metadata_result_set.results
+        if hasattr(conversation, 'created_at')
+        and (now - conversation.created_at.replace(tzinfo=timezone.utc)).total_seconds()
+        <= max_age
     ]
-    
+
     conversation_ids = set(
-        conversation.conversation_id
-        for conversation in filtered_results
+        conversation.conversation_id for conversation in filtered_results
     )
     running_conversations = await conversation_manager.get_running_agent_loops(
         get_user_id(request), set(conversation_ids)