diff --git a/.github/workflows/black.yml b/.github/workflows/black.yml
index 0a8b8e9257..c2964fb9c5 100644
--- a/.github/workflows/black.yml
+++ b/.github/workflows/black.yml
@@ -1,10 +1,10 @@
 name: Lint
 
-on: [push, pull_request]
+on: [pull_request]
 
 jobs:
   lint:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v3
-      - uses: psf/black@stable
\ No newline at end of file
+      - uses: psf/black@stable
diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index 3a0cfa4948..15b2c38247 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -1,6 +1,6 @@
 name: Run Tests
 
-on: [push, pull_request]
+on: [pull_request]
 
 permissions:
   contents: write
diff --git a/.github/workflows/type-checker.yml b/.github/workflows/type-checker.yml
new file mode 100644
index 0000000000..1501838076
--- /dev/null
+++ b/.github/workflows/type-checker.yml
@@ -0,0 +1,30 @@
+
+name: Run Type Checks
+
+on: [pull_request]
+
+permissions:
+  contents: write
+
+jobs:
+  type-checker:
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v2
+
+      - name: Setup Python
+        uses: actions/setup-python@v4
+        with:
+          python-version: '3.10'
+
+      - name: Install Requirements
+        run: |
+          sudo apt-get update &&
+          pip install poetry &&
+          poetry lock &&
+          poetry install
+
+      - name: Run type checks
+        run: poetry run pyright
diff --git a/README.md b/README.md
index 016e365bb3..0155a6e334 100644
--- a/README.md
+++ b/README.md
@@ -208,6 +208,11 @@ pre-commit install
 poetry run pytest
 ```
 
+### Running static type checks
+```bash
+poetry run pyright
+```
+
 ### Packaging
 ```bash
 poetry build
@@ -224,5 +229,3 @@ If you are interested on having access to it and hiring weekly hours with our te
 
 ## License
 CrewAI is released under the MIT License
-
-
diff --git a/poetry.lock b/poetry.lock
index 1579d38a48..fcf96d1f45 100644
--- a/poetry.lock
+++ b/poetry.lock
@@ -204,34 +204,12 @@ dev = ["freezegun (>=1.0,<2.0)", "pytest (>=6.0)", "pytest-cov"]
 
 [[package]]
 name = "black"
-version = "23.12.1"
+version = "24.1.0"
 description = "The uncompromising code formatter."
 optional = false
 python-versions = ">=3.8"
-files = [
-    {file = "black-23.12.1-cp310-cp310-macosx_10_9_x86_64.whl", hash = "sha256:e0aaf6041986767a5e0ce663c7a2f0e9eaf21e6ff87a5f95cbf3675bfd4c41d2"},
-    {file = "black-23.12.1-cp310-cp310-macosx_11_0_arm64.whl", hash = "sha256:c88b3711d12905b74206227109272673edce0cb29f27e1385f33b0163c414bba"},
-    {file = "black-23.12.1-cp310-cp310-manylinux_2_17_x86_64.manylinux2014_x86_64.whl", hash = "sha256:a920b569dc6b3472513ba6ddea21f440d4b4c699494d2e972a1753cdc25df7b0"},
-    {file = "black-23.12.1-cp310-cp310-win_amd64.whl", hash = "sha256:3fa4be75ef2a6b96ea8d92b1587dd8cb3a35c7e3d51f0738ced0781c3aa3a5a3"},
-    {file = "black-23.12.1-cp311-cp311-macosx_10_9_x86_64.whl", hash = "sha256:8d4df77958a622f9b5a4c96edb4b8c0034f8434032ab11077ec6c56ae9f384ba"},
-    {file = "black-23.12.1-cp311-cp311-macosx_11_0_arm64.whl", hash = "sha256:602cfb1196dc692424c70b6507593a2b29aac0547c1be9a1d1365f0d964c353b"},
-    {file = "black-23.12.1-cp311-cp311-manylinux_2_17_x86_64.manylinux2014_x86_64.whl", hash = "sha256:9c4352800f14be5b4864016882cdba10755bd50805c95f728011bcb47a4afd59"},
-    {file = "black-23.12.1-cp311-cp311-win_amd64.whl", hash = "sha256:0808494f2b2df923ffc5723ed3c7b096bd76341f6213989759287611e9837d50"},
-    {file = "black-23.12.1-cp312-cp312-macosx_10_9_x86_64.whl", hash = "sha256:25e57fd232a6d6ff3f4478a6fd0580838e47c93c83eaf1ccc92d4faf27112c4e"},
-    {file = "black-23.12.1-cp312-cp312-macosx_11_0_arm64.whl", hash = "sha256:2d9e13db441c509a3763a7a3d9a49ccc1b4e974a47be4e08ade2a228876500ec"},
-    {file = "black-23.12.1-cp312-cp312-manylinux_2_17_x86_64.manylinux2014_x86_64.whl", hash = "sha256:6d1bd9c210f8b109b1762ec9fd36592fdd528485aadb3f5849b2740ef17e674e"},
-    {file = "black-23.12.1-cp312-cp312-win_amd64.whl", hash = "sha256:ae76c22bde5cbb6bfd211ec343ded2163bba7883c7bc77f6b756a1049436fbb9"},
-    {file = "black-23.12.1-cp38-cp38-macosx_10_9_x86_64.whl", hash = "sha256:1fa88a0f74e50e4487477bc0bb900c6781dbddfdfa32691e780bf854c3b4a47f"},
-    {file = "black-23.12.1-cp38-cp38-macosx_11_0_arm64.whl", hash = "sha256:a4d6a9668e45ad99d2f8ec70d5c8c04ef4f32f648ef39048d010b0689832ec6d"},
-    {file = "black-23.12.1-cp38-cp38-manylinux_2_17_x86_64.manylinux2014_x86_64.whl", hash = "sha256:b18fb2ae6c4bb63eebe5be6bd869ba2f14fd0259bda7d18a46b764d8fb86298a"},
-    {file = "black-23.12.1-cp38-cp38-win_amd64.whl", hash = "sha256:c04b6d9d20e9c13f43eee8ea87d44156b8505ca8a3c878773f68b4e4812a421e"},
-    {file = "black-23.12.1-cp39-cp39-macosx_10_9_x86_64.whl", hash = "sha256:3e1b38b3135fd4c025c28c55ddfc236b05af657828a8a6abe5deec419a0b7055"},
-    {file = "black-23.12.1-cp39-cp39-macosx_11_0_arm64.whl", hash = "sha256:4f0031eaa7b921db76decd73636ef3a12c942ed367d8c3841a0739412b260a54"},
-    {file = "black-23.12.1-cp39-cp39-manylinux_2_17_x86_64.manylinux2014_x86_64.whl", hash = "sha256:97e56155c6b737854e60a9ab1c598ff2533d57e7506d97af5481141671abf3ea"},
-    {file = "black-23.12.1-cp39-cp39-win_amd64.whl", hash = "sha256:dd15245c8b68fe2b6bd0f32c1556509d11bb33aec9b5d0866dd8e2ed3dba09c2"},
-    {file = "black-23.12.1-py3-none-any.whl", hash = "sha256:78baad24af0f033958cad29731e27363183e140962595def56423e626f4bee3e"},
-    {file = "black-23.12.1.tar.gz", hash = "sha256:4ce3ef14ebe8d9509188014d96af1c456a910d5b5cbf434a09fef7e024b3d0d5"},
-]
+files = []
+develop = false
 
 [package.dependencies]
 click = ">=8.0.0"
@@ -248,6 +226,12 @@ d = ["aiohttp (>=3.7.4)", "aiohttp (>=3.7.4,!=3.9.0)"]
 jupyter = ["ipython (>=7.8.0)", "tokenize-rt (>=3.2.0)"]
 uvloop = ["uvloop (>=0.15.2)"]
 
+[package.source]
+type = "git"
+url = "https://github.com/psf/black.git"
+reference = "stable"
+resolved_reference = "0e6e46b9eb45f5a22062fe84c2c2ff46bd0d738e"
+
 [[package]]
 name = "certifi"
 version = "2023.11.17"
@@ -1549,6 +1533,24 @@ pyyaml = "*"
 [package.extras]
 extra = ["pygments (>=2.12)"]
 
+[[package]]
+name = "pyright"
+version = "1.1.333"
+description = "Command line wrapper for pyright"
+optional = false
+python-versions = ">=3.7"
+files = [
+    {file = "pyright-1.1.333-py3-none-any.whl", hash = "sha256:f0a7b7b0cac11c396b17ef3cf6c8527aca1269edaf5cf8203eed7d6dd1ef52aa"},
+    {file = "pyright-1.1.333.tar.gz", hash = "sha256:1c49b0029048120c4378f3baf6c1dcbbfb221678bb69654fe773c514430ac53c"},
+]
+
+[package.dependencies]
+nodeenv = ">=1.6.0"
+
+[package.extras]
+all = ["twine (>=3.4.1)"]
+dev = ["twine (>=3.4.1)"]
+
 [[package]]
 name = "pytest"
 version = "7.4.4"
@@ -1639,6 +1641,7 @@ files = [
     {file = "PyYAML-6.0.1-cp311-cp311-win_amd64.whl", hash = "sha256:bf07ee2fef7014951eeb99f56f39c9bb4af143d8aa3c21b1677805985307da34"},
     {file = "PyYAML-6.0.1-cp312-cp312-macosx_10_9_x86_64.whl", hash = "sha256:855fb52b0dc35af121542a76b9a84f8d1cd886ea97c84703eaa6d88e37a2ad28"},
     {file = "PyYAML-6.0.1-cp312-cp312-macosx_11_0_arm64.whl", hash = "sha256:40df9b996c2b73138957fe23a16a4f0ba614f4c0efce1e9406a184b6d07fa3a9"},
+    {file = "PyYAML-6.0.1-cp312-cp312-manylinux_2_17_aarch64.manylinux2014_aarch64.whl", hash = "sha256:a08c6f0fe150303c1c6b71ebcd7213c2858041a7e01975da3a99aed1e7a378ef"},
     {file = "PyYAML-6.0.1-cp312-cp312-manylinux_2_17_x86_64.manylinux2014_x86_64.whl", hash = "sha256:6c22bec3fbe2524cde73d7ada88f6566758a8f7227bfbf93a408a9d86bcc12a0"},
     {file = "PyYAML-6.0.1-cp312-cp312-musllinux_1_1_x86_64.whl", hash = "sha256:8d4e9c88387b0f5c7d5f281e55304de64cf7f9c0021a3525bd3b1c542da3b0e4"},
     {file = "PyYAML-6.0.1-cp312-cp312-win32.whl", hash = "sha256:d483d2cdf104e7c9fa60c544d92981f12ad66a457afae824d146093b8c294c54"},
@@ -2350,4 +2353,4 @@ testing = ["big-O", "jaraco.functools", "jaraco.itertools", "more-itertools", "p
 [metadata]
 lock-version = "2.0"
 python-versions = ">=3.9,<4.0"
-content-hash = "882fc14146aca5bf99c1c0512d74622f35c91a5b3d01d56828b564e4c554eaba"
+content-hash = "21b3fbe3c3dde7aab6f5a00eae25c97d296fda3ee095914adf2b4b789d36e19d"
diff --git a/pyproject.toml b/pyproject.toml
index 15ed4cf1b3..e51eabe67f 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -18,13 +18,15 @@ Repository = "https://github.com/joaomdmoura/crewai"
 [tool.poetry.dependencies]
 python = ">=3.9,<4.0"
 pydantic = "^2.4.2"
-langchain = "^0.1.0"
+langchain = "0.1.0"
 openai = "^1.7.1"
 langchain-openai = "^0.0.2"
+pyright = "1.1.333"
+black = {git = "https://github.com/psf/black.git", rev = "stable"}
 
 [tool.poetry.group.dev.dependencies]
 isort = "^5.13.2"
-black = "^23.12.1"
+black = "^24.1"
 autoflake = "^2.2.1"
 pre-commit = "^3.6.0"
 mkdocs-material = "^9.5.3"
@@ -33,6 +35,7 @@ mkdocs-material = "^9.5.3"
 profile = "black"
 known_first_party = ["crewai"]
 
+
 [tool.poetry.group.test.dependencies]
 pytest = "^7.4"
 pytest-vcr = "^1.0.2"
diff --git a/src/crewai/agent.py b/src/crewai/agent.py
index 111715ab01..78a6619134 100644
--- a/src/crewai/agent.py
+++ b/src/crewai/agent.py
@@ -2,10 +2,12 @@
 from typing import Any, List, Optional
 
 from langchain.agents.format_scratchpad import format_log_to_str
+from langchain.agents.agent import RunnableAgent
 from langchain.memory import ConversationSummaryMemory
 from langchain.tools.render import render_text_description
 from langchain_core.runnables.config import RunnableConfig
 from langchain_openai import ChatOpenAI
+from langchain_core.language_models import BaseLanguageModel
 from pydantic import (
     UUID4,
     BaseModel,
@@ -47,7 +49,7 @@ class Agent(BaseModel):
             tools: Tools at agents disposal
     """
 
-    __hash__ = object.__hash__
+    __hash__ = object.__hash__  # type: ignore
     _logger: Logger = PrivateAttr()
     _rpm_controller: RPMController = PrivateAttr(default=None)
     _request_within_rpm_limit: Any = PrivateAttr(default=None)
@@ -80,21 +82,19 @@ class Agent(BaseModel):
     max_iter: Optional[int] = Field(
         default=15, description="Maximum iterations for an agent to execute a task"
     )
-    agent_executor: Optional[InstanceOf[CrewAgentExecutor]] = Field(
+    agent_executor: InstanceOf[CrewAgentExecutor] = Field(
         default=None, description="An instance of the CrewAgentExecutor class."
     )
-    tools_handler: Optional[InstanceOf[ToolsHandler]] = Field(
+    tools_handler: InstanceOf[ToolsHandler] = Field(
         default=None, description="An instance of the ToolsHandler class."
     )
-    cache_handler: Optional[InstanceOf[CacheHandler]] = Field(
+    cache_handler: InstanceOf[CacheHandler] = Field(
         default=CacheHandler(), description="An instance of the CacheHandler class."
     )
-    i18n: Optional[I18N] = Field(
-        default=I18N(), description="Internationalization settings."
-    )
-    llm: Optional[Any] = Field(
+    i18n: I18N = Field(default=I18N(), description="Internationalization settings.")
+    llm: Any = Field(
         default_factory=lambda: ChatOpenAI(
-            model_name="gpt-4",
+            model="gpt-4",
         ),
         description="Language model that will run the agent.",
     )
@@ -140,6 +140,7 @@ def execute_task(
         Returns:
             Output of the agent
         """
+
         if context:
             task = self.i18n.slice("task_with_context").format(
                 task=task, context=context
@@ -203,9 +204,9 @@ def __create_agent_executor(self) -> None:
         }
 
         if self._rpm_controller:
-            executor_args[
-                "request_within_rpm_limit"
-            ] = self._rpm_controller.check_or_wait
+            executor_args["request_within_rpm_limit"] = (
+                self._rpm_controller.check_or_wait
+            )
 
         if self.memory:
             summary_memory = ConversationSummaryMemory(
@@ -234,7 +235,9 @@ def __create_agent_executor(self) -> None:
                 i18n=self.i18n,
             )
         )
-        self.agent_executor = CrewAgentExecutor(agent=inner_agent, **executor_args)
+        self.agent_executor = CrewAgentExecutor(
+            agent=RunnableAgent(runnable=inner_agent), **executor_args
+        )
 
     @staticmethod
     def __tools_names(tools) -> str:
diff --git a/src/crewai/agents/cache/cache_handler.py b/src/crewai/agents/cache/cache_handler.py
index def5684a97..84c91c4cc9 100644
--- a/src/crewai/agents/cache/cache_handler.py
+++ b/src/crewai/agents/cache/cache_handler.py
@@ -1,12 +1,10 @@
 from typing import Optional
 
-from pydantic import PrivateAttr
-
 
 class CacheHandler:
     """Callback handler for tool usage."""
 
-    _cache: PrivateAttr = {}
+    _cache: dict = {}
 
     def __init__(self):
         self._cache = {}
diff --git a/src/crewai/agents/executor.py b/src/crewai/agents/executor.py
index 61bd8feebd..d3c869a463 100644
--- a/src/crewai/agents/executor.py
+++ b/src/crewai/agents/executor.py
@@ -108,8 +108,12 @@ def _iter_next_step(
             if self._should_force_answer():
                 if isinstance(output, AgentAction):
                     output = output
-                else:
+                elif isinstance(output, CacheHit):
                     output = output.action
+                else:
+                    raise ValueError(
+                        f"Unexpected output type from agent: {type(output)}"
+                    )
                 yield self._force_answer(output)
                 return
 
diff --git a/src/crewai/agents/output_parser.py b/src/crewai/agents/output_parser.py
index 41bf0681c7..9edeb12b0d 100644
--- a/src/crewai/agents/output_parser.py
+++ b/src/crewai/agents/output_parser.py
@@ -50,7 +50,6 @@ class Config:
     i18n: I18N
 
     def parse(self, text: str) -> Union[AgentAction, AgentFinish, CacheHit]:
-        FINAL_ANSWER_ACTION in text
         regex = (
             r"Action\s*\d*\s*:[\s]*(.*?)[\s]*Action\s*\d*\s*Input\s*\d*\s*:[\s]*(.*)"
         )
diff --git a/src/crewai/agents/tools_handler.py b/src/crewai/agents/tools_handler.py
index d2f2ac568f..24a81c4256 100644
--- a/src/crewai/agents/tools_handler.py
+++ b/src/crewai/agents/tools_handler.py
@@ -10,9 +10,9 @@ class ToolsHandler(BaseCallbackHandler):
     """Callback handler for tool usage."""
 
     last_used_tool: Dict[str, Any] = {}
-    cache: CacheHandler = None
+    cache: CacheHandler
 
-    def __init__(self, cache: CacheHandler = None, **kwargs: Any):
+    def __init__(self, cache: CacheHandler, **kwargs: Any):
         """Initialize the callback handler."""
         self.cache = cache
         super().__init__(**kwargs)
diff --git a/src/crewai/crew.py b/src/crewai/crew.py
index ee2cb4947c..ded7aa7cea 100644
--- a/src/crewai/crew.py
+++ b/src/crewai/crew.py
@@ -38,12 +38,10 @@ class Crew(BaseModel):
         id: A unique identifier for the crew instance.
     """
 
-    __hash__ = object.__hash__
+    __hash__ = object.__hash__  # type: ignore
     _rpm_controller: RPMController = PrivateAttr()
     _logger: Logger = PrivateAttr()
-    _cache_handler: Optional[InstanceOf[CacheHandler]] = PrivateAttr(
-        default=CacheHandler()
-    )
+    _cache_handler: InstanceOf[CacheHandler] = PrivateAttr(default=CacheHandler())
     model_config = ConfigDict(arbitrary_types_allowed=True)
     tasks: List[Task] = Field(default_factory=list)
     agents: List[Agent] = Field(default_factory=list)
@@ -69,20 +67,20 @@ def _deny_user_set_id(cls, v: Optional[UUID4]) -> None:
                 "may_not_set_field", "The 'id' field cannot be set by the user.", {}
             )
 
-    @classmethod
     @field_validator("config", mode="before")
+    @classmethod
     def check_config_type(
         cls, v: Union[Json, Dict[str, Any]]
     ) -> Union[Json, Dict[str, Any]]:
         """Validates that the config is a valid type.
-
         Args:
             v: The config to be validated.
-
         Returns:
             The config if it is valid.
         """
-        return json.loads(v) if isinstance(v, Json) else v
+
+        # TODO: Improve typing
+        return json.loads(v) if isinstance(v, Json) else v  # type: ignore
 
     @model_validator(mode="after")
     def set_private_attrs(self) -> "Crew":
@@ -112,6 +110,8 @@ def check_config(self):
         return self
 
     def _setup_from_config(self):
+        assert self.config is not None, "Config should not be None."
+
         """Initializes agents and tasks from the provided config."""
         if not self.config.get("agents") or not self.config.get("tasks"):
             raise PydanticCustomError(
@@ -143,19 +143,24 @@ def kickoff(self) -> str:
 
         if self.process == Process.sequential:
             return self._sequential_loop()
+        else:
+            raise NotImplementedError(
+                f"The process '{self.process}' is not implemented yet."
+            )
 
     def _sequential_loop(self) -> str:
         """Executes tasks sequentially and returns the final output."""
-        task_output = None
+        task_output = ""
         for task in self.tasks:
             self._prepare_and_execute_task(task)
             task_output = task.execute(task_output)
-            self._logger.log(
-                "debug", f"[{task.agent.role}] Task output: {task_output}\n\n"
-            )
+
+            role = task.agent.role if task.agent is not None else "None"
+            self._logger.log("debug", f"[{role}] Task output: {task_output}\n\n")
 
         if self.max_rpm:
             self._rpm_controller.stop_rpm_counter()
+
         return task_output
 
     def _prepare_and_execute_task(self, task: Task) -> None:
@@ -164,8 +169,9 @@ def _prepare_and_execute_task(self, task: Task) -> None:
         Args:
             task: The task to be executed.
         """
-        if task.agent.allow_delegation:
+        if task.agent is not None and task.agent.allow_delegation:
             task.tools += AgentTools(agents=self.agents).tools()
 
-        self._logger.log("debug", f"Working Agent: {task.agent.role}")
+        role = task.agent.role if task.agent is not None else "None"
+        self._logger.log("debug", f"Working Agent: {role}")
         self._logger.log("info", f"Starting Task: {task.description}")
diff --git a/src/crewai/task.py b/src/crewai/task.py
index 8a15588aae..d0d070805a 100644
--- a/src/crewai/task.py
+++ b/src/crewai/task.py
@@ -12,7 +12,7 @@
 class Task(BaseModel):
     """Class that represent a task to be executed."""
 
-    __hash__ = object.__hash__
+    __hash__ = object.__hash__  # type: ignore
     i18n: I18N = I18N()
     description: str = Field(description="Description of the actual task.")
     agent: Optional[Agent] = Field(
@@ -20,7 +20,7 @@ class Task(BaseModel):
     )
     tools: List[Any] = Field(
         default_factory=list,
-        description="Tools the agent are limited to use for this task.",
+        description="Tools the agent is limited to use for this task.",
     )
     expected_output: str = Field(
         description="Clear definition of expected output for the task.",
@@ -46,7 +46,7 @@ def _deny_user_set_id(cls, v: Optional[UUID4]) -> None:
     @model_validator(mode="after")
     def check_tools(self):
         """Check if the tools are set."""
-        if not self.tools and (self.agent and self.agent.tools):
+        if not self.tools and self.agent and self.agent.tools:
             self.tools.extend(self.agent.tools)
         return self
 
diff --git a/src/crewai/tools/agent_tools.py b/src/crewai/tools/agent_tools.py
index 56c19ae3aa..9349cc4a07 100644
--- a/src/crewai/tools/agent_tools.py
+++ b/src/crewai/tools/agent_tools.py
@@ -1,4 +1,4 @@
-from typing import List, Optional
+from typing import List
 
 from langchain.tools import Tool
 from pydantic import BaseModel, Field
@@ -11,9 +11,7 @@ class AgentTools(BaseModel):
     """Default tools around agent delegation"""
 
     agents: List[Agent] = Field(description="List of agents in this crew.")
-    i18n: Optional[I18N] = Field(
-        default=I18N(), description="Internationalization settings."
-    )
+    i18n: I18N = Field(default=I18N(), description="Internationalization settings.")
 
     def tools(self):
         return [
diff --git a/src/crewai/utilities/i18n.py b/src/crewai/utilities/i18n.py
index 9762bb2ea0..6dfcd688f2 100644
--- a/src/crewai/utilities/i18n.py
+++ b/src/crewai/utilities/i18n.py
@@ -6,7 +6,7 @@
 
 
 class I18N(BaseModel):
-    _translations: Optional[Dict[str, str]] = PrivateAttr()
+    _translations: Dict[str, Dict[str, str]] = PrivateAttr()
     language: Optional[str] = Field(
         default="en",
         description="Language used to load translations",
@@ -25,10 +25,14 @@ def load_translation(self) -> "I18N":
                 self._translations = json.load(f)
         except FileNotFoundError:
             raise ValidationError(
-                f"Trasnlation file for language '{self.language}' not found."
+                f"Translation file for language '{self.language}' not found."
             )
         except json.JSONDecodeError:
             raise ValidationError(f"Error decoding JSON from the prompts file.")
+
+        if not self._translations:
+            self._translations = {}
+
         return self
 
     def slice(self, slice: str) -> str:
@@ -40,8 +44,8 @@ def errors(self, error: str) -> str:
     def tools(self, error: str) -> str:
         return self.retrieve("tools", error)
 
-    def retrieve(self, kind, key):
+    def retrieve(self, kind, key) -> str:
         try:
-            return self._translations[kind].get(key)
+            return self._translations[kind][key]
         except:
             raise ValidationError(f"Translation for '{kind}':'{key}'  not found.")
diff --git a/src/crewai/utilities/prompts.py b/src/crewai/utilities/prompts.py
index 60991e7222..4647543316 100644
--- a/src/crewai/utilities/prompts.py
+++ b/src/crewai/utilities/prompts.py
@@ -1,6 +1,6 @@
 from typing import ClassVar
 
-from langchain.prompts import PromptTemplate
+from langchain.prompts import PromptTemplate, BasePromptTemplate
 from pydantic import BaseModel, Field
 
 from crewai.utilities import I18N
@@ -13,19 +13,19 @@ class Prompts(BaseModel):
 
     SCRATCHPAD_SLICE: ClassVar[str] = "\n{agent_scratchpad}"
 
-    def task_execution_with_memory(self) -> str:
+    def task_execution_with_memory(self) -> BasePromptTemplate:
         """Generate a prompt for task execution with memory components."""
         return self._build_prompt(["role_playing", "tools", "memory", "task"])
 
-    def task_execution_without_tools(self) -> str:
+    def task_execution_without_tools(self) -> BasePromptTemplate:
         """Generate a prompt for task execution without tools components."""
         return self._build_prompt(["role_playing", "task"])
 
-    def task_execution(self) -> str:
+    def task_execution(self) -> BasePromptTemplate:
         """Generate a standard prompt for task execution."""
         return self._build_prompt(["role_playing", "tools", "task"])
 
-    def _build_prompt(self, components: [str]) -> str:
+    def _build_prompt(self, components: list[str]) -> BasePromptTemplate:
         """Constructs a prompt string from specified components."""
         prompt_parts = [self.i18n.slice(component) for component in components]
         prompt_parts.append(self.SCRATCHPAD_SLICE)
diff --git a/src/crewai/utilities/rpm_controller.py b/src/crewai/utilities/rpm_controller.py
index 1bf5f27453..4faa7d3ce5 100644
--- a/src/crewai/utilities/rpm_controller.py
+++ b/src/crewai/utilities/rpm_controller.py
@@ -12,7 +12,7 @@ class RPMController(BaseModel):
     max_rpm: Union[int, None] = Field(default=None)
     logger: Logger = Field(default=None)
     _current_rpm: int = PrivateAttr(default=0)
-    _timer: threading.Timer = PrivateAttr(default=None)
+    _timer: threading.Timer | None = PrivateAttr(default=None)
     _lock: threading.Lock = PrivateAttr(default=None)
 
     @model_validator(mode="after")
diff --git a/tests/task_test.py b/tests/task_test.py
index 8d286b32f2..f1793feb10 100644
--- a/tests/task_test.py
+++ b/tests/task_test.py
@@ -1,6 +1,5 @@
 """Test Agent creation and execution basic functionality."""
 
-
 from crewai.agent import Agent
 from crewai.task import Task
 
@@ -51,7 +50,6 @@ def fake_task_tool() -> None:
         description="Give me a list of 5 interesting ideas to explore for na article, what makes them unique and interesting.",
         agent=researcher,
         tools=[fake_task_tool],
-        allow_delegation=False,
     )
 
     assert task.tools == [fake_task_tool]
@@ -69,7 +67,6 @@ def test_task_prompt_includes_expected_output():
         description="Give me a list of 5 interesting ideas to explore for na article, what makes them unique and interesting.",
         expected_output="Bullet point list of 5 interesting ideas.",
         agent=researcher,
-        allow_delegation=False,
     )
 
     from unittest.mock import patch