diff --git a/examples/alpha/create_workflow.py b/examples/alpha/create_workflow.py
index 669d7a7..57d0ddc 100644
--- a/examples/alpha/create_workflow.py
+++ b/examples/alpha/create_workflow.py
@@ -2,7 +2,7 @@
 
 import opengradient as og
 
-alpha = og.Alpha(private_key=os.environ.get("OG_PRIVATE_KEY"))
+alpha = og.Alpha(private_key=os.environ["OG_PRIVATE_KEY"])
 
 # Define model input
 input_query = og.HistoricalInputQuery(
diff --git a/examples/alpha/run_embeddings_model.py b/examples/alpha/run_embeddings_model.py
index 11832d6..bd95278 100644
--- a/examples/alpha/run_embeddings_model.py
+++ b/examples/alpha/run_embeddings_model.py
@@ -2,7 +2,7 @@
 
 import opengradient as og
 
-alpha = og.Alpha(private_key=os.environ.get("OG_PRIVATE_KEY"))
+alpha = og.Alpha(private_key=os.environ["OG_PRIVATE_KEY"])
 
 queries = [
     "how much protein should a female eat",
diff --git a/examples/alpha/run_inference.py b/examples/alpha/run_inference.py
index d23ed03..e5ad69f 100644
--- a/examples/alpha/run_inference.py
+++ b/examples/alpha/run_inference.py
@@ -2,7 +2,7 @@
 
 import opengradient as og
 
-alpha = og.Alpha(private_key=os.environ.get("OG_PRIVATE_KEY"))
+alpha = og.Alpha(private_key=os.environ["OG_PRIVATE_KEY"])
 
 inference_result = alpha.infer(
     model_cid="hJD2Ja3akZFt1A2LT-D_1oxOCz_OtuGYw4V9eE1m39M",
diff --git a/examples/alpha/use_workflow.py b/examples/alpha/use_workflow.py
index a86ffda..390cb2f 100644
--- a/examples/alpha/use_workflow.py
+++ b/examples/alpha/use_workflow.py
@@ -2,7 +2,7 @@
 
 import opengradient as og
 
-alpha = og.Alpha(private_key=os.environ.get("OG_PRIVATE_KEY"))
+alpha = og.Alpha(private_key=os.environ["OG_PRIVATE_KEY"])
 
 model_output = alpha.read_workflow_result(
     # This is the workflow contract address that you previously deployed
diff --git a/examples/langchain_react_agent.py b/examples/langchain_react_agent.py
index ebd7c03..9ca5faa 100644
--- a/examples/langchain_react_agent.py
+++ b/examples/langchain_react_agent.py
@@ -15,7 +15,7 @@
 
 import opengradient as og
 
-private_key = os.environ.get("OG_PRIVATE_KEY")
+private_key = os.environ["OG_PRIVATE_KEY"]
 
 # One-time Permit2 approval for OPG spending (idempotent)
 llm_client = og.LLM(private_key=private_key)
diff --git a/examples/twins_chat.py b/examples/twins_chat.py
index 786c9c4..5485732 100644
--- a/examples/twins_chat.py
+++ b/examples/twins_chat.py
@@ -5,7 +5,7 @@
 
 import opengradient as og
 
-twins = og.Twins(api_key=os.environ.get("TWINS_API_KEY"))
+twins = og.Twins(api_key=os.environ["TWINS_API_KEY"])
 
 # Chat with Elon Musk
 print("--------------------------------")
@@ -18,7 +18,7 @@
     messages=[{"role": "user", "content": "What do you think about AI?"}],
     max_tokens=1000,
 )
-print(f"Elon: {elon.chat_output['content']}")
+print(f"Elon: {elon.chat_output['content'] if elon.chat_output else None}")
 
 # Chat with Donald Trump
 print("--------------------------------")
@@ -31,4 +31,4 @@
     messages=[{"role": "user", "content": "What's your plan for America?"}],
     max_tokens=1000,
 )
-print(f"Trump: {trump.chat_output['content']}")
+print(f"Trump: {trump.chat_output['content'] if trump.chat_output else None}")
diff --git a/src/opengradient/client/_utils.py b/src/opengradient/client/_utils.py
index 7e73011..5e2938a 100644
--- a/src/opengradient/client/_utils.py
+++ b/src/opengradient/client/_utils.py
@@ -20,7 +20,8 @@ def get_abi(abi_name: str) -> dict:
     """Returns the ABI for the requested contract."""
     abi_path = _ABI_DIR / abi_name
     with open(abi_path, "r") as f:
-        return json.load(f)
+        result: dict = json.load(f)
+        return result
 
 
 def get_bin(bin_name: str) -> str:
diff --git a/src/opengradient/client/alpha.py b/src/opengradient/client/alpha.py
index 1a31e33..a4e633e 100644
--- a/src/opengradient/client/alpha.py
+++ b/src/opengradient/client/alpha.py
@@ -18,7 +18,7 @@
 from web3.logs import DISCARD
 
 from ..types import HistoricalInputQuery, InferenceMode, InferenceResult, ModelOutput, SchedulerParams
-from ._conversions import convert_array_to_model_output, convert_to_model_input, convert_to_model_output
+from ._conversions import convert_array_to_model_output, convert_to_model_input, convert_to_model_output  # type: ignore[attr-defined]
 from ._utils import get_abi, get_bin, run_with_retry
 
 DEFAULT_RPC_URL = "https://ogevmdevnet.opengradient.ai"
@@ -57,8 +57,8 @@ def __init__(
         self._wallet_account: LocalAccount = self._blockchain.eth.account.from_key(private_key)
         self._inference_hub_contract_address = inference_contract_address
         self._api_url = api_url
-        self._inference_abi = None
-        self._precompile_abi = None
+        self._inference_abi: Optional[dict] = None
+        self._precompile_abi: Optional[dict] = None
 
     @property
     def inference_abi(self) -> dict:
@@ -98,8 +98,12 @@ def infer(
         """
 
         def execute_transaction():
-            contract = self._blockchain.eth.contract(address=self._inference_hub_contract_address, abi=self.inference_abi)
-            precompile_contract = self._blockchain.eth.contract(address=PRECOMPILE_CONTRACT_ADDRESS, abi=self.precompile_abi)
+            contract = self._blockchain.eth.contract(
+                address=Web3.to_checksum_address(self._inference_hub_contract_address), abi=self.inference_abi
+            )
+            precompile_contract = self._blockchain.eth.contract(
+                address=Web3.to_checksum_address(PRECOMPILE_CONTRACT_ADDRESS), abi=self.precompile_abi
+            )
 
             inference_mode_uint8 = inference_mode.value
             converted_model_input = convert_to_model_input(model_input)
@@ -122,7 +126,8 @@ def execute_transaction():
 
             return InferenceResult(tx_hash.hex(), model_output)
 
-        return run_with_retry(execute_transaction, max_retries)
+        result: InferenceResult = run_with_retry(execute_transaction, max_retries)
+        return result
 
     def _send_tx_with_revert_handling(self, run_function):
         """
@@ -161,7 +166,7 @@ def _send_tx_with_revert_handling(self, run_function):
             }
         )
 
-        signed_tx = self._wallet_account.sign_transaction(transaction)
+        signed_tx = self._wallet_account.sign_transaction(transaction)  # type: ignore[arg-type]
         tx_hash = self._blockchain.eth.send_raw_transaction(signed_tx.raw_transaction)
         tx_receipt = self._blockchain.eth.wait_for_transaction_receipt(tx_hash, timeout=INFERENCE_TX_TIMEOUT)
 
@@ -176,7 +181,7 @@ def _send_tx_with_revert_handling(self, run_function):
 
         return tx_hash, tx_receipt
 
-    def _get_inference_result_from_node(self, inference_id: str, inference_mode: InferenceMode) -> Dict:
+    def _get_inference_result_from_node(self, inference_id: str, inference_mode: InferenceMode) -> Optional[Dict]:
         """
         Get the inference result from node.
 
@@ -317,7 +322,7 @@ def deploy_transaction():
 
             return tx_receipt.contractAddress
 
-        contract_address = run_with_retry(deploy_transaction)
+        contract_address: str = run_with_retry(deploy_transaction)
 
         if scheduler_params:
             self._register_with_scheduler(contract_address, scheduler_params)
@@ -343,7 +348,7 @@ def _register_with_scheduler(self, contract_address: str, scheduler_params: Sche
 
         # Scheduler contract address
         scheduler_address = DEFAULT_SCHEDULER_ADDRESS
-        scheduler_contract = self._blockchain.eth.contract(address=scheduler_address, abi=scheduler_abi)
+        scheduler_contract = self._blockchain.eth.contract(address=Web3.to_checksum_address(scheduler_address), abi=scheduler_abi)
 
         try:
             # Register the workflow with the scheduler
@@ -359,7 +364,7 @@ def _register_with_scheduler(self, contract_address: str, scheduler_params: Sche
                 }
             )
 
-            signed_scheduler_tx = self._wallet_account.sign_transaction(scheduler_tx)
+            signed_scheduler_tx = self._wallet_account.sign_transaction(scheduler_tx)  # type: ignore[arg-type]
             scheduler_tx_hash = self._blockchain.eth.send_raw_transaction(signed_scheduler_tx.raw_transaction)
             self._blockchain.eth.wait_for_transaction_receipt(scheduler_tx_hash, timeout=REGULAR_TX_TIMEOUT)
         except Exception as e:
@@ -388,7 +393,8 @@ def read_workflow_result(self, contract_address: str) -> ModelOutput:
         # Get the result
         result = contract.functions.getInferenceResult().call()
 
-        return convert_array_to_model_output(result)
+        output: ModelOutput = convert_array_to_model_output(result)
+        return output
 
     def run_workflow(self, contract_address: str) -> ModelOutput:
         """
@@ -423,17 +429,18 @@ def run_workflow(self, contract_address: str) -> ModelOutput:
             }
         )
 
-        signed_txn = self._wallet_account.sign_transaction(transaction)
+        signed_txn = self._wallet_account.sign_transaction(transaction)  # type: ignore[arg-type]
         tx_hash = self._blockchain.eth.send_raw_transaction(signed_txn.raw_transaction)
         tx_receipt = self._blockchain.eth.wait_for_transaction_receipt(tx_hash, timeout=INFERENCE_TX_TIMEOUT)
 
-        if tx_receipt.status == 0:
+        if tx_receipt["status"] == 0:
             raise ContractLogicError(f"Run transaction failed. Receipt: {tx_receipt}")
 
         # Get the inference result from the contract
         result = contract.functions.getInferenceResult().call()
 
-        return convert_array_to_model_output(result)
+        run_output: ModelOutput = convert_array_to_model_output(result)
+        return run_output
 
     def read_workflow_history(self, contract_address: str, num_results: int) -> List[ModelOutput]:
         """
diff --git a/src/opengradient/client/model_hub.py b/src/opengradient/client/model_hub.py
index 35f0b72..d8f5c92 100644
--- a/src/opengradient/client/model_hub.py
+++ b/src/opengradient/client/model_hub.py
@@ -165,10 +165,10 @@ def upload(self, model_path: str, model_name: str, version: str) -> FileUploadRe
                     else:
                         raise RuntimeError("Empty or null response content received")
                 elif response.status_code == 500:
-                    raise RuntimeError("Internal server error occurred", status_code=500)
+                    raise RuntimeError(f"Internal server error occurred (status_code=500)")
                 else:
                     error_message = response.json().get("detail", "Unknown error occurred")
-                    raise RuntimeError(f"Upload failed: {error_message}", status_code=response.status_code)
+                    raise RuntimeError(f"Upload failed: {error_message} (status_code={response.status_code})")
 
         except requests.RequestException as e:
             raise RuntimeError(f"Upload failed: {str(e)}")
@@ -200,7 +200,8 @@ def list_files(self, model_name: str, version: str) -> List[Dict]:
         try:
             response = requests.get(url, headers=headers)
             response.raise_for_status()
-            return response.json()
+            result: list[dict] = response.json()
+            return result
 
         except requests.RequestException as e:
             raise RuntimeError(f"File listing failed: {str(e)}")
diff --git a/src/opengradient/client/opg_token.py b/src/opengradient/client/opg_token.py
index 87d3867..22cc8bc 100644
--- a/src/opengradient/client/opg_token.py
+++ b/src/opengradient/client/opg_token.py
@@ -100,11 +100,11 @@ def ensure_opg_approval(wallet_account: LocalAccount, opg_amount: float) -> Perm
             }
         )
 
-        signed = wallet_account.sign_transaction(tx)
+        signed = wallet_account.sign_transaction(tx)  # type: ignore[arg-type]
         tx_hash = w3.eth.send_raw_transaction(signed.raw_transaction)
         receipt = w3.eth.wait_for_transaction_receipt(tx_hash, timeout=120)
 
-        if receipt.status != 1:
+        if receipt.status != 1:  # type: ignore[attr-defined]
             raise RuntimeError(f"Permit2 approval transaction reverted: {tx_hash.hex()}")
 
         allowance_after = token.functions.allowance(owner, spender).call()
diff --git a/src/opengradient/client/twins.py b/src/opengradient/client/twins.py
index 55adeaf..94bafcc 100644
--- a/src/opengradient/client/twins.py
+++ b/src/opengradient/client/twins.py
@@ -87,9 +87,6 @@ def chat(
         except RuntimeError:
             raise
         except httpx.HTTPStatusError as e:
-            raise RuntimeError(
-                f"Twins chat request failed: {e.response.status_code} {e.response.text}",
-                status_code=e.response.status_code,
-            )
+            raise RuntimeError(f"Twins chat request failed: {e.response.status_code} {e.response.text}")
         except Exception as e:
             raise RuntimeError(f"Twins chat request failed: {str(e)}")
diff --git a/src/opengradient/py.typed b/src/opengradient/py.typed
new file mode 100644
index 0000000..e69de29
diff --git a/src/opengradient/types.py b/src/opengradient/types.py
index 492bed4..1f7ec75 100644
--- a/src/opengradient/types.py
+++ b/src/opengradient/types.py
@@ -324,7 +324,7 @@ def __next__(self) -> StreamChunk:
 
         while True:
             try:
-                line = next(self._iterator)
+                line = next(self._iterator)  # type: ignore[arg-type]
             except StopIteration:
                 raise
 
@@ -355,7 +355,7 @@ async def __anext__(self) -> StreamChunk:
 
         while True:
             try:
-                line = await self._iterator.__anext__()
+                line = await self._iterator.__anext__()  # type: ignore[union-attr]
             except StopAsyncIteration:
                 raise