diff --git a/temporalio/envconfig.py b/temporalio/envconfig.py
index 7d19881a1..95a73740d 100644
--- a/temporalio/envconfig.py
+++ b/temporalio/envconfig.py
@@ -8,7 +8,7 @@
 
 from dataclasses import dataclass, field
 from pathlib import Path
-from typing import Any, Literal, Mapping, Optional, Union, cast
+from typing import Any, Dict, Literal, Mapping, Optional, Union, cast
 
 from typing_extensions import TypeAlias, TypedDict
 
@@ -172,11 +172,11 @@ class ClientConnectConfig(TypedDict, total=False):
         Experimental API.
     """
 
-    target_host: Optional[str]
-    namespace: Optional[str]
-    api_key: Optional[str]
-    tls: Optional[Union[bool, temporalio.service.TLSConfig]]
-    rpc_metadata: Optional[Mapping[str, str]]
+    target_host: str
+    namespace: str
+    api_key: str
+    tls: Union[bool, temporalio.service.TLSConfig]
+    rpc_metadata: Mapping[str, str]
 
 
 @dataclass(frozen=True)
@@ -230,18 +230,26 @@ def to_dict(self) -> ClientConfigProfileDict:
 
     def to_client_connect_config(self) -> ClientConnectConfig:
         """Create a `ClientConnectConfig` from this profile."""
-        config: ClientConnectConfig = {}
-        if self.address:
-            config["target_host"] = self.address
-        if self.namespace:
+        if not self.address:
+            raise ValueError(
+                "Configuration profile must contain an 'address' to be used for "
+                "client connection"
+            )
+
+        # Only include non-None values
+        config: Dict[str, Any] = {}
+        config["target_host"] = self.address
+        if self.namespace is not None:
             config["namespace"] = self.namespace
-        if self.api_key:
+        if self.api_key is not None:
             config["api_key"] = self.api_key
-        if self.tls:
+        if self.tls is not None:
             config["tls"] = self.tls.to_connect_tls_config()
         if self.grpc_meta:
             config["rpc_metadata"] = self.grpc_meta
-        return config
+
+        # Cast to ClientConnectConfig - this is safe because we've only included non-None values
+        return cast(ClientConnectConfig, config)
 
     @staticmethod
     def load(
diff --git a/tests/test_envconfig.py b/tests/test_envconfig.py
index dc675dc77..33e2433f6 100644
--- a/tests/test_envconfig.py
+++ b/tests/test_envconfig.py
@@ -449,7 +449,7 @@ async def test_load_client_connect_config(client: Client, tmp_path: Path):
     config = ClientConfig.load_client_connect_config(config_file=str(config_file))
     assert config.get("target_host") == target_host
     assert config.get("namespace") == namespace
-    new_client = await Client.connect(**config)  # type: ignore
+    new_client = await Client.connect(**config)
     assert new_client.service_client.config.target_host == target_host
     assert new_client.namespace == namespace
 
@@ -462,7 +462,7 @@ async def test_load_client_connect_config(client: Client, tmp_path: Path):
     rpc_metadata = config.get("rpc_metadata")
     assert rpc_metadata
     assert "custom-header" in rpc_metadata
-    new_client = await Client.connect(**config)  # type: ignore
+    new_client = await Client.connect(**config)
     assert new_client.service_client.config.target_host == target_host
     assert new_client.namespace == "custom-namespace"
     assert (
@@ -476,7 +476,7 @@ async def test_load_client_connect_config(client: Client, tmp_path: Path):
     )
     assert config.get("target_host") == target_host
     assert config.get("namespace") == "env-namespace-override"
-    new_client = await Client.connect(**config)  # type: ignore
+    new_client = await Client.connect(**config)
     assert new_client.namespace == "env-namespace-override"
 
     # Test with env overrides disabled
@@ -487,7 +487,7 @@ async def test_load_client_connect_config(client: Client, tmp_path: Path):
     )
     assert config.get("target_host") == target_host
     assert config.get("namespace") == namespace
-    new_client = await Client.connect(**config)  # type: ignore
+    new_client = await Client.connect(**config)
     assert new_client.namespace == namespace
 
     # Test with file loading disabled (so only env is used)
@@ -500,11 +500,18 @@ async def test_load_client_connect_config(client: Client, tmp_path: Path):
     )
     assert config.get("target_host") == target_host
     assert config.get("namespace") == "env-only-namespace"
-    new_client = await Client.connect(**config)  # type: ignore
+    new_client = await Client.connect(**config)
     assert new_client.service_client.config.target_host == target_host
     assert new_client.namespace == "env-only-namespace"
 
 
+def test_to_client_connect_config_missing_address_fails():
+    """Test that to_client_connect_config raises a ValueError if address is missing."""
+    profile = ClientConfigProfile()
+    with pytest.raises(ValueError, match="must contain an 'address'"):
+        profile.to_client_connect_config()
+
+
 def test_disables_raise_error():
     """Test that providing both disable_file and disable_env raises an error."""
     with pytest.raises(RuntimeError, match="Cannot disable both"):