diff --git a/src/datacustomcode/__init__.py b/src/datacustomcode/__init__.py
index fdb0679..2662e74 100644
--- a/src/datacustomcode/__init__.py
+++ b/src/datacustomcode/__init__.py
@@ -17,7 +17,9 @@
 from datacustomcode.credentials import AuthType, Credentials
 from datacustomcode.io.reader.query_api import QueryAPIDataCloudReader
 from datacustomcode.io.writer.print import PrintDataCloudWriter
-from datacustomcode.proxy.client.local_proxy_client import LocalProxyClientProvider
+from datacustomcode.proxy.client.LocalProxyClientProvider import (
+    LocalProxyClientProvider,
+)
 
 __all__ = [
     "AuthType",
diff --git a/src/datacustomcode/client.py b/src/datacustomcode/client.py
index d1a1138..01aed31 100644
--- a/src/datacustomcode/client.py
+++ b/src/datacustomcode/client.py
@@ -107,8 +107,9 @@ class Client:
     _reader: BaseDataCloudReader
     _writer: BaseDataCloudWriter
     _file: DefaultFindFilePath
-    _proxy: BaseProxyClient
+    _proxy: Optional[BaseProxyClient]
     _data_layer_history: dict[DataCloudObjectType, set[str]]
+    _code_type: str
 
     def __new__(
         cls,
@@ -116,11 +117,13 @@ def __new__(
         writer: Optional["BaseDataCloudWriter"] = None,
         proxy: Optional[BaseProxyClient] = None,
         spark_provider: Optional["BaseSparkSessionProvider"] = None,
+        code_type: str = "script",
     ) -> Client:
+        if "function" in code_type:
+            return cls._new_function_client()
+
         if cls._instance is None:
             cls._instance = super().__new__(cls)
-
-            spark = None
             # Initialize Readers and Writers from config
             # and/or provided reader and writer
             if reader is None or writer is None:
@@ -139,22 +142,6 @@ def __new__(
                     provider = DefaultSparkSessionProvider()
 
                 spark = provider.get_session(config.spark_config)
-            elif (
-                proxy is None
-                and config.proxy_config is not None
-                and config.spark_config is not None
-            ):
-                # Both reader and writer provided; we still need spark for proxy init
-                provider = (
-                    spark_provider
-                    if spark_provider is not None
-                    else (
-                        config.spark_provider_config.to_object()
-                        if config.spark_provider_config is not None
-                        else DefaultSparkSessionProvider()
-                    )
-                )
-                spark = provider.get_session(config.spark_config)
 
             if config.reader_config is None and reader is None:
                 raise ValueError(
@@ -163,28 +150,9 @@ def __new__(
             elif reader is None or (
                 config.reader_config is not None and config.reader_config.force
             ):
-                if config.proxy_config is None:
-                    raise ValueError(
-                        "Proxy config is required when reader is built from config"
-                    )
-                assert (
-                    spark is not None
-                )  # set in "reader is None or writer is None" branch
-                assert config.reader_config is not None  # ensured by branch condition
-                proxy_init = config.proxy_config.to_object(spark)
-
-                reader_init = config.reader_config.to_object(spark)
+                reader_init = config.reader_config.to_object(spark)  # type: ignore
             else:
                 reader_init = reader
-                if proxy is not None:
-                    proxy_init = proxy
-                elif config.proxy_config is None:
-                    raise ValueError("Proxy config is required when reader is provided")
-                else:
-                    assert (
-                        spark is not None
-                    )  # set in "both provided; proxy from config" branch
-                    proxy_init = config.proxy_config.to_object(spark)
             if config.writer_config is None and writer is None:
                 raise ValueError(
                     "Writer config is required when writer is not provided"
@@ -192,15 +160,13 @@ def __new__(
             elif writer is None or (
                 config.writer_config is not None and config.writer_config.force
             ):
-                assert spark is not None  # set when reader or writer from config
-                assert config.writer_config is not None  # ensured by branch condition
-                writer_init = config.writer_config.to_object(spark)
+                writer_init = config.writer_config.to_object(spark)  # type: ignore
             else:
                 writer_init = writer
+
             cls._instance._reader = reader_init
             cls._instance._writer = writer_init
             cls._instance._file = DefaultFindFilePath()
-            cls._instance._proxy = proxy_init
             cls._instance._data_layer_history = {
                 DataCloudObjectType.DLO: set(),
                 DataCloudObjectType.DMO: set(),
@@ -209,6 +175,16 @@ def __new__(
             raise ValueError("Cannot set reader or writer after client is initialized")
         return cls._instance
 
+    @classmethod
+    def _new_function_client(cls) -> Client:
+        cls._instance = super().__new__(cls)
+        cls._instance._proxy = (
+            config.proxy_config.to_object()  # type: ignore
+            if config.proxy_config is not None
+            else None
+        )
+        return cls._instance
+
     def read_dlo(self, name: str) -> PySparkDataFrame:
         """Read a DLO from Data Cloud.
 
@@ -260,6 +236,8 @@ def write_to_dmo(
         return self._writer.write_to_dmo(name, dataframe, write_mode, **kwargs)
 
     def call_llm_gateway(self, LLM_MODEL_ID: str, prompt: str, maxTokens: int) -> str:
+        if self._proxy is None:
+            raise ValueError("No proxy configured; set proxy or proxy_config")
         return self._proxy.call_llm_gateway(LLM_MODEL_ID, prompt, maxTokens)
 
     def find_file_path(self, file_name: str) -> Path:
diff --git a/src/datacustomcode/config.py b/src/datacustomcode/config.py
index b1edfc4..602e182 100644
--- a/src/datacustomcode/config.py
+++ b/src/datacustomcode/config.py
@@ -38,6 +38,7 @@
 from datacustomcode.io.base import BaseDataAccessLayer
 from datacustomcode.io.reader.base import BaseDataCloudReader  # noqa: TCH001
 from datacustomcode.io.writer.base import BaseDataCloudWriter  # noqa: TCH001
+from datacustomcode.proxy.base import BaseProxyAccessLayer
 from datacustomcode.proxy.client.base import BaseProxyClient  # noqa: TCH001
 from datacustomcode.spark.base import BaseSparkSessionProvider
 
@@ -93,6 +94,23 @@ class SparkConfig(ForceableConfig):
 
 _P = TypeVar("_P", bound=BaseSparkSessionProvider)
 
+_PX = TypeVar("_PX", bound=BaseProxyAccessLayer)
+
+
+class ProxyAccessLayerObjectConfig(ForceableConfig, Generic[_PX]):
+    """Config for proxy clients that take no constructor args (e.g. no spark)."""
+
+    model_config = ConfigDict(validate_default=True, extra="forbid")
+    type_base: ClassVar[Type[BaseProxyAccessLayer]] = BaseProxyAccessLayer
+    type_config_name: str = Field(
+        description="CONFIG_NAME of the proxy client (e.g. 'LocalProxyClient').",
+    )
+    options: dict[str, Any] = Field(default_factory=dict)
+
+    def to_object(self) -> _PX:
+        type_ = self.type_base.subclass_from_config_name(self.type_config_name)
+        return cast(_PX, type_(**self.options))
+
 
 class SparkProviderConfig(ForceableConfig, Generic[_P]):
     model_config = ConfigDict(validate_default=True, extra="forbid")
@@ -110,7 +128,7 @@ def to_object(self) -> _P:
 class ClientConfig(BaseModel):
     reader_config: Union[AccessLayerObjectConfig[BaseDataCloudReader], None] = None
     writer_config: Union[AccessLayerObjectConfig[BaseDataCloudWriter], None] = None
-    proxy_config: Union[AccessLayerObjectConfig[BaseProxyClient], None] = None
+    proxy_config: Union[ProxyAccessLayerObjectConfig[BaseProxyClient], None] = None
     spark_config: Union[SparkConfig, None] = None
     spark_provider_config: Union[
         SparkProviderConfig[BaseSparkSessionProvider], None
diff --git a/src/datacustomcode/proxy/base.py b/src/datacustomcode/proxy/base.py
index cba92f6..71cf314 100644
--- a/src/datacustomcode/proxy/base.py
+++ b/src/datacustomcode/proxy/base.py
@@ -19,6 +19,6 @@
 from datacustomcode.mixin import UserExtendableNamedConfigMixin
 
 
-class BaseDataAccessLayer(ABC, UserExtendableNamedConfigMixin):
+class BaseProxyAccessLayer(ABC, UserExtendableNamedConfigMixin):
     def __init__(self):
         pass
diff --git a/src/datacustomcode/proxy/client/local_proxy_client.py b/src/datacustomcode/proxy/client/LocalProxyClientProvider.py
similarity index 94%
rename from src/datacustomcode/proxy/client/local_proxy_client.py
rename to src/datacustomcode/proxy/client/LocalProxyClientProvider.py
index 2c2f962..515db00 100644
--- a/src/datacustomcode/proxy/client/local_proxy_client.py
+++ b/src/datacustomcode/proxy/client/LocalProxyClientProvider.py
@@ -22,5 +22,8 @@ class LocalProxyClientProvider(BaseProxyClient):
 
     CONFIG_NAME = "LocalProxyClientProvider"
 
+    def __init__(self, **kwargs: object) -> None:
+        pass
+
     def call_llm_gateway(self, llmModelId: str, prompt: str, maxTokens: int) -> str:
         return f"Hello, thanks for using {llmModelId}. So many tokens: {maxTokens}"
diff --git a/src/datacustomcode/proxy/client/base.py b/src/datacustomcode/proxy/client/base.py
index 3c4a56b..5c840a0 100644
--- a/src/datacustomcode/proxy/client/base.py
+++ b/src/datacustomcode/proxy/client/base.py
@@ -16,13 +16,12 @@
 
 from abc import abstractmethod
 
-from datacustomcode.io.base import BaseDataAccessLayer
+from datacustomcode.proxy.base import BaseProxyAccessLayer
 
 
-class BaseProxyClient(BaseDataAccessLayer):
-    def __init__(self, spark=None, **kwargs):
-        if spark is not None:
-            super().__init__(spark)
+class BaseProxyClient(BaseProxyAccessLayer):
+    def __init__(self):
+        pass
 
     @abstractmethod
     def call_llm_gateway(self, llmModelId: str, prompt: str, maxTokens: int) -> str: ...