diff --git a/.beads/issues.jsonl b/.beads/issues.jsonl
index f3a1047..8ae7b57 100644
--- a/.beads/issues.jsonl
+++ b/.beads/issues.jsonl
@@ -1,22 +1,22 @@
-{"id":"vgi-python-0hr","title":"Remove redundant InitInputType class attribute","description":"InitInputType class attribute duplicates the generic type parameter: 'class ScalarFunctionGenerator(Function[FunctionInitInput])' already specifies the type, but 'InitInputType = FunctionInitInput' repeats it. Investigate using get_type_hints or __orig_bases__ to infer the type and remove the redundant attribute.","status":"open","priority":3,"issue_type":"task","created_at":"2026-01-04T20:06:53.780529-05:00","created_by":"rusty","updated_at":"2026-01-04T20:07:37.960914-05:00"}
+{"id":"vgi-python-0hr","title":"Remove redundant InitInputType class attribute","description":"InitInputType class attribute duplicates the generic type parameter: 'class ScalarFunctionGenerator(Function[FunctionInitInput])' already specifies the type, but 'InitInputType = FunctionInitInput' repeats it. Investigate using get_type_hints or __orig_bases__ to infer the type and remove the redundant attribute.","status":"in_progress","priority":3,"issue_type":"task","created_at":"2026-01-04T20:06:53.780529-05:00","created_by":"rusty","updated_at":"2026-01-04T21:55:49.902878-05:00"}
 {"id":"vgi-python-1s5","title":"Move distributed state management to optional mixin","description":"The Function base class in function.py includes ~200 lines for distributed state management (store_state, collect_states, enqueue_work, dequeue_work, work queue storage). Not all functions need this. Extract to DistributedStateMixin that functions can opt into, keeping Function base class simpler for basic use cases.","status":"closed","priority":2,"issue_type":"task","created_at":"2026-01-04T20:06:53.606614-05:00","created_by":"rusty","updated_at":"2026-01-04T21:22:09.772825-05:00","closed_at":"2026-01-04T21:22:09.772825-05:00","close_reason":"Analysis complete: extraction not recommended. The distributed state methods are tightly coupled with execution_identifier and storage, which are used by core initialization methods. Extraction would require moving initialize_global_state/load_global_state to the mixin, breaking the protocol and requiring multiple inheritance. Current API is already opt-in (just don't call the methods) and well-documented."}
 {"id":"vgi-python-36f","title":"Split metadata.py Arrow serialization into separate module","description":"metadata.py is 932 lines with two distinct concerns: 1) metadata resolution (enums, dataclasses, parameter extraction, resolve_metadata) and 2) Arrow serialization (schema definitions, to_arrow/from_arrow functions). Split Arrow serialization into metadata_serialization.py or metadata_arrow.py for better separation of concerns.","status":"open","priority":3,"issue_type":"task","created_at":"2026-01-04T20:06:53.481364-05:00","created_by":"rusty","updated_at":"2026-01-04T20:07:37.718814-05:00"}
 {"id":"vgi-python-3fq","title":"Abstract common worker batch processing logic","description":"Worker batch processing methods _process_scalar_batches (377-466), _process_batches (468-550), and _generate_batches (552-593) share significant structure: IPC writer/reader setup, batch counting/logging, main processing loop. Extract common logic to reduce duplication - consider a BatchProcessor helper class or template method pattern.","status":"closed","priority":2,"issue_type":"task","created_at":"2026-01-04T20:06:53.350497-05:00","created_by":"rusty","updated_at":"2026-01-04T21:20:24.509785-05:00","closed_at":"2026-01-04T21:20:24.509785-05:00","close_reason":"Analysis complete: abstraction not warranted. The three methods have sufficiently different logic (input handling, log message loops, protocol types) that abstracting them would add complexity without meaningful benefit. Current code is already readable at ~70-90 lines each."}
-{"id":"vgi-python-5er","title":"Extract _should_terminate into shared base class","description":"Identical _should_terminate method is copy-pasted in all three function modules. Implementation is always: check if log_message exists and level is EXCEPTION. Move to shared base class (Function or new ProcessingMixin) to eliminate duplication.","status":"open","priority":3,"issue_type":"task","created_at":"2026-01-04T20:06:41.190482-05:00","created_by":"rusty","updated_at":"2026-01-04T20:07:16.071737-05:00","dependencies":[{"issue_id":"vgi-python-5er","depends_on_id":"vgi-python-6o0","type":"blocks","created_at":"2026-01-04T20:07:49.283865-05:00","created_by":"rusty"}]}
+{"id":"vgi-python-5er","title":"Extract _should_terminate into shared base class","description":"Identical _should_terminate method is copy-pasted in all three function modules. Implementation is always: check if log_message exists and level is EXCEPTION. Move to shared base class (Function or new ProcessingMixin) to eliminate duplication.","status":"closed","priority":3,"issue_type":"task","created_at":"2026-01-04T20:06:41.190482-05:00","created_by":"rusty","updated_at":"2026-01-04T21:49:59.765614-05:00","closed_at":"2026-01-04T21:49:59.765614-05:00","close_reason":"Completed as part of PR #8 - _should_terminate moved to Function base class","dependencies":[{"issue_id":"vgi-python-5er","depends_on_id":"vgi-python-6o0","type":"blocks","created_at":"2026-01-04T20:07:49.283865-05:00","created_by":"rusty"}]}
 {"id":"vgi-python-67w","title":"Create example function using DuckDB settings","description":"Create an example function that demonstrates using DuckDB settings to determine its output.\n\nRequirements:\n- Function declares required_settings in Meta\n- Output schema depends on a setting value (e.g., include extra column based on setting)\n- Clear documentation showing the pattern\n\nExample ideas:\n1. TimezoneAwareFunction: Output includes timezone info based on 'timezone' setting\n2. VerboseOutput: Adds debug columns when 'debug_mode' setting is true\n3. NumericPrecision: Uses 'numeric_precision' to determine output type precision\n\nAdd to vgi/examples/ and register in ExampleWorker.","status":"closed","priority":2,"issue_type":"task","created_at":"2026-01-04T13:05:48.503681-05:00","created_by":"rusty","updated_at":"2026-01-04T13:22:23.779895-05:00","closed_at":"2026-01-04T13:22:23.779895-05:00","close_reason":"Added SettingsAwareFunction example","dependencies":[{"issue_id":"vgi-python-67w","depends_on_id":"vgi-python-c2b","type":"blocks","created_at":"2026-01-04T13:06:13.865474-05:00","created_by":"rusty"},{"issue_id":"vgi-python-67w","depends_on_id":"vgi-python-ivf","type":"blocks","created_at":"2026-01-04T13:06:13.890269-05:00","created_by":"rusty"},{"issue_id":"vgi-python-67w","depends_on_id":"vgi-python-bqb","type":"blocks","created_at":"2026-01-04T13:06:13.912531-05:00","created_by":"rusty"},{"issue_id":"vgi-python-67w","depends_on_id":"vgi-python-a99","type":"blocks","created_at":"2026-01-04T13:06:13.936552-05:00","created_by":"rusty"},{"issue_id":"vgi-python-67w","depends_on_id":"vgi-python-j4t","type":"blocks","created_at":"2026-01-04T13:06:13.958494-05:00","created_by":"rusty"}]}
 {"id":"vgi-python-6o0","title":"Consolidate _OutputComplete classes into shared module","description":"Three nearly identical _OutputComplete classes exist in scalar_function.py:168-197 (_ScalarOutputComplete), table_function.py:136-175 (_OutputComplete), and table_in_out_function.py:356-400 (_OutputComplete). All are frozen dataclasses with batch field, log_message field, and from_process_result() classmethod. Extract to shared module (e.g., vgi/protocol_types.py) with a single parameterized class.","status":"closed","priority":2,"issue_type":"task","created_at":"2026-01-04T20:06:40.893139-05:00","created_by":"rusty","updated_at":"2026-01-04T21:18:34.529683-05:00","closed_at":"2026-01-04T21:18:34.529683-05:00","close_reason":"PR #5 created: https://github.com/Query-farm/vgi-python/pull/5"}
-{"id":"vgi-python-79e","title":"Unify ProtocolInput classes with shared base","description":"ProtocolInput classes in scalar_function.py:151-166 and table_in_out_function.py:109-142 have similar structure with batch and metadata fields. The table_in_out version adds is_finalize logic. Create shared base ProtocolInput in protocol_types.py with table_in_out extending it.","status":"open","priority":3,"issue_type":"task","created_at":"2026-01-04T20:06:41.31917-05:00","created_by":"rusty","updated_at":"2026-01-04T20:07:16.240397-05:00"}
+{"id":"vgi-python-79e","title":"Unify ProtocolInput classes with shared base","description":"ProtocolInput classes in scalar_function.py:151-166 and table_in_out_function.py:109-142 have similar structure with batch and metadata fields. The table_in_out version adds is_finalize logic. Create shared base ProtocolInput in protocol_types.py with table_in_out extending it.","status":"closed","priority":3,"issue_type":"task","created_at":"2026-01-04T20:06:41.31917-05:00","created_by":"rusty","updated_at":"2026-01-04T21:53:26.965345-05:00","closed_at":"2026-01-04T21:53:26.965345-05:00","close_reason":"PR #9 created - unified ProtocolInput with shared base in protocol_types.py"}
 {"id":"vgi-python-a99","title":"Add settings accessor to function base classes","description":"Add a property to access DuckDB settings values in function implementations.\n\nChanges needed:\n- Add 'settings: dict[str, str]' property to Function base class\n- Property should return self.invocation.duckdb_settings or empty dict\n- Add convenience method like 'get_setting(name, default=None)'\n- Update ScalarFunction, TableFunctionGenerator, TableInOutFunction\n\nExample usage in function:\ndef compute(self, batch):\n    tz = self.get_setting('timezone', 'UTC')\n    # or\n    tz = self.settings.get('timezone', 'UTC')","status":"closed","priority":2,"issue_type":"task","created_at":"2026-01-04T13:05:48.221602-05:00","created_by":"rusty","updated_at":"2026-01-04T13:20:41.171991-05:00","closed_at":"2026-01-04T13:20:41.171991-05:00","close_reason":"Implementation complete, all tests pass","dependencies":[{"issue_id":"vgi-python-a99","depends_on_id":"vgi-python-aad","type":"blocks","created_at":"2026-01-04T13:06:13.738212-05:00","created_by":"rusty"}]}
 {"id":"vgi-python-aad","title":"Design: DuckDB settings/pragmas access for VGI functions","description":"Design how VGI functions can declare required DuckDB settings/pragmas in their Meta class, and how these settings values should be passed during the bind phase.\n\nKey design decisions:\n1. How to declare required settings in function Meta (e.g., required_settings = ['timezone', 'threads'])\n2. How to add settings to Invocation dataclass\n3. How settings values should be accessed in function code\n4. Serialization format for settings in Arrow IPC\n\nRecommendation: Add 'duckdb_settings: dict[str, str] | None' to Invocation and 'required_settings: list[str]' to Meta class.","status":"closed","priority":1,"issue_type":"task","created_at":"2026-01-04T13:05:47.619105-05:00","created_by":"rusty","updated_at":"2026-01-04T13:11:13.197139-05:00","closed_at":"2026-01-04T13:11:13.197139-05:00","close_reason":"Design document created at docs/design-duckdb-settings.md"}
-{"id":"vgi-python-bi8","title":"Extract common _process_with_exception_handling into mixin","description":"The _process_with_exception_handling and _process_and_validate methods are duplicated across scalar_function.py:296-346, table_function.py:386-438, and table_in_out_function.py:586-642. All follow same pattern: try _process_and_validate, catch exceptions, return OutputComplete with error message. Extract to ProcessingMixin that all function types inherit from.","status":"in_progress","priority":2,"issue_type":"task","created_at":"2026-01-04T20:06:41.02111-05:00","created_by":"rusty","updated_at":"2026-01-04T21:44:11.818421-05:00","dependencies":[{"issue_id":"vgi-python-bi8","depends_on_id":"vgi-python-6o0","type":"blocks","created_at":"2026-01-04T20:07:49.181408-05:00","created_by":"rusty"}]}
+{"id":"vgi-python-bi8","title":"Extract common _process_with_exception_handling into mixin","description":"The _process_with_exception_handling and _process_and_validate methods are duplicated across scalar_function.py:296-346, table_function.py:386-438, and table_in_out_function.py:586-642. All follow same pattern: try _process_and_validate, catch exceptions, return OutputComplete with error message. Extract to ProcessingMixin that all function types inherit from.","status":"closed","priority":2,"issue_type":"task","created_at":"2026-01-04T20:06:41.02111-05:00","created_by":"rusty","updated_at":"2026-01-04T21:49:46.320532-05:00","closed_at":"2026-01-04T21:49:46.320532-05:00","close_reason":"PR #8 created - extracted _should_terminate and added _create_error_output to Function base class","dependencies":[{"issue_id":"vgi-python-bi8","depends_on_id":"vgi-python-6o0","type":"blocks","created_at":"2026-01-04T20:07:49.181408-05:00","created_by":"rusty"}]}
 {"id":"vgi-python-bku","title":"Change cardinality() method to property for consistency with output_schema","description":"Inconsistent access patterns: output_schema is a property but cardinality() is a method. Both return immutable data. Change cardinality() to a property for API consistency. Located in table_function.py:304-314.","status":"closed","priority":3,"issue_type":"task","created_at":"2026-01-04T20:06:53.211782-05:00","created_by":"rusty","updated_at":"2026-01-04T21:33:10.617152-05:00","closed_at":"2026-01-04T21:33:10.617152-05:00","close_reason":"PR #6 created: https://github.com/Query-farm/vgi-python/pull/6"}
 {"id":"vgi-python-bqb","title":"Update worker to handle DuckDB settings during bind","description":"Update vgi/worker.py to process DuckDB settings from Invocation during the bind phase.\n\nChanges needed:\n- Read settings from invocation.duckdb_settings\n- Validate that all required_settings (from Meta) are present in invocation\n- Pass settings to function instance for access\n- Log settings usage for debugging\n\nThe worker should validate settings early in bind to fail fast if required settings are missing.","status":"closed","priority":2,"issue_type":"task","created_at":"2026-01-04T13:05:48.04037-05:00","created_by":"rusty","updated_at":"2026-01-04T13:20:41.17079-05:00","closed_at":"2026-01-04T13:20:41.17079-05:00","close_reason":"Implementation complete, all tests pass","dependencies":[{"issue_id":"vgi-python-bqb","depends_on_id":"vgi-python-aad","type":"blocks","created_at":"2026-01-04T13:06:13.714281-05:00","created_by":"rusty"}]}
 {"id":"vgi-python-c2b","title":"Add duckdb_settings field to Invocation class","description":"Update vgi/invocation.py to add a duckdb_settings field to the Invocation dataclass.\n\nChanges needed:\n- Add 'duckdb_settings: dict[str, str] | None = None' field to Invocation\n- Update serialize() to include settings in Arrow IPC batch\n- Update deserialize() to read settings from Arrow IPC batch\n- Handle None case (no settings requested)\n\nSerialization: Use a struct field with string key-value pairs or a map type.","status":"closed","priority":2,"issue_type":"task","created_at":"2026-01-04T13:05:47.765077-05:00","created_by":"rusty","updated_at":"2026-01-04T13:20:41.167817-05:00","closed_at":"2026-01-04T13:20:41.167817-05:00","close_reason":"Implementation complete, all tests pass","dependencies":[{"issue_id":"vgi-python-c2b","depends_on_id":"vgi-python-aad","type":"blocks","created_at":"2026-01-04T13:06:13.664038-05:00","created_by":"rusty"}]}
 {"id":"vgi-python-e37","title":"move Invocation from function.py out to own file","description":"The Invocation clas is kind of seperate from functions, so it should be in its own file.  Move it and all of its other associated classes like InvocationType to its own file","status":"closed","priority":2,"issue_type":"task","created_at":"2026-01-04T09:18:46.605941-05:00","created_by":"rusty","updated_at":"2026-01-04T09:24:37.922675-05:00","closed_at":"2026-01-04T09:24:37.922675-05:00","close_reason":"Closed"}
-{"id":"vgi-python-e9q","title":"Unify ProtocolOutput classes with shared base","description":"ProtocolOutput classes in table_function.py:177-224 and table_in_out_function.py:144-207 share similar metadata() method and from_process_result() classmethod. The table_in_out version adds status field. Create shared base with table_in_out extending it for status support.","status":"open","priority":3,"issue_type":"task","created_at":"2026-01-04T20:06:41.45014-05:00","created_by":"rusty","updated_at":"2026-01-04T20:07:16.371419-05:00"}
+{"id":"vgi-python-e9q","title":"Unify ProtocolOutput classes with shared base","description":"ProtocolOutput classes in table_function.py:177-224 and table_in_out_function.py:144-207 share similar metadata() method and from_process_result() classmethod. The table_in_out version adds status field. Create shared base with table_in_out extending it for status support.","status":"closed","priority":3,"issue_type":"task","created_at":"2026-01-04T20:06:41.45014-05:00","created_by":"rusty","updated_at":"2026-01-04T21:54:55.871986-05:00","closed_at":"2026-01-04T21:54:55.871986-05:00","close_reason":"Not warranted - dataclass inheritance with slots=True doesn't allow adding required field (status) between inherited fields. The classes have different semantics (table_in_out requires status for generator state tracking) making inheritance impractical."}
 {"id":"vgi-python-ivf","title":"Add required_settings to function Meta class","description":"Update function metadata to support declaring required DuckDB settings.\n\nChanges needed:\n- Add 'required_settings: list[str]' to FunctionMeta in vgi/metadata.py\n- Update Meta class resolution in vgi/function.py\n- Add validation that required_settings is a list of strings\n- Make it available via get_metadata() for introspection\n\nExample usage:\nclass MyFunction(TableInOutFunction):\n    class Meta:\n        required_settings = ['timezone', 'threads']","status":"closed","priority":2,"issue_type":"task","created_at":"2026-01-04T13:05:47.903747-05:00","created_by":"rusty","updated_at":"2026-01-04T13:20:41.169516-05:00","closed_at":"2026-01-04T13:20:41.169516-05:00","close_reason":"Implementation complete, all tests pass","dependencies":[{"issue_id":"vgi-python-ivf","depends_on_id":"vgi-python-aad","type":"blocks","created_at":"2026-01-04T13:06:13.690253-05:00","created_by":"rusty"}]}
 {"id":"vgi-python-j4t","title":"Update client to pass DuckDB settings in Invocation","description":"Update vgi/client/client.py to support passing DuckDB settings.\n\nChanges needed:\n- Add 'duckdb_settings: dict[str, str] | None = None' parameter to relevant methods\n- Include settings in Invocation creation\n- Add helper to query function's required_settings from metadata\n\nThe client needs to know what settings to pass. Options:\n1. Client queries worker for function metadata first\n2. Settings passed explicitly by caller\n3. Client introspects function class if available locally","status":"closed","priority":2,"issue_type":"task","created_at":"2026-01-04T13:05:48.358656-05:00","created_by":"rusty","updated_at":"2026-01-04T13:20:41.173178-05:00","closed_at":"2026-01-04T13:20:41.173178-05:00","close_reason":"Implementation complete, all tests pass","dependencies":[{"issue_id":"vgi-python-j4t","depends_on_id":"vgi-python-aad","type":"blocks","created_at":"2026-01-04T13:06:13.761572-05:00","created_by":"rusty"}]}
-{"id":"vgi-python-kz4","title":"Rename TableInOutGeneratorFunction to TableInOutGenerator for consistency","description":"Naming inconsistency: TableFunctionGenerator uses *Generator suffix, but TableInOutGeneratorFunction uses *GeneratorFunction suffix. Rename TableInOutGeneratorFunction to TableInOutGenerator for consistency. Also consider renaming ScalarFunctionGenerator if needed.","status":"in_progress","priority":3,"issue_type":"task","created_at":"2026-01-04T20:06:41.581028-05:00","created_by":"rusty","updated_at":"2026-01-04T21:39:29.83686-05:00"}
+{"id":"vgi-python-kz4","title":"Rename TableInOutGeneratorFunction to TableInOutGenerator for consistency","description":"Naming inconsistency: TableFunctionGenerator uses *Generator suffix, but TableInOutGeneratorFunction uses *GeneratorFunction suffix. Rename TableInOutGeneratorFunction to TableInOutGenerator for consistency. Also consider renaming ScalarFunctionGenerator if needed.","status":"closed","priority":3,"issue_type":"task","created_at":"2026-01-04T20:06:41.581028-05:00","created_by":"rusty","updated_at":"2026-01-04T21:43:58.141038-05:00","closed_at":"2026-01-04T21:43:58.141038-05:00","close_reason":"PR #7 created: https://github.com/Query-farm/vgi-python/pull/7"}
 {"id":"vgi-python-odi","title":"Change max_processes from method to property in Function hierarchy","description":"Refactor max_processes from a method to a property across the Function class hierarchy (Function, ScalarFunction, TableFunctionGenerator, TableInOutFunction, etc.). This makes the API more consistent since max_processes is effectively a constant per function class and properties are more idiomatic for such values.","status":"closed","priority":2,"issue_type":"task","created_at":"2026-01-04T11:25:29.750648-05:00","created_by":"rusty","updated_at":"2026-01-04T11:50:57.566545-05:00","closed_at":"2026-01-04T11:50:57.566545-05:00","close_reason":"Closed"}
 {"id":"vgi-python-p91","title":"Move exception classes from function.py to own file","description":"Move InitIdentifierError and SchemaValidationError from vgi/function.py to a new vgi/exceptions.py file. Update imports in function.py and any other files that reference these exceptions.","status":"closed","priority":2,"issue_type":"task","created_at":"2026-01-04T09:12:28.058227-05:00","created_by":"rusty","updated_at":"2026-01-04T09:17:52.477661-05:00","closed_at":"2026-01-04T09:17:52.477661-05:00","close_reason":"Closed"}
 {"id":"vgi-python-r3t","title":"Consolidate test client infrastructure in testing.py","description":"testing.py has three test client classes (FunctionTestClient, TableFunctionTestClient, ScalarFunctionTestClient) with shared infrastructure patterns. Extend _BaseTestClient pattern to reduce code duplication. Consider using a single unified client with method dispatch based on function type.","status":"open","priority":3,"issue_type":"task","created_at":"2026-01-04T20:06:53.913912-05:00","created_by":"rusty","updated_at":"2026-01-04T20:07:38.132591-05:00"}
diff --git a/vgi/function.py b/vgi/function.py
index 19d7621..d1c427f 100644
--- a/vgi/function.py
+++ b/vgi/function.py
@@ -35,7 +35,10 @@
     Protocol,
     Self,
     TypeVar,
+    cast,
     final,
+    get_args,
+    get_origin,
 )
 
 import pyarrow as pa
@@ -275,9 +278,37 @@ class Meta:
     execution_identifier: bytes | None = None
 
     # This is the init data that may be been read.
-    InitInputType: type[T]
+    # Type inferred from generic parameter via _get_init_input_type()
     init_input: T | None = None
 
+    # Cache for _get_init_input_type per class
+    _init_input_type_cache: ClassVar[dict[type, type["FunctionInitInput"]]] = {}
+
+    @classmethod
+    def _get_init_input_type(cls) -> type["FunctionInitInput"]:
+        """Get the InitInput type from the generic parameter.
+
+        Walks the MRO to find Function[T] and extracts T.
+        Result is cached per class.
+        """
+        if cls in cls._init_input_type_cache:
+            return cls._init_input_type_cache[cls]
+
+        for base in cls.__mro__:
+            if hasattr(base, "__orig_bases__"):
+                for orig_base in base.__orig_bases__:
+                    origin = get_origin(orig_base)
+                    if origin is not None and origin.__name__ == "Function":
+                        args = get_args(orig_base)
+                        if args:
+                            init_type = cast(type["FunctionInitInput"], args[0])
+                            cls._init_input_type_cache[cls] = init_type
+                            return init_type
+
+        # Fallback to base type if not found
+        cls._init_input_type_cache[cls] = FunctionInitInput
+        return FunctionInitInput
+
     def __init__(
         self,
         *,
@@ -669,7 +700,8 @@ def _validate_input_schema(self, batch: pa.RecordBatch) -> None:
 
     def initialize_global_state(self, init_input: pa.RecordBatch) -> InitResult:
         """Perform a new init call and store it in the storage."""
-        self.init_input = self.InitInputType.deserialize(init_input)
+        init_type = self._get_init_input_type()
+        self.init_input = cast(T, init_type.deserialize(init_input))
         assert self.init_input is not None
         self.execution_identifier = self.storage.global_put(self.init_input.serialize())
         return InitResult(self.execution_identifier)
@@ -682,8 +714,9 @@ def load_global_state(self, init_input: InitResult) -> None:
                 "Ensure initialize_global_state() returns a valid InitResult."
             )
         self.execution_identifier = init_input.global_execution_identifier
-        self.init_input = self.InitInputType.deserialize_bytes(
-            self.storage.global_get(self.execution_identifier)
+        init_type = self._get_init_input_type()
+        self.init_input = cast(
+            T, init_type.deserialize_bytes(self.storage.global_get(self.execution_identifier))
         )
 
     def setup(self) -> None:
diff --git a/vgi/scalar_function.py b/vgi/scalar_function.py
index 2ee9f2c..63f5dc0 100644
--- a/vgi/scalar_function.py
+++ b/vgi/scalar_function.py
@@ -223,7 +223,7 @@ def process(self, batch: pa.RecordBatch) -> ScalarOutputGenerator:
 
     """
 
-    InitInputType = vgi.function.FunctionInitInput
+    # InitInputType inferred from generic parameter Function[FunctionInitInput]
 
     def __init__(
         self,
diff --git a/vgi/table_function.py b/vgi/table_function.py
index f1ecae5..776f84c 100644
--- a/vgi/table_function.py
+++ b/vgi/table_function.py
@@ -242,7 +242,7 @@ class TableFunctionBase(vgi.function.Function[TableFunctionInitInput]):
 
     """
 
-    InitInputType = TableFunctionInitInput
+    # InitInputType inferred from generic parameter Function[TableFunctionInitInput]
     init_input: TableFunctionInitInput | None = None
 
     def __init__(