diff --git a/examples/input_variables_file.py b/examples/input_variables_file.py
new file mode 100644
index 0000000..46ee2a0
--- /dev/null
+++ b/examples/input_variables_file.py
@@ -0,0 +1,28 @@
+import asyncio
+from io import BytesIO
+
+from narada import Agent, Narada
+
+
+async def main() -> None:
+    async with Narada() as narada:
+        window = await narada.open_and_initialize_browser_window()
+
+        # Create an in-memory file object and pass it in input_variables.
+        # The SDK uploads it automatically before dispatching the request.
+        file_obj = BytesIO(
+            b"This is a sample document for input_variables file upload."
+        )
+        file_obj.name = "sample_document.txt"
+
+        response = await window.agent(
+            prompt="Summarize {{$doc}}.",
+            agent=Agent.CORE_AGENT,
+            input_variables={"doc": file_obj},
+        )
+
+        print("Response:", response.model_dump_json(indent=2))
+
+
+if __name__ == "__main__":
+    asyncio.run(main())
diff --git a/packages/narada/README.md b/packages/narada/README.md
index ee6085f..b19fda4 100644
--- a/packages/narada/README.md
+++ b/packages/narada/README.md
@@ -73,7 +73,7 @@ You can use the SDK to launch browsers and run automated tasks using natural lan
 
 ## Migration note
 
-For the next release (`0.1.38`):
+For releases `0.1.38` and later:
 
 - `variables` has been renamed to `secret_variables`.
 - Use `input_variables` to pass structured values (objects/arrays) into custom agents.
diff --git a/packages/narada/pyproject.toml b/packages/narada/pyproject.toml
index 594d9c3..cab7376 100644
--- a/packages/narada/pyproject.toml
+++ b/packages/narada/pyproject.toml
@@ -1,6 +1,6 @@
 [project]
 name = "narada"
-version = "0.1.41"
+version = "0.1.42"
 description = "Python client SDK for Narada"
 license = "Apache-2.0"
 readme = "README.md"
diff --git a/packages/narada/src/narada/window.py b/packages/narada/src/narada/window.py
index 60a8634..2b61390 100644
--- a/packages/narada/src/narada/window.py
+++ b/packages/narada/src/narada/window.py
@@ -5,8 +5,9 @@
 from abc import ABC
 from dataclasses import dataclass
 from http import HTTPStatus
+from io import IOBase
 from pathlib import Path
-from typing import IO, Any, TypeVar, overload, override
+from typing import IO, Any, Mapping, TypeGuard, TypeVar, overload, override
 
 import aiohttp
 from narada_core.actions.models import (
@@ -65,6 +66,28 @@
 _ResponseModel = TypeVar("_ResponseModel", bound=BaseModel)
 
 
+class _InputVariableFileReference(BaseModel):
+    key: str
+    name: str
+
+
+type _JsonPrimitive = str | int | float | bool | None
+type _InputVariableValue = (
+    _JsonPrimitive
+    | IOBase
+    | list["_InputVariableValue"]
+    | dict[str, "_InputVariableValue"]
+)
+type _InputVariables = dict[str, _InputVariableValue]
+type _NormalizedInputVariableValue = (
+    _JsonPrimitive
+    | _InputVariableFileReference
+    | list["_NormalizedInputVariableValue"]
+    | dict[str, "_NormalizedInputVariableValue"]
+)
+type _NormalizedInputVariables = dict[str, _NormalizedInputVariableValue]
+
+
 class _PresignedPost(BaseModel):
     url: str
     fields: dict[str, Any]
@@ -105,6 +128,11 @@ async def upload_file(self, *, file: IO) -> File:
         The file is temporarily saved in Narada cloud and expires after 1 day. It can only be
         accessed by the user who uploaded it.
         """
+        # TODO: We will deprecate this public method in favor of automatic upload via
+        # input_variables file objects.
+        return await self._upload_file_impl(file=file)
+
+    async def _upload_file_impl(self, *, file: IO[Any]) -> File:
         # Get the base filename without directories.
         filename = Path(file.name).name
 
@@ -132,6 +160,54 @@ async def upload_file(self, *, file: IO) -> File:
 
         return File(key=object_key)
 
+    async def _normalize_input_variables(
+        self, *, input_variables: Mapping[str, Any]
+    ) -> _NormalizedInputVariables:
+        normalized: _NormalizedInputVariables = {}
+        for key, value in input_variables.items():
+            normalized[key] = await self._normalize_input_variables_value_impl(
+                input_variable_value=value
+            )
+        return normalized
+
+    async def _normalize_input_variables_value_impl(
+        self, *, input_variable_value: Any
+    ) -> _NormalizedInputVariableValue:
+        if isinstance(input_variable_value, list):
+            return [
+                await self._normalize_input_variables_value_impl(
+                    input_variable_value=item
+                )
+                for item in input_variable_value
+            ]
+
+        if self._is_uploadable_file(input_variable_value):
+            return await self._upload_input_variable_file(
+                input_variable_value=input_variable_value
+            )
+
+        if isinstance(input_variable_value, dict):
+            normalized: dict[str, _NormalizedInputVariableValue] = {}
+            for key, value in input_variable_value.items():
+                normalized[key] = await self._normalize_input_variables_value_impl(
+                    input_variable_value=value
+                )
+            return normalized
+
+        return input_variable_value
+
+    @staticmethod
+    def _is_uploadable_file(value: Any) -> TypeGuard[IO[Any]]:
+        # Keep runtime eligibility aligned with current upload_file expectations.
+        return isinstance(value, IOBase) and hasattr(value, "name")
+
+    async def _upload_input_variable_file(
+        self, *, input_variable_value: IO[Any]
+    ) -> _InputVariableFileReference:
+        filename = Path(input_variable_value.name).name
+        uploaded_file = await self._upload_file_impl(file=input_variable_value)
+        return _InputVariableFileReference(key=uploaded_file["key"], name=filename)
+
     @overload
     async def dispatch_request(
         self,
@@ -149,10 +225,10 @@ async def dispatch_request(
         user_resource_credentials: UserResourceCredentials | None = None,
         mcp_servers: list[McpServer] | None = None,
         secret_variables: dict[str, str] | None = None,
-        input_variables: dict[str, Any] | None = None,
+        input_variables: Mapping[str, Any] | None = None,
         callback_url: str | None = None,
         callback_secret: str | None = None,
-        callback_headers: dict[str, Any] | None = None,
+        callback_headers: Mapping[str, Any] | None = None,
         timeout: int = 1000,
     ) -> Response[None]: ...
 
@@ -173,10 +249,10 @@ async def dispatch_request(
         user_resource_credentials: UserResourceCredentials | None = None,
         mcp_servers: list[McpServer] | None = None,
         secret_variables: dict[str, str] | None = None,
-        input_variables: dict[str, Any] | None = None,
+        input_variables: Mapping[str, Any] | None = None,
         callback_url: str | None = None,
         callback_secret: str | None = None,
-        callback_headers: dict[str, Any] | None = None,
+        callback_headers: Mapping[str, Any] | None = None,
         timeout: int = 1000,
     ) -> Response[_StructuredOutput]: ...
 
@@ -196,10 +272,10 @@ async def dispatch_request(
         user_resource_credentials: UserResourceCredentials | None = None,
         mcp_servers: list[McpServer] | None = None,
         secret_variables: dict[str, str] | None = None,
-        input_variables: dict[str, Any] | None = None,
+        input_variables: Mapping[str, Any] | None = None,
         callback_url: str | None = None,
         callback_secret: str | None = None,
-        callback_headers: dict[str, Any] | None = None,
+        callback_headers: Mapping[str, Any] | None = None,
         timeout: int = 1000,
     ) -> Response:
         """Low-level API for invoking an agent in the Narada extension side panel chat.
@@ -242,7 +318,9 @@ async def dispatch_request(
         if secret_variables is not None:
             body["secretVariables"] = secret_variables
         if input_variables is not None:
-            body["inputVariables"] = input_variables
+            body["inputVariables"] = await self._normalize_input_variables(
+                input_variables=input_variables
+            )
         if callback_url is not None:
             body["callbackUrl"] = callback_url
         if callback_secret is not None:
@@ -312,7 +390,7 @@ async def agent(
         time_zone: str = "America/Los_Angeles",
         mcp_servers: list[McpServer] | None = None,
         secret_variables: dict[str, str] | None = None,
-        input_variables: dict[str, Any] | None = None,
+        input_variables: Mapping[str, Any] | None = None,
         timeout: int = 1000,
     ) -> AgentResponse[dict[str, Any]]: ...
 
@@ -329,7 +407,7 @@ async def agent(
         time_zone: str = "America/Los_Angeles",
         mcp_servers: list[McpServer] | None = None,
         secret_variables: dict[str, str] | None = None,
-        input_variables: dict[str, Any] | None = None,
+        input_variables: Mapping[str, Any] | None = None,
         timeout: int = 1000,
     ) -> AgentResponse[_StructuredOutput]: ...
 
@@ -345,7 +423,7 @@ async def agent(
         time_zone: str = "America/Los_Angeles",
         mcp_servers: list[McpServer] | None = None,
         secret_variables: dict[str, str] | None = None,
-        input_variables: dict[str, Any] | None = None,
+        input_variables: Mapping[str, Any] | None = None,
         timeout: int = 1000,
     ) -> AgentResponse:
         """Invokes an agent in the Narada extension side panel chat."""
diff --git a/uv.lock b/uv.lock
index 80c860f..5fd8861 100644
--- a/uv.lock
+++ b/uv.lock
@@ -1,5 +1,5 @@
 version = 1
-revision = 3
+revision = 2
 requires-python = ">=3.12"
 resolution-markers = [
     "python_full_version >= '3.13'",
@@ -312,7 +312,7 @@ wheels = [
 
 [[package]]
 name = "narada"
-version = "0.1.41"
+version = "0.1.42"
 source = { editable = "packages/narada" }
 dependencies = [
     { name = "aiohttp" },