diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 5c25245b..f3ab5ac4 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -35,24 +35,40 @@ jobs:
       - name: Run lints
         run: ./scripts/lint
 
-  upload:
-    if: github.repository == 'stainless-sdks/riza-api-python' && (github.event_name == 'push' || github.event.pull_request.head.repo.fork)
+  build:
+    if: github.event_name == 'push' || github.event.pull_request.head.repo.fork
     timeout-minutes: 10
-    name: upload
+    name: build
     permissions:
       contents: read
       id-token: write
-    runs-on: depot-ubuntu-24.04
+    runs-on: ${{ github.repository == 'stainless-sdks/riza-api-python' && 'depot-ubuntu-24.04' || 'ubuntu-latest' }}
     steps:
       - uses: actions/checkout@v4
 
+      - name: Install Rye
+        run: |
+          curl -sSf https://rye.astral.sh/get | bash
+          echo "$HOME/.rye/shims" >> $GITHUB_PATH
+        env:
+          RYE_VERSION: '0.44.0'
+          RYE_INSTALL_OPTION: '--yes'
+
+      - name: Install dependencies
+        run: rye sync --all-features
+
+      - name: Run build
+        run: rye build
+
       - name: Get GitHub OIDC Token
+        if: github.repository == 'stainless-sdks/riza-api-python'
         id: github-oidc
         uses: actions/github-script@v6
         with:
           script: core.setOutput('github_token', await core.getIDToken());
 
       - name: Upload tarball
+        if: github.repository == 'stainless-sdks/riza-api-python'
         env:
           URL: https://pkg.stainless.com/s
           AUTH: ${{ steps.github-oidc.outputs.github_token }}
diff --git a/.gitignore b/.gitignore
index 87797408..95ceb189 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,5 +1,4 @@
 .prism.log
-.vscode
 _dev
 
 __pycache__
diff --git a/.release-please-manifest.json b/.release-please-manifest.json
index a7130553..d52d2b97 100644
--- a/.release-please-manifest.json
+++ b/.release-please-manifest.json
@@ -1,3 +1,3 @@
 {
-  ".": "0.12.0"
+  ".": "0.13.0"
 }
\ No newline at end of file
diff --git a/.vscode/settings.json b/.vscode/settings.json
new file mode 100644
index 00000000..5b010307
--- /dev/null
+++ b/.vscode/settings.json
@@ -0,0 +1,3 @@
+{
+    "python.analysis.importFormat": "relative",
+}
diff --git a/CHANGELOG.md b/CHANGELOG.md
index ec895513..5a125fb3 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,39 @@
 # Changelog
 
+## 0.13.0 (2025-08-27)
+
+Full Changelog: [v0.12.0...v0.13.0](https://github.com/riza-io/riza-api-python/compare/v0.12.0...v0.13.0)
+
+### Features
+
+* **api:** api update ([382486c](https://github.com/riza-io/riza-api-python/commit/382486c74c65eea1194720b45ece9591d4d41af3))
+* clean up environment call outs ([8769bb2](https://github.com/riza-io/riza-api-python/commit/8769bb2c3c2c1f27f9b3376784e6aea508605f06))
+* **client:** support file upload requests ([1087c71](https://github.com/riza-io/riza-api-python/commit/1087c71fb0bf395b432d4fc431ee6603692e4136))
+
+
+### Bug Fixes
+
+* avoid newer type syntax ([9a18d40](https://github.com/riza-io/riza-api-python/commit/9a18d4006f1bf12a65155058c38a350d50f54c4d))
+* **client:** don't send Content-Type header on GET requests ([bd53e69](https://github.com/riza-io/riza-api-python/commit/bd53e69b195f87bde9d7fb9e5d0b53e1c6fe8115))
+* **parsing:** correctly handle nested discriminated unions ([8d47022](https://github.com/riza-io/riza-api-python/commit/8d47022a13eee3e79257a1b5f05fb5f1c011356d))
+* **parsing:** ignore empty metadata ([13c6372](https://github.com/riza-io/riza-api-python/commit/13c637238f21a0e1d107ef93ff68aa64544d80b4))
+* **parsing:** parse extra field types ([7d02baf](https://github.com/riza-io/riza-api-python/commit/7d02baf3b6f9b21004709680918f988e39b1c67e))
+
+
+### Chores
+
+* **ci:** change upload type ([d9528d6](https://github.com/riza-io/riza-api-python/commit/d9528d63ccb73418a25fd4faf7780503e59effb9))
+* **internal:** bump pinned h11 dep ([90fc2e5](https://github.com/riza-io/riza-api-python/commit/90fc2e5f508cfafe32e4c01aeb47ff48d2cf97a5))
+* **internal:** change ci workflow machines ([0d557ec](https://github.com/riza-io/riza-api-python/commit/0d557ec5e70c449738f311582b5816fc356baa47))
+* **internal:** fix ruff target version ([aa45f88](https://github.com/riza-io/riza-api-python/commit/aa45f883a7987c82ac55f32c0cd574df06e51a30))
+* **internal:** update comment in script ([0035775](https://github.com/riza-io/riza-api-python/commit/003577545ff551df4172905dba95d7375ef91416))
+* **internal:** update pyright exclude list ([e031abb](https://github.com/riza-io/riza-api-python/commit/e031abb28b1171dac9169607d11b7153a326fd95))
+* **package:** mark python 3.13 as supported ([05a0bcf](https://github.com/riza-io/riza-api-python/commit/05a0bcf5f142708df85b1cb43629440f17425286))
+* **project:** add settings file for vscode ([0166e57](https://github.com/riza-io/riza-api-python/commit/0166e5774e72bcea4a532baafecb1ad513883616))
+* **readme:** fix version rendering on pypi ([d5a15da](https://github.com/riza-io/riza-api-python/commit/d5a15daab691ce39320b92570cb03e05500f9553))
+* update @stainless-api/prism-cli to v5.15.0 ([bba0d03](https://github.com/riza-io/riza-api-python/commit/bba0d03cb1b6bdd875c1683073f1bd63211b7067))
+* update github action ([343e3ec](https://github.com/riza-io/riza-api-python/commit/343e3ec7a6bf8cb4bc9dccdae89a5e41d0fe178c))
+
 ## 0.12.0 (2025-06-29)
 
 Full Changelog: [v0.11.0...v0.12.0](https://github.com/riza-io/riza-api-python/compare/v0.11.0...v0.12.0)
diff --git a/README.md b/README.md
index da31a2a6..6423d936 100644
--- a/README.md
+++ b/README.md
@@ -1,6 +1,7 @@
 # Riza Python API library
 
-[![PyPI version](<https://img.shields.io/pypi/v/rizaio.svg?label=pypi%20(stable)>)](https://pypi.org/project/rizaio/)
+<!-- prettier-ignore -->
+[![PyPI version](https://img.shields.io/pypi/v/rizaio.svg?label=pypi%20(stable))](https://pypi.org/project/rizaio/)
 
 The Riza Python library provides convenient access to the Riza REST API from any Python 3.8+
 application. The library includes type definitions for all request params and response fields,
@@ -84,7 +85,6 @@ pip install rizaio[aiohttp]
 Then you can enable it by instantiating the client with `http_client=DefaultAioHttpClient()`:
 
 ```python
-import os
 import asyncio
 from rizaio import DefaultAioHttpClient
 from rizaio import AsyncRiza
@@ -92,7 +92,7 @@ from rizaio import AsyncRiza
 
 async def main() -> None:
     async with AsyncRiza(
-        api_key=os.environ.get("RIZA_API_KEY"),  # This is the default and can be omitted
+        api_key="My API Key",
         http_client=DefaultAioHttpClient(),
     ) as client:
         response = await client.command.exec(
diff --git a/pyproject.toml b/pyproject.toml
index 529e45ae..c0ef3df1 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -1,6 +1,6 @@
 [project]
 name = "rizaio"
-version = "0.12.0"
+version = "0.13.0"
 description = "The official Python library for the riza API"
 dynamic = ["readme"]
 license = "Apache-2.0"
@@ -24,6 +24,7 @@ classifiers = [
   "Programming Language :: Python :: 3.10",
   "Programming Language :: Python :: 3.11",
   "Programming Language :: Python :: 3.12",
+  "Programming Language :: Python :: 3.13",
   "Operating System :: OS Independent",
   "Operating System :: POSIX",
   "Operating System :: MacOS",
@@ -38,7 +39,7 @@ Homepage = "https://github.com/riza-io/riza-api-python"
 Repository = "https://github.com/riza-io/riza-api-python"
 
 [project.optional-dependencies]
-aiohttp = ["aiohttp", "httpx_aiohttp>=0.1.6"]
+aiohttp = ["aiohttp", "httpx_aiohttp>=0.1.8"]
 
 [tool.rye]
 managed = true
@@ -147,6 +148,7 @@ exclude = [
     "_dev",
     ".venv",
     ".nox",
+    ".git",
 ]
 
 reportImplicitOverride = true
@@ -158,7 +160,7 @@ reportPrivateUsage = false
 [tool.ruff]
 line-length = 120
 output-format = "grouped"
-target-version = "py37"
+target-version = "py38"
 
 [tool.ruff.format]
 docstring-code-format = true
diff --git a/requirements-dev.lock b/requirements-dev.lock
index 9b2900ca..87254a38 100644
--- a/requirements-dev.lock
+++ b/requirements-dev.lock
@@ -48,15 +48,15 @@ filelock==3.12.4
 frozenlist==1.6.2
     # via aiohttp
     # via aiosignal
-h11==0.14.0
+h11==0.16.0
     # via httpcore
-httpcore==1.0.2
+httpcore==1.0.9
     # via httpx
 httpx==0.28.1
     # via httpx-aiohttp
     # via respx
     # via rizaio
-httpx-aiohttp==0.1.6
+httpx-aiohttp==0.1.8
     # via rizaio
 idna==3.4
     # via anyio
diff --git a/requirements.lock b/requirements.lock
index 77a9e6ad..3abce5f7 100644
--- a/requirements.lock
+++ b/requirements.lock
@@ -36,14 +36,14 @@ exceptiongroup==1.2.2
 frozenlist==1.6.2
     # via aiohttp
     # via aiosignal
-h11==0.14.0
+h11==0.16.0
     # via httpcore
-httpcore==1.0.2
+httpcore==1.0.9
     # via httpx
 httpx==0.28.1
     # via httpx-aiohttp
     # via rizaio
-httpx-aiohttp==0.1.6
+httpx-aiohttp==0.1.8
     # via rizaio
 idna==3.4
     # via anyio
diff --git a/scripts/mock b/scripts/mock
index d2814ae6..0b28f6ea 100755
--- a/scripts/mock
+++ b/scripts/mock
@@ -21,7 +21,7 @@ echo "==> Starting mock server with URL ${URL}"
 
 # Run prism mock on the given spec
 if [ "$1" == "--daemon" ]; then
-  npm exec --package=@stainless-api/prism-cli@5.8.5 -- prism mock "$URL" &> .prism.log &
+  npm exec --package=@stainless-api/prism-cli@5.15.0 -- prism mock "$URL" &> .prism.log &
 
   # Wait for server to come online
   echo -n "Waiting for server"
@@ -37,5 +37,5 @@ if [ "$1" == "--daemon" ]; then
 
   echo
 else
-  npm exec --package=@stainless-api/prism-cli@5.8.5 -- prism mock "$URL"
+  npm exec --package=@stainless-api/prism-cli@5.15.0 -- prism mock "$URL"
 fi
diff --git a/scripts/test b/scripts/test
index 2b878456..dbeda2d2 100755
--- a/scripts/test
+++ b/scripts/test
@@ -43,7 +43,7 @@ elif ! prism_is_running ; then
   echo -e "To run the server, pass in the path or url of your OpenAPI"
   echo -e "spec to the prism command:"
   echo
-  echo -e "  \$ ${YELLOW}npm exec --package=@stoplight/prism-cli@~5.3.2 -- prism mock path/to/your.openapi.yml${NC}"
+  echo -e "  \$ ${YELLOW}npm exec --package=@stainless-api/prism-cli@5.15.0 -- prism mock path/to/your.openapi.yml${NC}"
   echo
 
   exit 1
diff --git a/scripts/utils/upload-artifact.sh b/scripts/utils/upload-artifact.sh
index ee0ba42e..8b5236df 100755
--- a/scripts/utils/upload-artifact.sh
+++ b/scripts/utils/upload-artifact.sh
@@ -1,7 +1,9 @@
 #!/usr/bin/env bash
 set -exuo pipefail
 
-RESPONSE=$(curl -X POST "$URL" \
+FILENAME=$(basename dist/*.whl)
+
+RESPONSE=$(curl -X POST "$URL?filename=$FILENAME" \
   -H "Authorization: Bearer $AUTH" \
   -H "Content-Type: application/json")
 
@@ -12,13 +14,13 @@ if [[ "$SIGNED_URL" == "null" ]]; then
   exit 1
 fi
 
-UPLOAD_RESPONSE=$(tar -cz . | curl -v -X PUT \
-  -H "Content-Type: application/gzip" \
-  --data-binary @- "$SIGNED_URL" 2>&1)
+UPLOAD_RESPONSE=$(curl -v -X PUT \
+  -H "Content-Type: binary/octet-stream" \
+  --data-binary "@dist/$FILENAME" "$SIGNED_URL" 2>&1)
 
 if echo "$UPLOAD_RESPONSE" | grep -q "HTTP/[0-9.]* 200"; then
   echo -e "\033[32mUploaded build to Stainless storage.\033[0m"
-  echo -e "\033[32mInstallation: pip install 'https://pkg.stainless.com/s/riza-api-python/$SHA'\033[0m"
+  echo -e "\033[32mInstallation: pip install 'https://pkg.stainless.com/s/riza-api-python/$SHA/$FILENAME'\033[0m"
 else
   echo -e "\033[31mFailed to upload artifact.\033[0m"
   exit 1
diff --git a/src/rizaio/_base_client.py b/src/rizaio/_base_client.py
index 8ac84196..e44d54b5 100644
--- a/src/rizaio/_base_client.py
+++ b/src/rizaio/_base_client.py
@@ -529,6 +529,18 @@ def _build_request(
             # work around https://github.com/encode/httpx/discussions/2880
             kwargs["extensions"] = {"sni_hostname": prepared_url.host.replace("_", "-")}
 
+        is_body_allowed = options.method.lower() != "get"
+
+        if is_body_allowed:
+            if isinstance(json_data, bytes):
+                kwargs["content"] = json_data
+            else:
+                kwargs["json"] = json_data if is_given(json_data) else None
+            kwargs["files"] = files
+        else:
+            headers.pop("Content-Type", None)
+            kwargs.pop("data", None)
+
         # TODO: report this error to httpx
         return self._client.build_request(  # pyright: ignore[reportUnknownMemberType]
             headers=headers,
@@ -540,8 +552,6 @@ def _build_request(
             # so that passing a `TypedDict` doesn't cause an error.
             # https://github.com/microsoft/pyright/issues/3526#event-6715453066
             params=self.qs.stringify(cast(Mapping[str, Any], params)) if params else None,
-            json=json_data if is_given(json_data) else None,
-            files=files,
             **kwargs,
         )
 
diff --git a/src/rizaio/_files.py b/src/rizaio/_files.py
index 715cc207..cc14c14f 100644
--- a/src/rizaio/_files.py
+++ b/src/rizaio/_files.py
@@ -69,12 +69,12 @@ def _transform_file(file: FileTypes) -> HttpxFileTypes:
         return file
 
     if is_tuple_t(file):
-        return (file[0], _read_file_content(file[1]), *file[2:])
+        return (file[0], read_file_content(file[1]), *file[2:])
 
     raise TypeError(f"Expected file types input to be a FileContent type or to be a tuple")
 
 
-def _read_file_content(file: FileContent) -> HttpxFileContent:
+def read_file_content(file: FileContent) -> HttpxFileContent:
     if isinstance(file, os.PathLike):
         return pathlib.Path(file).read_bytes()
     return file
@@ -111,12 +111,12 @@ async def _async_transform_file(file: FileTypes) -> HttpxFileTypes:
         return file
 
     if is_tuple_t(file):
-        return (file[0], await _async_read_file_content(file[1]), *file[2:])
+        return (file[0], await async_read_file_content(file[1]), *file[2:])
 
     raise TypeError(f"Expected file types input to be a FileContent type or to be a tuple")
 
 
-async def _async_read_file_content(file: FileContent) -> HttpxFileContent:
+async def async_read_file_content(file: FileContent) -> HttpxFileContent:
     if isinstance(file, os.PathLike):
         return await anyio.Path(file).read_bytes()
 
diff --git a/src/rizaio/_models.py b/src/rizaio/_models.py
index 4b399147..c9f0528d 100644
--- a/src/rizaio/_models.py
+++ b/src/rizaio/_models.py
@@ -2,9 +2,10 @@
 
 import os
 import inspect
-from typing import TYPE_CHECKING, Any, Type, Union, Generic, TypeVar, Callable, cast
+from typing import TYPE_CHECKING, Any, Type, Union, Generic, TypeVar, Callable, Optional, cast
 from datetime import date, datetime
 from typing_extensions import (
+    List,
     Unpack,
     Literal,
     ClassVar,
@@ -207,14 +208,18 @@ def construct(  # pyright: ignore[reportIncompatibleMethodOverride]
             else:
                 fields_values[name] = field_get_default(field)
 
+        extra_field_type = _get_extra_fields_type(__cls)
+
         _extra = {}
         for key, value in values.items():
             if key not in model_fields:
+                parsed = construct_type(value=value, type_=extra_field_type) if extra_field_type is not None else value
+
                 if PYDANTIC_V2:
-                    _extra[key] = value
+                    _extra[key] = parsed
                 else:
                     _fields_set.add(key)
-                    fields_values[key] = value
+                    fields_values[key] = parsed
 
         object.__setattr__(m, "__dict__", fields_values)
 
@@ -299,7 +304,7 @@ def model_dump(
                 exclude_none=exclude_none,
             )
 
-            return cast(dict[str, Any], json_safe(dumped)) if mode == "json" else dumped
+            return cast("dict[str, Any]", json_safe(dumped)) if mode == "json" else dumped
 
         @override
         def model_dump_json(
@@ -366,7 +371,24 @@ def _construct_field(value: object, field: FieldInfo, key: str) -> object:
     if type_ is None:
         raise RuntimeError(f"Unexpected field type is None for {key}")
 
-    return construct_type(value=value, type_=type_)
+    return construct_type(value=value, type_=type_, metadata=getattr(field, "metadata", None))
+
+
+def _get_extra_fields_type(cls: type[pydantic.BaseModel]) -> type | None:
+    if not PYDANTIC_V2:
+        # TODO
+        return None
+
+    schema = cls.__pydantic_core_schema__
+    if schema["type"] == "model":
+        fields = schema["schema"]
+        if fields["type"] == "model-fields":
+            extras = fields.get("extras_schema")
+            if extras and "cls" in extras:
+                # mypy can't narrow the type
+                return extras["cls"]  # type: ignore[no-any-return]
+
+    return None
 
 
 def is_basemodel(type_: type) -> bool:
@@ -420,7 +442,7 @@ def construct_type_unchecked(*, value: object, type_: type[_T]) -> _T:
     return cast(_T, construct_type(value=value, type_=type_))
 
 
-def construct_type(*, value: object, type_: object) -> object:
+def construct_type(*, value: object, type_: object, metadata: Optional[List[Any]] = None) -> object:
     """Loose coercion to the expected type with construction of nested values.
 
     If the given value does not match the expected type then it is returned as-is.
@@ -438,8 +460,10 @@ def construct_type(*, value: object, type_: object) -> object:
         type_ = type_.__value__  # type: ignore[unreachable]
 
     # unwrap `Annotated[T, ...]` -> `T`
-    if is_annotated_type(type_):
-        meta: tuple[Any, ...] = get_args(type_)[1:]
+    if metadata is not None and len(metadata) > 0:
+        meta: tuple[Any, ...] = tuple(metadata)
+    elif is_annotated_type(type_):
+        meta = get_args(type_)[1:]
         type_ = extract_type_arg(type_, 0)
     else:
         meta = tuple()
diff --git a/src/rizaio/_version.py b/src/rizaio/_version.py
index 02bdd107..64128762 100644
--- a/src/rizaio/_version.py
+++ b/src/rizaio/_version.py
@@ -1,4 +1,4 @@
 # File generated from our OpenAPI spec by Stainless. See CONTRIBUTING.md for details.
 
 __title__ = "rizaio"
-__version__ = "0.12.0"  # x-release-please-version
+__version__ = "0.13.0"  # x-release-please-version
diff --git a/tests/test_client.py b/tests/test_client.py
index 32de542b..fa6366f5 100644
--- a/tests/test_client.py
+++ b/tests/test_client.py
@@ -456,7 +456,7 @@ def test_request_extra_query(self) -> None:
     def test_multipart_repeating_array(self, client: Riza) -> None:
         request = client._build_request(
             FinalRequestOptions.construct(
-                method="get",
+                method="post",
                 url="/foo",
                 headers={"Content-Type": "multipart/form-data; boundary=6b7ba517decee4a450543ea6ae821c82"},
                 json_data={"array": ["foo", "bar"]},
@@ -1259,7 +1259,7 @@ def test_request_extra_query(self) -> None:
     def test_multipart_repeating_array(self, async_client: AsyncRiza) -> None:
         request = async_client._build_request(
             FinalRequestOptions.construct(
-                method="get",
+                method="post",
                 url="/foo",
                 headers={"Content-Type": "multipart/form-data; boundary=6b7ba517decee4a450543ea6ae821c82"},
                 json_data={"array": ["foo", "bar"]},
diff --git a/tests/test_models.py b/tests/test_models.py
index 70a35682..94710dd4 100644
--- a/tests/test_models.py
+++ b/tests/test_models.py
@@ -1,5 +1,5 @@
 import json
-from typing import Any, Dict, List, Union, Optional, cast
+from typing import TYPE_CHECKING, Any, Dict, List, Union, Optional, cast
 from datetime import datetime, timezone
 from typing_extensions import Literal, Annotated, TypeAliasType
 
@@ -889,3 +889,75 @@ class ModelB(BaseModel):
     )
 
     assert isinstance(m, ModelB)
+
+
+def test_nested_discriminated_union() -> None:
+    class InnerType1(BaseModel):
+        type: Literal["type_1"]
+
+    class InnerModel(BaseModel):
+        inner_value: str
+
+    class InnerType2(BaseModel):
+        type: Literal["type_2"]
+        some_inner_model: InnerModel
+
+    class Type1(BaseModel):
+        base_type: Literal["base_type_1"]
+        value: Annotated[
+            Union[
+                InnerType1,
+                InnerType2,
+            ],
+            PropertyInfo(discriminator="type"),
+        ]
+
+    class Type2(BaseModel):
+        base_type: Literal["base_type_2"]
+
+    T = Annotated[
+        Union[
+            Type1,
+            Type2,
+        ],
+        PropertyInfo(discriminator="base_type"),
+    ]
+
+    model = construct_type(
+        type_=T,
+        value={
+            "base_type": "base_type_1",
+            "value": {
+                "type": "type_2",
+            },
+        },
+    )
+    assert isinstance(model, Type1)
+    assert isinstance(model.value, InnerType2)
+
+
+@pytest.mark.skipif(not PYDANTIC_V2, reason="this is only supported in pydantic v2 for now")
+def test_extra_properties() -> None:
+    class Item(BaseModel):
+        prop: int
+
+    class Model(BaseModel):
+        __pydantic_extra__: Dict[str, Item] = Field(init=False)  # pyright: ignore[reportIncompatibleVariableOverride]
+
+        other: str
+
+        if TYPE_CHECKING:
+
+            def __getattr__(self, attr: str) -> Item: ...
+
+    model = construct_type(
+        type_=Model,
+        value={
+            "a": {"prop": 1},
+            "other": "foo",
+        },
+    )
+    assert isinstance(model, Model)
+    assert model.a.prop == 1
+    assert isinstance(model.a, Item)
+    assert model.other == "foo"