diff --git a/pyproject.toml b/pyproject.toml
index 454d8fd..7c2908f 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -39,7 +39,7 @@ Homepage = "https://github.com/sst/opencode-sdk-python"
 Repository = "https://github.com/sst/opencode-sdk-python"
 
 [project.optional-dependencies]
-aiohttp = ["aiohttp", "httpx_aiohttp>=0.1.6"]
+aiohttp = ["aiohttp", "httpx_aiohttp>=0.1.8"]
 
 [tool.rye]
 managed = true
diff --git a/src/opencode_ai/_base_client.py b/src/opencode_ai/_base_client.py
index f7025f4..f52a9ac 100644
--- a/src/opencode_ai/_base_client.py
+++ b/src/opencode_ai/_base_client.py
@@ -529,6 +529,15 @@ class BaseClient(Generic[_HttpxClientT, _DefaultStreamT]):
             # 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:
+            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 +549,6 @@ class BaseClient(Generic[_HttpxClientT, _DefaultStreamT]):
             # 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/tests/test_client.py b/tests/test_client.py
index 0cf7c41..5fb4ca7 100644
--- a/tests/test_client.py
+++ b/tests/test_client.py
@@ -428,7 +428,7 @@ class TestOpencode:
     def test_multipart_repeating_array(self, client: Opencode) -> 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"]},
@@ -1203,7 +1203,7 @@ class TestAsyncOpencode:
     def test_multipart_repeating_array(self, async_client: AsyncOpencode) -> 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"]},