diff --git a/pyproject.toml b/pyproject.toml
index 737ce4e1e..5ea398af6 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -3,7 +3,7 @@ name = "cohere"
 
 [tool.poetry]
 name = "cohere"
-version = "5.13.7"
+version = "5.13.8"
 description = ""
 readme = "README.md"
 authors = []
diff --git a/src/cohere/core/client_wrapper.py b/src/cohere/core/client_wrapper.py
index 791c32b06..22e02d077 100644
--- a/src/cohere/core/client_wrapper.py
+++ b/src/cohere/core/client_wrapper.py
@@ -24,7 +24,7 @@ def get_headers(self) -> typing.Dict[str, str]:
         headers: typing.Dict[str, str] = {
             "X-Fern-Language": "Python",
             "X-Fern-SDK-Name": "cohere",
-            "X-Fern-SDK-Version": "5.13.7",
+            "X-Fern-SDK-Version": "5.13.8",
         }
         if self._client_name is not None:
             headers["X-Client-Name"] = self._client_name
diff --git a/src/cohere/types/document.py b/src/cohere/types/document.py
index a18e03569..167aa5b80 100644
--- a/src/cohere/types/document.py
+++ b/src/cohere/types/document.py
@@ -13,9 +13,9 @@ class Document(UncheckedBaseModel):
     passed to the model.
     """
 
-    data: typing.Dict[str, str] = pydantic.Field()
+    data: typing.Dict[str, typing.Optional[typing.Any]] = pydantic.Field()
     """
-    A relevant documents that the model can cite to generate a more accurate reply. Each document is a string-string dictionary.
+    A relevant document that the model can cite to generate a more accurate reply. Each document is a string-any dictionary.
     """
 
     id: typing.Optional[str] = pydantic.Field(default=None)
diff --git a/tests/test_async_client.py b/tests/test_async_client.py
index 187d8d53b..aa1e9c7a2 100644
--- a/tests/test_async_client.py
+++ b/tests/test_async_client.py
@@ -331,7 +331,7 @@ async def test_tool_use(self) -> None:
         ]
 
         tool_parameters_response = await self.co.chat(
-            message="How good were the sales on September 29?",
+            message="How good were the sales on September 29 2023?",
             tools=tools,
             model="command-nightly",
             preamble="""
diff --git a/tests/test_client.py b/tests/test_client.py
index 9a839877e..c42245feb 100644
--- a/tests/test_client.py
+++ b/tests/test_client.py
@@ -393,7 +393,7 @@ def test_tool_use(self) -> None:
         ]
 
         tool_parameters_response = co.chat(
-            message="How good were the sales on September 29?",
+            message="How good were the sales on September 29 2023?",
             tools=tools,
             model="command-nightly",
             preamble="""