diff --git a/nanobot/providers/openai_compat_provider.py b/nanobot/providers/openai_compat_provider.py
index 4fa057b90..132f05a28 100644
--- a/nanobot/providers/openai_compat_provider.py
+++ b/nanobot/providers/openai_compat_provider.py
@@ -21,6 +21,7 @@ if TYPE_CHECKING:
 
 _ALLOWED_MSG_KEYS = frozenset({
     "role", "content", "tool_calls", "tool_call_id", "name",
+    "reasoning_content", "extra_content",
 })
 _ALNUM = string.ascii_letters + string.digits
 
diff --git a/nanobot/session/manager.py b/nanobot/session/manager.py
index 95e3916b9..27df31405 100644
--- a/nanobot/session/manager.py
+++ b/nanobot/session/manager.py
@@ -54,7 +54,7 @@ class Session:
         out: list[dict[str, Any]] = []
         for message in sliced:
             entry: dict[str, Any] = {"role": message["role"], "content": message.get("content", "")}
-            for key in ("tool_calls", "tool_call_id", "name"):
+            for key in ("tool_calls", "tool_call_id", "name", "reasoning_content"):
                 if key in message:
                     entry[key] = message[key]
             out.append(entry)