diff --git a/reginaldCog/openai/content_builder.py b/reginaldCog/openai/content_builder.py
index cc18a04..a75aabd 100644
--- a/reginaldCog/openai/content_builder.py
+++ b/reginaldCog/openai/content_builder.py
@@ -1,7 +1,7 @@
 from dataclasses import dataclass, field, fields
 
 
-@dataclass
+@dataclass(frozen=True)
 class Content:
     type: str = field(init=False, default='')
 
@@ -30,19 +30,19 @@ class Content:
         return result
 
 
-@dataclass
+@dataclass(frozen=True)
 class InputText(Content):
     type: str = field(init=False, default='input_text')
     text: str
 
 
-@dataclass
+@dataclass(frozen=True)
 class OutputText(Content):
     type: str = field(init=False, default='output_text')
     text: str
 
 
-@dataclass
+@dataclass(frozen=True)
 class InputImage(Content):
     type: str = field(init=False, default='input_image')
     image_url: str = field(default=None)
@@ -53,12 +53,12 @@ class InputImage(Content):
             raise ValueError("Either 'image_url' or 'file_id' must be provided.")
 
 
-@dataclass
+@dataclass(frozen=True)
 class UrlCitation(Content):
     pass
 
 
-@dataclass
+@dataclass(frozen=True)
 class FunctionCall(Content):
     type: str = field(init=False, default='function_call')
     id: str
@@ -67,7 +67,7 @@ class FunctionCall(Content):
     arguments: dict
 
 
-@dataclass
+@dataclass(frozen=True)
 class FunctionCallOutput(Content):
     type: str = field(init=False, default='function_call_output')
     call_id: str
diff --git a/reginaldCog/openai/message_builder.py b/reginaldCog/openai/message_builder.py
index 2ab3cd0..2585cd9 100644
--- a/reginaldCog/openai/message_builder.py
+++ b/reginaldCog/openai/message_builder.py
@@ -2,7 +2,7 @@ from dataclasses import dataclass
 from content_builder import Content, InputText, InputImage
 
 
-@dataclass
+@dataclass(frozen=True)
 class Message:
     role: str
     content: list[Content]