diff --git a/aider/coders/chat_chunks.py b/aider/coders/chat_chunks.py
index e69de29bb..9d1360604 100644
--- a/aider/coders/chat_chunks.py
+++ b/aider/coders/chat_chunks.py
@@ -0,0 +1,53 @@
+from dataclasses import dataclass, field
+from typing import List
+
+
+@dataclass
+class ChatChunks:
+    system: List = field(default_factory=list)
+    examples: List = field(default_factory=list)
+    done: List = field(default_factory=list)
+    repo: List = field(default_factory=list)
+    readonly_files: List = field(default_factory=list)
+    chat_files: List = field(default_factory=list)
+    cur: List = field(default_factory=list)
+    reminder: List = field(default_factory=list)
+
+    def all_messages(self):
+        return (
+            self.system
+            + self.examples
+            + self.readonly_files
+            + self.repo
+            + self.done
+            + self.chat_files
+            + self.cur
+            + self.reminder
+        )
+
+    def add_cache_control_headers(self):
+        if self.examples:
+            self.add_cache_control(self.examples)
+        else:
+            self.add_cache_control(self.system)
+
+        if self.readonly_files:
+            self.add_cache_control(self.readonly_files)
+        else:
+            self.add_cache_control(self.repo)
+
+        self.add_cache_control(self.chat_files)
+
+    def add_cache_control(self, messages):
+        if not messages:
+            return
+
+        content = messages[-1]["content"]
+        if type(content) is str:
+            content = dict(
+                type="text",
+                text=content,
+            )
+        content["cache_control"] = {"type": "ephemeral"}
+
+        messages[-1]["content"] = [content]