diff --git a/aider/coders/base_coder.py b/aider/coders/base_coder.py
index d0397d85f..16774cac7 100755
--- a/aider/coders/base_coder.py
+++ b/aider/coders/base_coder.py
@@ -95,6 +95,9 @@ class Coder:
         stream=True,
         use_git=True,
     ):
+        if not fnames:
+            fnames = []
+
         self.verbose = verbose
         self.abs_fnames = set()
         self.cur_messages = []
diff --git a/aider/coders/wholefile_coder.py b/aider/coders/wholefile_coder.py
index bcba5060b..92c166354 100644
--- a/aider/coders/wholefile_coder.py
+++ b/aider/coders/wholefile_coder.py
@@ -28,14 +28,12 @@ class WholeFileCoder(Coder):
 
         edited = set()
         chat_files = self.get_inchat_relative_files()
-        if not chat_files:
-            if mode == "diff":
-                return content
-            return
 
         output = []
         lines = content.splitlines(keepends=True)
 
+        allowed_to_edit = False
+
         fname = None
         new_lines = []
         for i, line in enumerate(lines):
@@ -55,10 +53,11 @@ class WholeFileCoder(Coder):
                         ).splitlines()
                         output += show_diff
                     else:
-                        edited.add(fname)
-                        if not self.dry_run:
-                            new_lines = "".join(new_lines)
-                            Path(full_path).write_text(new_lines)
+                        if allowed_to_edit:
+                            edited.add(fname)
+                            if not self.dry_run:
+                                new_lines = "".join(new_lines)
+                                Path(full_path).write_text(new_lines)
 
                     fname = None
                     new_lines = []
@@ -74,8 +73,11 @@ class WholeFileCoder(Coder):
                 else:
                     fname = lines[i - 1].strip()
 
-                if mode == "update" and not self.allowed_to_edit(fname):
-                    raise ValueError(f"{fname} is not one of: {show_chat_files}")
+                if mode == "update":
+                    if self.allowed_to_edit(fname):
+                        allowed_to_edit = True
+                    else:
+                        allowed_to_edit = False
 
             elif fname:
                 new_lines.append(line)
diff --git a/aider/coders/wholefile_prompts.py b/aider/coders/wholefile_prompts.py
index e93412d95..2882d4dcb 100644
--- a/aider/coders/wholefile_prompts.py
+++ b/aider/coders/wholefile_prompts.py
@@ -14,14 +14,20 @@ Once you understand the request you MUST:
 3. If changes are needed, output a copy of each file that needs changes.
 """
 
-    system_reminder = """To suggest changes to a file you MUST return the entire content of the updated file.
-You MUST use this format:
+    system_reminder = """
+To return code you MUST use this *file listing* format:
 
 exact/path/to/filename.js
 ```javascript
 // file content goes in the
 // triple backticked fenced block
 ```
+
+Every *file listing* must start with the full path!
+Every *file listing* must be fenced w/triple backticks with the correct code language.
+
+To suggest changes to a file you MUST return a *file listing* that contains the entire content of the file.
+Create a new file you MUST return a *file listing* which includes an appropriate path/filename.
 """
 
     files_content_prefix = "Here is the current content of the files:\n"
diff --git a/tests/test_wholefile.py b/tests/test_wholefile.py
index 5b69adb13..9f77d33ee 100644
--- a/tests/test_wholefile.py
+++ b/tests/test_wholefile.py
@@ -41,6 +41,33 @@ class TestWholeFileCoder(unittest.TestCase):
                 updated_content = f.read()
             self.assertEqual(updated_content, "Updated content\n")
 
+    def test_update_files_not_in_chat(self):
+        with tempfile.TemporaryDirectory() as temp_dir:
+            os.chdir(temp_dir)
+
+            # Create a sample file in the temporary directory
+            sample_file = "sample.txt"
+            with open(sample_file, "w") as f:
+                f.write("Original content\n")
+
+            # Initialize WholeFileCoder with the temporary directory
+            io = InputOutput(yes=True)
+            coder = WholeFileCoder(main_model=models.GPT35, io=io)
+
+            # Set the partial response content with the updated content
+            coder.partial_response_content = f"{sample_file}\n```\nUpdated content\n```"
+
+            # Call update_files method
+            edited_files = coder.update_files()
+
+            # Check if the sample file was updated
+            self.assertIn("sample.txt", edited_files)
+
+            # Check if the content of the sample file was updated
+            with open(sample_file, "r") as f:
+                updated_content = f.read()
+            self.assertEqual(updated_content, "Updated content\n")
+
 
 if __name__ == "__main__":
     unittest.main()