diff --git a/aider/args.py b/aider/args.py
index 716bca4f8..070905bb4 100644
--- a/aider/args.py
+++ b/aider/args.py
@@ -21,11 +21,17 @@ def get_parser(default_config_files, git_root):
         auto_env_var_prefix="AIDER_",
     )
     group = parser.add_argument_group("Main")
+    group.add_argument(
+        "--llm-history-file",
+        metavar="LLM_HISTORY_FILE",
+        default=None,
+        help="Log the conversation with the LLM to this file (for example, .aider.llm.history)",
+    )
     group.add_argument(
         "files",
         metavar="FILE",
         nargs="*",
-        help="files to edit with an LLM (optional)",
+        help="files to edit with an LLM (optional)"
     )
     group.add_argument(
         "--openai-api-key",
diff --git a/aider/coders/base_coder.py b/aider/coders/base_coder.py
index b704841fa..255451e28 100755
--- a/aider/coders/base_coder.py
+++ b/aider/coders/base_coder.py
@@ -1,5 +1,6 @@
 #!/usr/bin/env python
 
+import datetime
 import hashlib
 import json
 import os
@@ -27,7 +28,7 @@ from aider.mdstream import MarkdownStream
 from aider.repo import GitRepo
 from aider.repomap import RepoMap
 from aider.sendchat import send_with_retries
-from aider.utils import is_image_file
+from aider.utils import is_image_file, format_messages, format_content
 
 from ..dump import dump  # noqa: F401
 
@@ -783,6 +784,8 @@ class Coder:
 
         messages = self.format_messages()
 
+        self.io.log_llm_history("TO LLM", format_messages(messages))
+
         if self.verbose:
             utils.show_messages(messages, functions=self.functions)
 
@@ -805,6 +808,9 @@ class Coder:
                 exhausted = True
             else:
                 raise err
+        except Exception as err:
+            self.io.tool_error(f"Unexpected error: {err}")
+            return
 
         if exhausted:
             self.show_exhausted_error()
@@ -824,6 +830,8 @@ class Coder:
 
         self.io.tool_output()
 
+        self.io.log_llm_history("LLM RESPONSE", format_content("ASSISTANT", content))
+
         if interrupted:
             content += "\n^C KeyboardInterrupt"
             self.cur_messages += [dict(role="assistant", content=content)]
diff --git a/aider/io.py b/aider/io.py
index 65093332c..1cf09f41f 100644
--- a/aider/io.py
+++ b/aider/io.py
@@ -107,6 +107,7 @@ class InputOutput:
         tool_error_color="red",
         encoding="utf-8",
         dry_run=False,
+        llm_history_file=None,
         editingmode=EditingMode.EMACS,
     ):
         self.editingmode = editingmode
@@ -128,6 +129,7 @@ class InputOutput:
         self.yes = yes
 
         self.input_history_file = input_history_file
+        self.llm_history_file = llm_history_file
         if chat_history_file is not None:
             self.chat_history_file = Path(chat_history_file)
         else:
@@ -209,10 +211,11 @@ class InputOutput:
         else:
             style = None
 
+        completer_instance = AutoCompleter(
+            root, rel_fnames, addable_rel_fnames, commands, self.encoding
+        )
+
         while True:
-            completer_instance = AutoCompleter(
-                root, rel_fnames, addable_rel_fnames, commands, self.encoding
-            )
             if multiline_input:
                 show = ". "
 
@@ -271,6 +274,14 @@ class InputOutput:
         fh = FileHistory(self.input_history_file)
         return fh.load_history_strings()
 
+    def log_llm_history(self, role, content):
+        if not self.llm_history_file:
+            return
+        timestamp = datetime.now().isoformat(timespec='seconds')
+        with open(self.llm_history_file, 'a', encoding=self.encoding) as log_file:
+            log_file.write(f"{role.upper()} {timestamp}\n")
+            log_file.write(content + "\n")
+
     def user_input(self, inp, log_only=True):
         if not log_only:
             style = dict(style=self.user_input_color) if self.user_input_color else dict()
diff --git a/aider/main.py b/aider/main.py
index 79c1511d8..c4d211fc7 100644
--- a/aider/main.py
+++ b/aider/main.py
@@ -261,6 +261,7 @@ def main(argv=None, input=None, output=None, force_git_root=None, return_coder=F
         tool_error_color=args.tool_error_color,
         dry_run=args.dry_run,
         encoding=args.encoding,
+        llm_history_file=args.llm_history_file,
         editingmode=editing_mode,
     )
 
diff --git a/aider/utils.py b/aider/utils.py
index 31767aec6..7636eb119 100644
--- a/aider/utils.py
+++ b/aider/utils.py
@@ -84,24 +84,38 @@ def safe_abs_path(res):
     return str(res)
 
 
-def show_messages(messages, title=None, functions=None):
+def format_content(role, content):
+    formatted_lines = []
+    for line in content.splitlines():
+        formatted_lines.append(f"{role} {line}")
+    return "\n".join(formatted_lines)
+
+
+def format_messages(messages, title=None):
+    output = []
     if title:
-        print(title.upper(), "*" * 50)
+        output.append(f"{title.upper()} {'*' * 50}")
 
     for msg in messages:
-        print()
+        output.append("")
         role = msg["role"].upper()
         content = msg.get("content")
         if isinstance(content, list):  # Handle list content (e.g., image messages)
             for item in content:
                 if isinstance(item, dict) and "image_url" in item:
-                    print(role, "Image URL:", item["image_url"]["url"])
+                    output.append(f"{role} Image URL: {item['image_url']['url']}")
         elif isinstance(content, str):  # Handle string content
-            for line in content.splitlines():
-                print(role, line)
+            output.append(format_content(role, content))
         content = msg.get("function_call")
         if content:
-            print(role, content)
+            output.append(f"{role} {content}")
+
+    return "\n".join(output)
+
+
+def show_messages(messages, title=None, functions=None):
+    formatted_output = format_messages(messages, title)
+    print(formatted_output)
 
     if functions:
         dump(functions)