diff --git a/aider/coders/base_coder.py b/aider/coders/base_coder.py
index f3cb8923a..f6c3267dd 100755
--- a/aider/coders/base_coder.py
+++ b/aider/coders/base_coder.py
@@ -1031,7 +1031,7 @@ class Coder:
         if self.partial_response_function_call:
             args = self.parse_partial_args()
             if args:
-                content = args["explanation"]
+                content = args.get("explanation") or ""
             else:
                 content = ""
         elif self.partial_response_content:
diff --git a/aider/coders/single_wholefile_func_coder.py b/aider/coders/single_wholefile_func_coder.py
index 290969180..87cf9bf41 100644
--- a/aider/coders/single_wholefile_func_coder.py
+++ b/aider/coders/single_wholefile_func_coder.py
@@ -1,5 +1,3 @@
-import json
-
 from aider import diffs
 
 from ..dump import dump  # noqa: F401
@@ -14,9 +12,9 @@ class SingleWholeFileFunctionCoder(Coder):
         dict(
             name="write_file",
             description="write new content into the file",
+            strict=True,
             parameters=dict(
                 type="object",
-                required=["explanation", "content"],
                 properties=dict(
                     explanation=dict(
                         type="string",
@@ -27,9 +25,11 @@ class SingleWholeFileFunctionCoder(Coder):
                     ),
                     content=dict(
                         type="string",
-                        description="Content to write to the file",
+                        # description="Content to write to the file",
                     ),
                 ),
+                required=["explanation", "content"],
+                additionalProperties=False,
             ),
         ),
     ]
diff --git a/aider/sendchat.py b/aider/sendchat.py
index 16e296ebf..e45444ef9 100644
--- a/aider/sendchat.py
+++ b/aider/sendchat.py
@@ -59,7 +59,7 @@ def send_completion(
     )
 
     if functions is not None:
-        kwargs["tools"] = [dict(type="functions", function=functions[0])]
+        kwargs["tools"] = [dict(type="function", function=functions[0])]
     if extra_headers is not None:
         kwargs["extra_headers"] = extra_headers
     if max_tokens is not None: