diff --git a/aider/prompts.py b/aider/prompts.py
index 27d833fdd..8e26338ee 100644
--- a/aider/prompts.py
+++ b/aider/prompts.py
@@ -10,12 +10,13 @@ one-line Git commit messages based on the provided diffs.
 Review the provided context and diffs which are about to be committed to a git repo.
 Review the diffs carefully.
 Generate a one-line commit message for those changes.
+The commit message should be entirely lowercase.
 The commit message should be structured as follows: <type>: <description>
 Use these for <type>: fix, feat, build, chore, ci, docs, style, refactor, perf, test
 
 Ensure the commit message:
 - Starts with the appropriate prefix.
-- Is in the imperative mood (e.g., \"Add feature\" not \"Added feature\" or \"Adding feature\").
+- Is in the imperative mood (e.g., \"add feature\" not \"added feature\" or \"adding feature\").
 - Does not exceed 72 characters.
 
 Reply only with the one-line commit message, without any additional text, explanations, \