diff --git a/.agent/rules.md b/.agent/rules.md
new file mode 100644
index 0000000..634c21c
--- /dev/null
+++ b/.agent/rules.md
@@ -0,0 +1,5 @@
+# Antigravity Agent Configuration
+# This file provides global rules for the Antigravity agent when working on this repository.
+
+- **Git Commits**: When making git commits, always append the following co-author trailer to the end of the commit message to indicate AI assistance:
+  `Co-authored-by: Antigravity <antigravity@deepmind.com>`
diff --git a/CLAUDE.md b/CLAUDE.md
index 5b387e4..620d72c 100644
--- a/CLAUDE.md
+++ b/CLAUDE.md
@@ -25,3 +25,8 @@ Once a tech stack is chosen and implementation begins, update this file with:
 - Build, test, and lint commands
 - Architecture overview
 - Development setup instructions
+
+## Git Commits
+
+When making git commits, always append the following co-author trailer to the end of the commit message to indicate AI assistance:
+`Co-authored-by: Antigravity <antigravity@deepmind.com>`