diff --git a/.githooks/commit-msg b/.githooks/commit-msg
index c8d3100..d869c66 100755
--- a/.githooks/commit-msg
+++ b/.githooks/commit-msg
@@ -1,6 +1,9 @@
 #!/bin/sh
-# Reject any AI attribution in commit messages.
-if grep -qiE 'claude|anthropic|co-authored-by|generated with|ai-assisted' "$1"; then
+# Reject AI attribution in commit messages (Claude/Anthropic/"generated with"/
+# "ai-assisted"). Plain Co-authored-by trailers are allowed: GitHub adds them on
+# squash-merge and for Dependabot, and an AI co-author is still caught by the
+# name patterns above.
+if grep -qiE 'claude|anthropic|generated with|ai-assisted' "$1"; then
   echo "commit-msg hook: forbidden attribution pattern found. Rewrite the message." >&2
   exit 1
 fi
diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index c343d70..6357201 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -64,11 +64,13 @@ jobs:
         with:
           fetch-depth: 0
       # CI mirror of .githooks/commit-msg: scan every commit message in
-      # the repository for forbidden attribution patterns.
+      # the repository for AI attribution. Plain Co-authored-by trailers are
+      # allowed (GitHub adds them on squash-merge and for Dependabot); an AI
+      # co-author is still caught by the name patterns.
       - name: audit commit messages
         run: |
           set -eu
-          pattern='claude|anthropic|co-authored-by|generated with|ai-assisted'
+          pattern='claude|anthropic|generated with|ai-assisted'
           matches=$(git log --format='%H %s %b' | grep -icE "$pattern" || true)
           if [ "$matches" -ne 0 ]; then
             echo "commit-audit: forbidden attribution pattern found in commit messages:" >&2