diff --git a/packages/mosaic/framework/tools/git/pr-review.sh b/packages/mosaic/framework/tools/git/pr-review.sh
index 0eb717ec..c5e9028b 100755
--- a/packages/mosaic/framework/tools/git/pr-review.sh
+++ b/packages/mosaic/framework/tools/git/pr-review.sh
@@ -124,6 +124,13 @@ case "$ACTION" in
     *) usage_error "unknown action '$ACTION': approve, request-changes, comment" ;;
 esac
 
+# Body-required actions fail fast too (codex follow-up on PR #1464):
+# request-changes and comment both require a body; validate before any
+# provider contact.
+if [[ ( "$ACTION" == "request-changes" || "$ACTION" == "comment" ) && -z "$COMMENT" ]]; then
+    usage_error "comment required for $ACTION (-b/--body)"
+fi
+
 if [[ -n "$REPO_OVERRIDE" ]]; then
     # An explicit --repo is the whole point of a reviewer worktree whose origin
     # is nonstandard or missing (#867 convention, mirrored from pr-view.sh /
diff --git a/packages/mosaic/framework/tools/git/test-pr-review-repo-host-override.sh b/packages/mosaic/framework/tools/git/test-pr-review-repo-host-override.sh
index f5699ce4..789fa410 100755
--- a/packages/mosaic/framework/tools/git/test-pr-review-repo-host-override.sh
+++ b/packages/mosaic/framework/tools/git/test-pr-review-repo-host-override.sh
@@ -218,7 +218,7 @@ if grep -q 'Unknown option' "$OUTPUT_FILE"; then
     cat "$OUTPUT_FILE" >&2
     exit 1
 fi
-grep -q 'Unknown action: bogus-action' "$OUTPUT_FILE"
+grep -q "unknown action 'bogus-action'" "$OUTPUT_FILE"
 
 # --- Case 2: -h/--help documents both overrides.
 HELP_TEXT="$("$SCRIPT_DIR/pr-review.sh" -h)"
diff --git a/packages/mosaic/framework/tools/git/test-pr-review-usage-contract.sh b/packages/mosaic/framework/tools/git/test-pr-review-usage-contract.sh
index 1c4f8d69..a66b2075 100755
--- a/packages/mosaic/framework/tools/git/test-pr-review-usage-contract.sh
+++ b/packages/mosaic/framework/tools/git/test-pr-review-usage-contract.sh
@@ -97,6 +97,8 @@ expect_rc 2 "missing -a exits 2" -n 5
 expect_stderr "Action is required" "missing -a message on stderr"
 expect_rc 2 "request-changes without comment exits 2" -n 5 -a request-changes
 expect_stderr "comment required for request-changes" "request-changes message on stderr"
+expect_rc 2 "comment without body exits 2 pre-detection" -n 5 -a comment
+expect_stderr "comment required for comment" "comment-without-body message on stderr"
 expect_rc 2 "invalid action exits 2 pre-detection" -n 5 -a bogus
 expect_stderr "unknown action" "invalid action message on stderr"
 # Invalid-action arms must not contact any provider (validation precedes