diff --git a/README.md b/README.md
index 1ae68e7..45d1eaa 100644
--- a/README.md
+++ b/README.md
@@ -40,6 +40,11 @@ The global mode sets `git config --global core.hooksPath ~/.config/git/hooks`. S
 its own local `core.hooksPath` overrides the global hook — install per-repo there. See memory
 `reference_global_security_review_hook`.
 
+- `--global` also creates the machine-level suppressions dir
+  (`${SH_SECURITY_SUPPRESSIONS_DIR:-~/.config/sea-haven/security-review}`): the per-repo file
+  `<dir>/<repo-basename>/suppressions.json` is preferred by the hooks over repo-local
+  `.security-review/suppressions.json`, and `review.sh` merges both when run without `--suppressions`.
+
 **Suppressing a false positive.** A written justification is required and is surfaced in the report.
 When no `--suppressions FILE` is passed, `review.sh` auto-resolves and **merges** suppressions from
 two locations (an explicit `--suppressions` still overrides both):
diff --git a/install-hooks.sh b/install-hooks.sh
index 6a10a78..42ed933 100755
--- a/install-hooks.sh
+++ b/install-hooks.sh
@@ -18,6 +18,7 @@ set -euo pipefail
 SRC="$(cd "$(dirname "$0")" && pwd)"
 GLOBAL_HOOKS="$HOME/.config/git/hooks"
 CLAUDE_DIR="$HOME/.claude"
+SUP_DIR="${SH_SECURITY_SUPPRESSIONS_DIR:-$HOME/.config/sea-haven/security-review}"
 
 usage() { grep '^#' "$0" | sed 's/^# \{0,1\}//'; }
 
@@ -40,6 +41,9 @@ case "${1:-}" in
   --global)
     echo "== Installing Sea Haven security-review hooks globally =="
     mkdir -p "$GLOBAL_HOOKS"
+    mkdir -p "$SUP_DIR"
+    echo "  suppressions: machine-level per-repo file $SUP_DIR/<repo-basename>/suppressions.json is preferred by the hooks over repo-local .security-review/suppressions.json"
+    echo "  suppressions: review.sh merges both locations when run without --suppressions"
 
     # Warn (don't clobber silently) if a different global hooksPath is already set.
     CURRENT="$(git config --global --get core.hooksPath || true)"