diff --git a/.dirsize-baseline b/.dirsize-baseline
new file mode 100644
index 0000000..4c0e15c
--- /dev/null
+++ b/.dirsize-baseline
@@ -0,0 +1,8 @@
+# Directory-size baseline (docs/patterns/07) - flat SOURCE-file counts > 15
+# that are tolerated until split (ratchet: may only shrink, never grow; a NEW
+# oversized directory fails `check-directory-size.sh --gate`). This file IS the
+# god-folder whitelist. components/ is the EXAMPLE-DOMAIN demo surface and
+# shrinks naturally as you replace the example domain with your own.
+# Format: <path>  # reason
+frontend/src/components   # EXAMPLE-DOMAIN demo components (shrinks on customization)
+frontend/src/hooks        # shared hooks
diff --git a/Makefile b/Makefile
index db66827..69ab78b 100644
--- a/Makefile
+++ b/Makefile
@@ -14,6 +14,7 @@
        audit-backend audit-frontend bandit-backend security-backend check-security \
        release-prepare release-finish release-publish \
        check-file-sizes check-complexity check-complexity-gate check-complexity-gate-update \
+       check-directory-size check-directory-size-gate \
        clean prod prod-down prod-logs help
 
 # --- Development ---
@@ -276,6 +277,12 @@ check-complexity-gate: ## Complexity ratchet gate: fail on new/regressed offende
 check-complexity-gate-update: ## Regenerate .complexity-baseline from current offenders (ratchet may only shrink)
 	@bash scripts/check-complexity.sh --update-baseline
 
+check-directory-size: ## God-folder watcher (warn-only): >15 flat source files per dir under frontend/src
+	@bash scripts/check-directory-size.sh
+
+check-directory-size-gate: ## God-folder ratchet gate: fail on a NEW oversized dir vs .dirsize-baseline
+	@bash scripts/check-directory-size.sh --gate
+
 # --- E2E Tests ---
 
 test-e2e: ## Run Playwright e2e tests (starts servers automatically)
diff --git a/docs/patterns/07-complexity-cohesion-ratchet.md b/docs/patterns/07-complexity-cohesion-ratchet.md
index 16d60ac..02e010f 100644
--- a/docs/patterns/07-complexity-cohesion-ratchet.md
+++ b/docs/patterns/07-complexity-cohesion-ratchet.md
@@ -8,10 +8,12 @@
 `radon_warn.py` / `complexity_gate.py`), with `make check-file-sizes` /
 `check-complexity` / `check-complexity-gate` / `check-complexity-gate-update`
 and shrink-only `.filesize-baseline` + `.complexity-baseline` (plus a
-`.filesize-whitelist`). radon is a backend dev-dependency. The **TypeScript
-(eslint) half of the complexity gate degrades gracefully** and is inactive
-until the template has an ESLint flat config (`eslint.config.js`); the
-**god-folder watcher** is still documented-only - add it as below.
+`.filesize-whitelist`). radon is a backend dev-dependency. The **god-folder
+watcher** also ships - `scripts/check-directory-size.sh` + `make
+check-directory-size` / `check-directory-size-gate` with a shrink-only
+`.dirsize-baseline`. The only remaining gap is the **TypeScript (eslint) half
+of the complexity gate**, which degrades gracefully and stays inactive until
+the template has an ESLint flat config (`eslint.config.js`).
 
 ---
 
diff --git a/scripts/check-directory-size.sh b/scripts/check-directory-size.sh
new file mode 100644
index 0000000..a2734ce
--- /dev/null
+++ b/scripts/check-directory-size.sh
@@ -0,0 +1,72 @@
+#!/usr/bin/env bash
+# check-directory-size.sh - god-folder watcher (docs/patterns/07).
+#
+# Counts the FLAT (maxdepth 1) source files (*.ts / *.tsx, tests excluded) in
+# each directory under frontend/src and warns when a directory holds too many.
+# Like the file-size watcher, this prevents god-folders from returning after
+# they were grouped by concern.
+#
+# Two modes:
+#   (default)  WARN_THRESHOLD (default 15) - warn, no fail.
+#   --gate     exit 1 when a directory NOT listed in .dirsize-baseline is over
+#              the threshold (ratchet: existing, not-yet-split god-folders are
+#              tolerated, but a NEW one fails).
+#
+# Only version-controlled sources under frontend/src (git ls-files), so
+# generated / gitignored trees drop out automatically.
+#
+# Exit codes:
+#   0 = clean, warnings only, or only tolerated baseline directories
+#   1 = (only with --gate) a new directory over the threshold
+
+set -euo pipefail
+
+WARN_THRESHOLD="${WARN_THRESHOLD:-15}"
+ROOT_DIR="${ROOT_DIR:-frontend/src}"
+BASELINE_FILE=".dirsize-baseline"
+
+SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+REPO_ROOT="$(cd "$SCRIPT_DIR/.." && pwd)"
+cd "$REPO_ROOT"
+
+GATE=0
+[[ "${1:-}" == "--gate" ]] && GATE=1
+
+# Tolerated (not-yet-split) directories, one path per line, '#' comments ok.
+declare -A BASELINE=()
+if [[ -f "$BASELINE_FILE" ]]; then
+    while IFS= read -r line; do
+        line="${line%%#*}"; line="$(echo -n "$line" | xargs || true)"
+        [[ -n "$line" ]] && BASELINE["$line"]=1
+    done < "$BASELINE_FILE"
+fi
+
+# Count flat (maxdepth 1) tracked *.ts/*.tsx per directory. Co-located test
+# files (*.test.ts/x) are excluded: the guard is about grouping SOURCE files
+# by concern, and tests live next to their subject by convention.
+declare -A COUNT=()
+while IFS= read -r f; do
+    [[ "$f" == */* ]] || continue
+    case "$f" in *.test.ts|*.test.tsx) continue;; esac
+    dir="${f%/*}"
+    COUNT["$dir"]=$(( ${COUNT["$dir"]:-0} + 1 ))
+done < <(git ls-files "$ROOT_DIR" | grep -E '\.tsx?$' || true)
+
+status=0
+warned=0
+for dir in $(printf '%s\n' "${!COUNT[@]}" | sort); do
+    n="${COUNT[$dir]}"
+    (( n > WARN_THRESHOLD )) || continue
+    if [[ -n "${BASELINE[$dir]:-}" ]]; then
+        echo "BASELINE (tolerated): $dir has $n files (max $WARN_THRESHOLD)"
+        continue
+    fi
+    echo "WARNING: $dir has $n files (max $WARN_THRESHOLD) - group by concern"
+    warned=1
+    (( GATE == 1 )) && status=1
+done
+
+if (( warned == 0 )); then
+    echo "check-directory-size: OK - no un-baselined directory over $WARN_THRESHOLD flat files."
+fi
+exit $status