diff --git a/CURRENT_TASK.md b/CURRENT_TASK.md
index 64ac06c9..f0cec7cf 100644
--- a/CURRENT_TASK.md
+++ b/CURRENT_TASK.md
@@ -1619,3 +1619,166 @@ if (unlikely(tls->seg_base == 0)) {
 - C5 (256B) / C4 (128B) 対応 → coverage 拡大で相対 overhead 削減
 - Page metadata layout 最適化 → cache line alignment
 - Remote free 対応 → multi-thread workload 準備
+
+---
+
+## Phase v7-4: Policy Box 導入 (フロント芯の作り直し) ✅
+
+### 完成
+
+**実装箇所**:
+- `/mnt/workdisk/public_share/hakmem/core/box/smallobject_policy_v7_box.h`: Policy Box ヘッダー (新規作成)
+- `/mnt/workdisk/public_share/hakmem/core/smallobject_policy_v7.c`: Policy Box 実装 (新規作成)
+- `/mnt/workdisk/public_share/hakmem/core/front/malloc_tiny_fast.h`: v7 routing を Policy Box 経由に変更
+- `/mnt/workdisk/public_share/hakmem/Makefile`: `core/smallobject_policy_v7.o` を OBJS リストに追加
+
+**設計意図**:
+フロントを「size→class→route_kind→switch」の1層だけにして、ルート決定を Policy Box に集約。Box Theory の L3 に SmallPolicyV7 を配置し、ULTRA/v7/MID_v3/LEGACY の選択を一元化。
+
+### Policy Box 実装
+
+**1. Route Kind Enum (L0/L1/L1' layer selection)**:
+```c
+typedef enum {
+    SMALL_ROUTE_ULTRA,      // L0: C4-C7 ULTRA (FROZEN)
+    SMALL_ROUTE_V7,         // L1: SmallObject v7 (research box)
+    SMALL_ROUTE_MID_V3,     // L1': MID v3 (257-768B mid/small)
+    SMALL_ROUTE_LEGACY,     // L1': TinyHeap v1 / Pool v1 (fallback)
+} SmallRouteKind;
+```
+
+**2. Policy Snapshot Structure**:
+```c
+typedef struct SmallPolicyV7 {
+    SmallRouteKind route_kind[8];  // C0-C7 routing decision
+} SmallPolicyV7;
+```
+
+**3. Policy API**:
+```c
+/// Get policy snapshot (read-only, TLS cached)
+const SmallPolicyV7* small_policy_v7_snapshot(void);
+
+/// Initialize policy from ENV variables (called once at startup)
+/// Priority: ULTRA > v7 > MID_v3 > LEGACY
+void small_policy_v7_init_from_env(SmallPolicyV7* policy);
+
+/// Get route kind name for debugging
+const char* small_route_kind_name(SmallRouteKind kind);
+```
+
+### ENV 優先順位 (固定)
+
+**Priority 1: ULTRA (highest)**
+- `HAKMEM_TINY_C7_ULTRA_ENABLED` (default ON) → C7 ULTRA
+- `HAKMEM_TINY_C6_ULTRA_FREE_ENABLED` → C6 ULTRA (free-only, 将来拡張用)
+- Future: `HAKMEM_TINY_C4_ULTRA_ENABLED` / `C5_ULTRA_ENABLED`
+
+**Priority 2: SmallObject v7 (research box)**
+- `HAKMEM_SMALL_HEAP_V7_ENABLED` → v7 有効化
+- `HAKMEM_SMALL_HEAP_V7_CLASSES` (default 0x40 = C6) → v7 対象クラス
+
+**Priority 3: MID_v3 (mid/small range)**
+- `HAKMEM_MID_V3_ENABLED` → MID_v3 有効化
+- `HAKMEM_MID_V3_CLASSES` (default 0x60 = C5-C6) → MID_v3 対象クラス
+
+**Priority 4: LEGACY (fallback)**
+- Default for all classes not covered by above
+
+### フロント段階移行
+
+**alloc path** (malloc_tiny_fast.h, line 227-235):
+```c
+// Phase v7-4: Check Policy Box for v7 routing (before switch)
+const SmallPolicyV7* policy = small_policy_v7_snapshot();
+if (policy->route_kind[class_idx] == SMALL_ROUTE_V7) {
+    void* v7p = small_heap_alloc_fast_v7_stub(size, (uint8_t)class_idx);
+    if (TINY_HOT_LIKELY(v7p != NULL)) {
+        return v7p;
+    }
+    // v7 stub returned NULL -> fallback to legacy
+}
+```
+
+**free path** (malloc_tiny_fast.h, line 408-416):
+```c
+// Phase v7-4: Check Policy Box for v7 routing (before route lookup)
+const SmallPolicyV7* policy = small_policy_v7_snapshot();
+if (class_idx == 6 && policy->route_kind[class_idx] == SMALL_ROUTE_V7) {
+    if (small_heap_free_fast_v7_stub(ptr, (uint8_t)class_idx)) {
+        FREE_PATH_STAT_INC(smallheap_v7_fast);
+        return 1;
+    }
+    // v7 returned false (ptr not in v7 segment) -> fallback to legacy below
+}
+```
+
+### Box Theory 層構造
+
+**L0: ULTRA (frozen, C4-C7)**
+- C7 ULTRA: Phase ULTRA-1~6 (production)
+- C6/C5/C4 ULTRA: Phase ULTRA-7~9 (future)
+
+**L1: SmallObject v7 (research box)**
+- C6-only (Phase v7-1~4)
+- Future: C5/C4 expansion
+
+**L1': MID_v3 / LEGACY (fallback)**
+- MID_v3: 257-768B (C5-C6 range)
+- LEGACY: TinyHeap v1 / Pool v1
+
+**L2: Segment / RegionId**
+- SmallSegment_v7 (64MB mmap region)
+- RegionIdBox v6 (ptr → segment lookup)
+
+**L3: Policy / Stats / Learner**
+- **SmallPolicyV7** (this phase): Route decision
+- Stats: FreePathStatsBox / AllocGateStatsBox
+- Learner: (future) dynamic route selection
+
+### 段階移行戦略
+
+**Phase v7-4 現状**:
+- v7 関連のみ Policy box 経由に変更
+- ULTRA/MID_v3/LEGACY は既存の `tiny_route_env_box.h` を併用（後で統合予定）
+
+**将来の統一**:
+- `tiny_route_env_box.h` の ULTRA/MID_v3/LEGACY ルート判定を Policy box に統合
+- クラスごとの柔軟な優先順位設定
+- Learner 連携による動的ルート選択 (ENV override)
+
+### Debug Output
+
+初回 TLS 初期化時に stderr に出力:
+```
+[POLICY_V7_INIT] Route assignments:
+  C0: LEGACY
+  C1: LEGACY
+  C2: LEGACY
+  C3: LEGACY
+  C4: LEGACY
+  C5: LEGACY
+  C6: V7         (if HAKMEM_SMALL_HEAP_V7_ENABLED=1)
+  C7: ULTRA      (if HAKMEM_TINY_C7_ULTRA_ENABLED=1, default ON)
+```
+
+### ビルド確認
+
+**コンパイル**: 成功
+```
+gcc -O3 ... -c -o core/smallobject_policy_v7.o core/smallobject_policy_v7.c
+gcc -o bench_tiny_hot_hakmem ... core/smallobject_policy_v7.o ... -lm -lpthread -flto
+```
+
+**リンク**: 成功 (all object lists updated)
+- `OBJS_BASE`
+- `BENCH_HAKMEM_OBJS_BASE`
+- `TINY_BENCH_OBJS_BASE`
+
+### 次の拡張
+
+**Phase v7-5 候補**:
+1. **ULTRA/MID_v3/LEGACY 統合**: `tiny_route_env_box.h` → Policy box に移行
+2. **Learner 連携**: ENV defaults + runtime learning override
+3. **クラスごとの柔軟な優先順位**: ENV で ULTRA vs v7 の順序を逆転可能に
+4. **Multi-class v7**: C5/C4 追加 → coverage 拡大
diff --git a/Makefile b/Makefile
index 5291ac38..c26eccd1 100644
--- a/Makefile
+++ b/Makefile
@@ -218,7 +218,7 @@ LDFLAGS += $(EXTRA_LDFLAGS)
 
 # Targets
 TARGET = test_hakmem
-OBJS_BASE = hakmem.o hakmem_config.o hakmem_tiny_config.o hakmem_ucb1.o hakmem_bigcache.o hakmem_pool.o hakmem_l25_pool.o hakmem_site_rules.o hakmem_tiny.o core/box/ss_allocation_box.o superslab_stats.o superslab_cache.o superslab_ace.o superslab_slab.o superslab_backend.o core/superslab_head_stub.o hakmem_smallmid.o tiny_sticky.o tiny_remote.o tiny_publish.o tiny_debug_ring.o hakmem_tiny_magazine.o hakmem_tiny_stats.o hakmem_tiny_sfc.o hakmem_tiny_query.o hakmem_tiny_rss.o hakmem_tiny_registry.o hakmem_tiny_remote_target.o hakmem_tiny_bg_spill.o tiny_adaptive_sizing.o hakmem_super_registry.o hakmem_shared_pool.o hakmem_shared_pool_acquire.o hakmem_shared_pool_release.o hakmem_elo.o hakmem_batch.o hakmem_p2.o hakmem_sizeclass_dist.o hakmem_evo.o hakmem_debug.o hakmem_sys.o hakmem_whale.o hakmem_policy.o hakmem_ace.o hakmem_ace_stats.o hakmem_prof.o hakmem_learner.o hakmem_size_hist.o hakmem_learn_log.o hakmem_syscall.o hakmem_ace_metrics.o hakmem_ace_ucb1.o hakmem_ace_controller.o tiny_fastcache.o core/box/superslab_expansion_box.o core/box/integrity_box.o core/box/free_publish_box.o core/box/mailbox_box.o core/box/front_gate_box.o core/box/front_gate_classifier.o core/box/capacity_box.o core/box/carve_push_box.o core/box/prewarm_box.o core/box/ss_hot_prewarm_box.o core/box/front_metrics_box.o core/box/bench_fast_box.o core/box/ss_addr_map_box.o core/box/slab_recycling_box.o core/box/pagefault_telemetry_box.o core/box/tiny_sizeclass_hist_box.o core/box/tiny_env_box.o core/box/tiny_route_box.o core/box/free_front_v3_env_box.o core/box/free_path_stats_box.o core/box/free_dispatch_stats_box.o core/box/alloc_gate_stats_box.o core/box/tiny_c6_ultra_free_box.o core/box/tiny_c5_ultra_free_box.o core/box/tiny_c4_ultra_free_box.o core/box/tiny_page_box.o core/box/tiny_class_policy_box.o core/box/tiny_class_stats_box.o core/box/tiny_policy_learner_box.o core/box/ss_budget_box.o core/box/tiny_mem_stats_box.o core/box/c7_meta_used_counter_box.o core/box/wrapper_env_box.o core/box/madvise_guard_box.o core/box/libm_reloc_guard_box.o core/box/ptr_trace_box.o core/box/link_missing_stubs.o core/box/super_reg_box.o core/box/shared_pool_box.o core/box/remote_side_box.o core/page_arena.o core/front/tiny_unified_cache.o core/tiny_alloc_fast_push.o core/tiny_c7_ultra_segment.o core/tiny_c7_ultra.o core/link_stubs.o core/tiny_failfast.o core/tiny_destructors.o core/smallobject_hotbox_v3.o core/smallobject_hotbox_v4.o core/smallobject_hotbox_v5.o core/smallsegment_v5.o core/smallobject_cold_iface_v5.o core/smallsegment_v6.o core/smallobject_cold_iface_v6.o core/smallobject_core_v6.o core/region_id_v6.o core/smallsegment_v7.o core/smallobject_cold_iface_v7.o core/mid_hotbox_v3.o
+OBJS_BASE = hakmem.o hakmem_config.o hakmem_tiny_config.o hakmem_ucb1.o hakmem_bigcache.o hakmem_pool.o hakmem_l25_pool.o hakmem_site_rules.o hakmem_tiny.o core/box/ss_allocation_box.o superslab_stats.o superslab_cache.o superslab_ace.o superslab_slab.o superslab_backend.o core/superslab_head_stub.o hakmem_smallmid.o tiny_sticky.o tiny_remote.o tiny_publish.o tiny_debug_ring.o hakmem_tiny_magazine.o hakmem_tiny_stats.o hakmem_tiny_sfc.o hakmem_tiny_query.o hakmem_tiny_rss.o hakmem_tiny_registry.o hakmem_tiny_remote_target.o hakmem_tiny_bg_spill.o tiny_adaptive_sizing.o hakmem_super_registry.o hakmem_shared_pool.o hakmem_shared_pool_acquire.o hakmem_shared_pool_release.o hakmem_elo.o hakmem_batch.o hakmem_p2.o hakmem_sizeclass_dist.o hakmem_evo.o hakmem_debug.o hakmem_sys.o hakmem_whale.o hakmem_policy.o hakmem_ace.o hakmem_ace_stats.o hakmem_prof.o hakmem_learner.o hakmem_size_hist.o hakmem_learn_log.o hakmem_syscall.o hakmem_ace_metrics.o hakmem_ace_ucb1.o hakmem_ace_controller.o tiny_fastcache.o core/box/superslab_expansion_box.o core/box/integrity_box.o core/box/free_publish_box.o core/box/mailbox_box.o core/box/front_gate_box.o core/box/front_gate_classifier.o core/box/capacity_box.o core/box/carve_push_box.o core/box/prewarm_box.o core/box/ss_hot_prewarm_box.o core/box/front_metrics_box.o core/box/bench_fast_box.o core/box/ss_addr_map_box.o core/box/slab_recycling_box.o core/box/pagefault_telemetry_box.o core/box/tiny_sizeclass_hist_box.o core/box/tiny_env_box.o core/box/tiny_route_box.o core/box/free_front_v3_env_box.o core/box/free_path_stats_box.o core/box/free_dispatch_stats_box.o core/box/alloc_gate_stats_box.o core/box/tiny_c6_ultra_free_box.o core/box/tiny_c5_ultra_free_box.o core/box/tiny_c4_ultra_free_box.o core/box/tiny_page_box.o core/box/tiny_class_policy_box.o core/box/tiny_class_stats_box.o core/box/tiny_policy_learner_box.o core/box/ss_budget_box.o core/box/tiny_mem_stats_box.o core/box/c7_meta_used_counter_box.o core/box/wrapper_env_box.o core/box/madvise_guard_box.o core/box/libm_reloc_guard_box.o core/box/ptr_trace_box.o core/box/link_missing_stubs.o core/box/super_reg_box.o core/box/shared_pool_box.o core/box/remote_side_box.o core/page_arena.o core/front/tiny_unified_cache.o core/tiny_alloc_fast_push.o core/tiny_c7_ultra_segment.o core/tiny_c7_ultra.o core/link_stubs.o core/tiny_failfast.o core/tiny_destructors.o core/smallobject_hotbox_v3.o core/smallobject_hotbox_v4.o core/smallobject_hotbox_v5.o core/smallsegment_v5.o core/smallobject_cold_iface_v5.o core/smallsegment_v6.o core/smallobject_cold_iface_v6.o core/smallobject_core_v6.o core/region_id_v6.o core/smallsegment_v7.o core/smallobject_cold_iface_v7.o core/mid_hotbox_v3.o core/smallobject_policy_v7.o
 OBJS = $(OBJS_BASE)
 
 # Shared library
@@ -250,7 +250,7 @@ endif
 # Benchmark targets
 BENCH_HAKMEM = bench_allocators_hakmem
 BENCH_SYSTEM = bench_allocators_system
-BENCH_HAKMEM_OBJS_BASE = hakmem.o hakmem_config.o hakmem_tiny_config.o hakmem_ucb1.o hakmem_bigcache.o hakmem_pool.o hakmem_l25_pool.o hakmem_site_rules.o hakmem_tiny.o core/box/ss_allocation_box.o superslab_stats.o superslab_cache.o superslab_ace.o superslab_slab.o superslab_backend.o core/superslab_head_stub.o hakmem_smallmid.o tiny_sticky.o tiny_remote.o tiny_publish.o tiny_debug_ring.o hakmem_tiny_magazine.o hakmem_tiny_stats.o hakmem_tiny_sfc.o hakmem_tiny_query.o hakmem_tiny_rss.o hakmem_tiny_registry.o hakmem_tiny_remote_target.o hakmem_tiny_bg_spill.o tiny_adaptive_sizing.o hakmem_super_registry.o hakmem_shared_pool.o hakmem_shared_pool_acquire.o hakmem_shared_pool_release.o hakmem_elo.o hakmem_batch.o hakmem_p2.o hakmem_sizeclass_dist.o hakmem_evo.o hakmem_debug.o hakmem_sys.o hakmem_whale.o hakmem_policy.o hakmem_ace.o hakmem_ace_stats.o hakmem_prof.o hakmem_learner.o hakmem_size_hist.o hakmem_learn_log.o hakmem_syscall.o hakmem_ace_metrics.o hakmem_ace_ucb1.o hakmem_ace_controller.o tiny_fastcache.o core/box/superslab_expansion_box.o core/box/integrity_box.o core/box/free_publish_box.o core/box/mailbox_box.o core/box/front_gate_box.o core/box/front_gate_classifier.o core/box/capacity_box.o core/box/carve_push_box.o core/box/prewarm_box.o core/box/ss_hot_prewarm_box.o core/box/front_metrics_box.o core/box/bench_fast_box.o core/box/ss_addr_map_box.o core/box/slab_recycling_box.o core/box/pagefault_telemetry_box.o core/box/tiny_sizeclass_hist_box.o core/box/tiny_env_box.o core/box/tiny_route_box.o core/box/free_front_v3_env_box.o core/box/free_path_stats_box.o core/box/free_dispatch_stats_box.o core/box/alloc_gate_stats_box.o core/box/tiny_c6_ultra_free_box.o core/box/tiny_c5_ultra_free_box.o core/box/tiny_c4_ultra_free_box.o core/box/tiny_page_box.o core/box/tiny_class_policy_box.o core/box/tiny_class_stats_box.o core/box/tiny_policy_learner_box.o core/box/ss_budget_box.o core/box/tiny_mem_stats_box.o core/box/c7_meta_used_counter_box.o core/box/wrapper_env_box.o core/box/madvise_guard_box.o core/box/libm_reloc_guard_box.o core/box/ptr_trace_box.o core/box/link_missing_stubs.o core/box/super_reg_box.o core/box/shared_pool_box.o core/box/remote_side_box.o core/page_arena.o core/front/tiny_unified_cache.o core/tiny_alloc_fast_push.o core/tiny_c7_ultra_segment.o core/tiny_c7_ultra.o core/link_stubs.o core/tiny_failfast.o core/tiny_destructors.o core/smallobject_hotbox_v3.o core/smallobject_hotbox_v4.o core/smallobject_hotbox_v5.o core/smallsegment_v5.o core/smallobject_cold_iface_v5.o core/smallsegment_v6.o core/smallobject_cold_iface_v6.o core/smallobject_core_v6.o core/region_id_v6.o core/smallsegment_v7.o core/smallobject_cold_iface_v7.o core/mid_hotbox_v3.o bench_allocators_hakmem.o
+BENCH_HAKMEM_OBJS_BASE = hakmem.o hakmem_config.o hakmem_tiny_config.o hakmem_ucb1.o hakmem_bigcache.o hakmem_pool.o hakmem_l25_pool.o hakmem_site_rules.o hakmem_tiny.o core/box/ss_allocation_box.o superslab_stats.o superslab_cache.o superslab_ace.o superslab_slab.o superslab_backend.o core/superslab_head_stub.o hakmem_smallmid.o tiny_sticky.o tiny_remote.o tiny_publish.o tiny_debug_ring.o hakmem_tiny_magazine.o hakmem_tiny_stats.o hakmem_tiny_sfc.o hakmem_tiny_query.o hakmem_tiny_rss.o hakmem_tiny_registry.o hakmem_tiny_remote_target.o hakmem_tiny_bg_spill.o tiny_adaptive_sizing.o hakmem_super_registry.o hakmem_shared_pool.o hakmem_shared_pool_acquire.o hakmem_shared_pool_release.o hakmem_elo.o hakmem_batch.o hakmem_p2.o hakmem_sizeclass_dist.o hakmem_evo.o hakmem_debug.o hakmem_sys.o hakmem_whale.o hakmem_policy.o hakmem_ace.o hakmem_ace_stats.o hakmem_prof.o hakmem_learner.o hakmem_size_hist.o hakmem_learn_log.o hakmem_syscall.o hakmem_ace_metrics.o hakmem_ace_ucb1.o hakmem_ace_controller.o tiny_fastcache.o core/box/superslab_expansion_box.o core/box/integrity_box.o core/box/free_publish_box.o core/box/mailbox_box.o core/box/front_gate_box.o core/box/front_gate_classifier.o core/box/capacity_box.o core/box/carve_push_box.o core/box/prewarm_box.o core/box/ss_hot_prewarm_box.o core/box/front_metrics_box.o core/box/bench_fast_box.o core/box/ss_addr_map_box.o core/box/slab_recycling_box.o core/box/pagefault_telemetry_box.o core/box/tiny_sizeclass_hist_box.o core/box/tiny_env_box.o core/box/tiny_route_box.o core/box/free_front_v3_env_box.o core/box/free_path_stats_box.o core/box/free_dispatch_stats_box.o core/box/alloc_gate_stats_box.o core/box/tiny_c6_ultra_free_box.o core/box/tiny_c5_ultra_free_box.o core/box/tiny_c4_ultra_free_box.o core/box/tiny_page_box.o core/box/tiny_class_policy_box.o core/box/tiny_class_stats_box.o core/box/tiny_policy_learner_box.o core/box/ss_budget_box.o core/box/tiny_mem_stats_box.o core/box/c7_meta_used_counter_box.o core/box/wrapper_env_box.o core/box/madvise_guard_box.o core/box/libm_reloc_guard_box.o core/box/ptr_trace_box.o core/box/link_missing_stubs.o core/box/super_reg_box.o core/box/shared_pool_box.o core/box/remote_side_box.o core/page_arena.o core/front/tiny_unified_cache.o core/tiny_alloc_fast_push.o core/tiny_c7_ultra_segment.o core/tiny_c7_ultra.o core/link_stubs.o core/tiny_failfast.o core/tiny_destructors.o core/smallobject_hotbox_v3.o core/smallobject_hotbox_v4.o core/smallobject_hotbox_v5.o core/smallsegment_v5.o core/smallobject_cold_iface_v5.o core/smallsegment_v6.o core/smallobject_cold_iface_v6.o core/smallobject_core_v6.o core/region_id_v6.o core/smallsegment_v7.o core/smallobject_cold_iface_v7.o core/mid_hotbox_v3.o core/smallobject_policy_v7.o bench_allocators_hakmem.o
 BENCH_HAKMEM_OBJS = $(BENCH_HAKMEM_OBJS_BASE)
 ifeq ($(POOL_TLS_PHASE1),1)
 BENCH_HAKMEM_OBJS += pool_tls.o pool_refill.o pool_tls_arena.o pool_tls_registry.o pool_tls_remote.o
@@ -427,7 +427,7 @@ test-box-refactor: box-refactor
 	./larson_hakmem 10 8 128 1024 1 12345 4
 
 # Phase 4: Tiny Pool benchmarks (properly linked with hakmem)
-TINY_BENCH_OBJS_BASE = hakmem.o hakmem_config.o hakmem_tiny_config.o hakmem_ucb1.o hakmem_bigcache.o hakmem_pool.o hakmem_l25_pool.o hakmem_site_rules.o hakmem_tiny.o core/box/ss_allocation_box.o superslab_stats.o superslab_cache.o superslab_ace.o superslab_slab.o superslab_backend.o core/superslab_head_stub.o hakmem_smallmid.o core/box/superslab_expansion_box.o core/box/integrity_box.o core/box/mailbox_box.o core/box/front_gate_box.o core/box/front_gate_classifier.o core/box/free_publish_box.o core/box/capacity_box.o core/box/carve_push_box.o core/box/prewarm_box.o core/box/ss_hot_prewarm_box.o core/box/front_metrics_box.o core/box/bench_fast_box.o core/box/ss_addr_map_box.o core/box/slab_recycling_box.o core/box/pagefault_telemetry_box.o core/box/tiny_sizeclass_hist_box.o core/box/tiny_env_box.o core/box/tiny_route_box.o core/box/free_front_v3_env_box.o core/box/free_path_stats_box.o core/box/free_dispatch_stats_box.o core/box/alloc_gate_stats_box.o core/box/tiny_c6_ultra_free_box.o core/box/tiny_c5_ultra_free_box.o core/box/tiny_c4_ultra_free_box.o core/box/tiny_page_box.o core/box/tiny_class_policy_box.o core/box/tiny_class_stats_box.o core/box/tiny_policy_learner_box.o core/box/ss_budget_box.o core/box/tiny_mem_stats_box.o core/box/c7_meta_used_counter_box.o core/box/wrapper_env_box.o core/box/madvise_guard_box.o core/box/libm_reloc_guard_box.o core/box/ptr_trace_box.o core/box/link_missing_stubs.o core/box/super_reg_box.o core/box/shared_pool_box.o core/box/remote_side_box.o core/page_arena.o core/front/tiny_unified_cache.o tiny_sticky.o tiny_remote.o tiny_publish.o tiny_debug_ring.o hakmem_tiny_magazine.o hakmem_tiny_stats.o hakmem_tiny_sfc.o hakmem_tiny_query.o hakmem_tiny_rss.o hakmem_tiny_registry.o hakmem_tiny_remote_target.o hakmem_tiny_bg_spill.o tiny_adaptive_sizing.o hakmem_super_registry.o hakmem_shared_pool.o hakmem_shared_pool_acquire.o hakmem_shared_pool_release.o hakmem_elo.o hakmem_batch.o hakmem_p2.o hakmem_sizeclass_dist.o hakmem_evo.o hakmem_debug.o hakmem_sys.o hakmem_whale.o hakmem_policy.o hakmem_ace.o hakmem_ace_stats.o hakmem_prof.o hakmem_learner.o hakmem_size_hist.o hakmem_learn_log.o hakmem_syscall.o hakmem_ace_metrics.o hakmem_ace_ucb1.o hakmem_ace_controller.o tiny_fastcache.o core/tiny_alloc_fast_push.o core/tiny_c7_ultra_segment.o core/tiny_c7_ultra.o core/link_stubs.o core/tiny_failfast.o core/tiny_destructors.o core/smallobject_hotbox_v3.o core/smallobject_hotbox_v4.o core/smallobject_hotbox_v5.o core/smallsegment_v5.o core/smallobject_cold_iface_v5.o core/smallsegment_v6.o core/smallobject_cold_iface_v6.o core/smallobject_core_v6.o core/region_id_v6.o core/smallsegment_v7.o core/smallobject_cold_iface_v7.o core/mid_hotbox_v3.o
+TINY_BENCH_OBJS_BASE = hakmem.o hakmem_config.o hakmem_tiny_config.o hakmem_ucb1.o hakmem_bigcache.o hakmem_pool.o hakmem_l25_pool.o hakmem_site_rules.o hakmem_tiny.o core/box/ss_allocation_box.o superslab_stats.o superslab_cache.o superslab_ace.o superslab_slab.o superslab_backend.o core/superslab_head_stub.o hakmem_smallmid.o core/box/superslab_expansion_box.o core/box/integrity_box.o core/box/mailbox_box.o core/box/front_gate_box.o core/box/front_gate_classifier.o core/box/free_publish_box.o core/box/capacity_box.o core/box/carve_push_box.o core/box/prewarm_box.o core/box/ss_hot_prewarm_box.o core/box/front_metrics_box.o core/box/bench_fast_box.o core/box/ss_addr_map_box.o core/box/slab_recycling_box.o core/box/pagefault_telemetry_box.o core/box/tiny_sizeclass_hist_box.o core/box/tiny_env_box.o core/box/tiny_route_box.o core/box/free_front_v3_env_box.o core/box/free_path_stats_box.o core/box/free_dispatch_stats_box.o core/box/alloc_gate_stats_box.o core/box/tiny_c6_ultra_free_box.o core/box/tiny_c5_ultra_free_box.o core/box/tiny_c4_ultra_free_box.o core/box/tiny_page_box.o core/box/tiny_class_policy_box.o core/box/tiny_class_stats_box.o core/box/tiny_policy_learner_box.o core/box/ss_budget_box.o core/box/tiny_mem_stats_box.o core/box/c7_meta_used_counter_box.o core/box/wrapper_env_box.o core/box/madvise_guard_box.o core/box/libm_reloc_guard_box.o core/box/ptr_trace_box.o core/box/link_missing_stubs.o core/box/super_reg_box.o core/box/shared_pool_box.o core/box/remote_side_box.o core/page_arena.o core/front/tiny_unified_cache.o tiny_sticky.o tiny_remote.o tiny_publish.o tiny_debug_ring.o hakmem_tiny_magazine.o hakmem_tiny_stats.o hakmem_tiny_sfc.o hakmem_tiny_query.o hakmem_tiny_rss.o hakmem_tiny_registry.o hakmem_tiny_remote_target.o hakmem_tiny_bg_spill.o tiny_adaptive_sizing.o hakmem_super_registry.o hakmem_shared_pool.o hakmem_shared_pool_acquire.o hakmem_shared_pool_release.o hakmem_elo.o hakmem_batch.o hakmem_p2.o hakmem_sizeclass_dist.o hakmem_evo.o hakmem_debug.o hakmem_sys.o hakmem_whale.o hakmem_policy.o hakmem_ace.o hakmem_ace_stats.o hakmem_prof.o hakmem_learner.o hakmem_size_hist.o hakmem_learn_log.o hakmem_syscall.o hakmem_ace_metrics.o hakmem_ace_ucb1.o hakmem_ace_controller.o tiny_fastcache.o core/tiny_alloc_fast_push.o core/tiny_c7_ultra_segment.o core/tiny_c7_ultra.o core/link_stubs.o core/tiny_failfast.o core/tiny_destructors.o core/smallobject_hotbox_v3.o core/smallobject_hotbox_v4.o core/smallobject_hotbox_v5.o core/smallsegment_v5.o core/smallobject_cold_iface_v5.o core/smallsegment_v6.o core/smallobject_cold_iface_v6.o core/smallobject_core_v6.o core/region_id_v6.o core/smallsegment_v7.o core/smallobject_cold_iface_v7.o core/mid_hotbox_v3.o core/smallobject_policy_v7.o
 TINY_BENCH_OBJS = $(TINY_BENCH_OBJS_BASE)
 ifeq ($(POOL_TLS_PHASE1),1)
 TINY_BENCH_OBJS += pool_tls.o pool_refill.o core/pool_tls_arena.o pool_tls_registry.o pool_tls_remote.o
diff --git a/core/box/smallobject_policy_v7_box.h b/core/box/smallobject_policy_v7_box.h
new file mode 100644
index 00000000..c07ef645
--- /dev/null
+++ b/core/box/smallobject_policy_v7_box.h
@@ -0,0 +1,49 @@
+// smallobject_policy_v7_box.h - SmallObject Policy v7 (Phase v7-4)
+//
+// Purpose:
+//   - Centralized routing policy for ULTRA / v7 / MID_v3 / LEGACY
+//   - Single source of truth for class → route_kind mapping
+//   - ENV configuration managed in one place (L3 Policy layer)
+
+#ifndef HAKMEM_SMALLOBJECT_POLICY_V7_BOX_H
+#define HAKMEM_SMALLOBJECT_POLICY_V7_BOX_H
+
+#include <stdint.h>
+#include <stdbool.h>
+
+// ============================================================================
+// Route Kind Enum (L0/L1/L1' layer selection)
+// ============================================================================
+
+typedef enum {
+    SMALL_ROUTE_ULTRA,      // L0: C4-C7 ULTRA (FROZEN)
+    SMALL_ROUTE_V7,         // L1: SmallObject v7 (research box)
+    SMALL_ROUTE_MID_V3,     // L1': MID v3 (257-768B mid/small)
+    SMALL_ROUTE_LEGACY,     // L1': TinyHeap v1 / Pool v1 (fallback)
+} SmallRouteKind;
+
+// ============================================================================
+// Policy Snapshot Structure
+// ============================================================================
+
+typedef struct SmallPolicyV7 {
+    SmallRouteKind route_kind[8];  // C0-C7 routing decision
+} SmallPolicyV7;
+
+// ============================================================================
+// Policy API
+// ============================================================================
+
+/// Get policy snapshot (read-only, TLS cached)
+/// Frontend calls this to determine route_kind[class_idx]
+const SmallPolicyV7* small_policy_v7_snapshot(void);
+
+/// Initialize policy from ENV variables (called once at startup)
+/// Priority: ULTRA > v7 > MID_v3 > LEGACY
+/// @param policy: Policy structure to initialize
+void small_policy_v7_init_from_env(SmallPolicyV7* policy);
+
+/// Get route kind name for debugging
+const char* small_route_kind_name(SmallRouteKind kind);
+
+#endif // HAKMEM_SMALLOBJECT_POLICY_V7_BOX_H
diff --git a/core/front/malloc_tiny_fast.h b/core/front/malloc_tiny_fast.h
index 239c1aea..facfdddb 100644
--- a/core/front/malloc_tiny_fast.h
+++ b/core/front/malloc_tiny_fast.h
@@ -46,6 +46,7 @@
 #include "../box/smallobject_core_v6_box.h" // SmallObject Core v6 (Phase V6-HDR-2)
 #include "../box/smallobject_v6_env_box.h"  // SmallObject v6 ENV control (Phase V6-HDR-2)
 #include "../box/smallobject_hotbox_v7_box.h" // SmallObject HotBox v7 stub (Phase v7-1)
+#include "../box/smallobject_policy_v7_box.h" // Phase v7-4: Policy Box
 #include "../box/tiny_c7_ultra_box.h" // C7 ULTRA stub (UF-1, delegates to v3)
 #include "../box/tiny_c6_ultra_free_box.h" // Phase 4-2: C6 ULTRA-free (free-only, C6-only)
 #include "../box/tiny_c5_ultra_free_box.h" // Phase 5-1/5-2: C5 ULTRA-free + alloc integration
@@ -223,9 +224,19 @@ static inline void* malloc_tiny_fast(size_t size) {
         }
     }
 
+    // Phase v7-4: Check Policy Box for v7 routing (before switch)
+    const SmallPolicyV7* policy = small_policy_v7_snapshot();
+    if (policy->route_kind[class_idx] == SMALL_ROUTE_V7) {
+        void* v7p = small_heap_alloc_fast_v7_stub(size, (uint8_t)class_idx);
+        if (TINY_HOT_LIKELY(v7p != NULL)) {
+            return v7p;
+        }
+        // v7 stub returned NULL -> fallback to legacy
+    }
+
     switch (route) {
         case TINY_ROUTE_SMALL_HEAP_V7: {
-            // Phase v7-1: C6-only v7 stub (MID v3 fallback)
+            // Phase v7-4: v7 routing now handled by Policy Box above (kept for legacy compatibility)
             void* v7p = small_heap_alloc_fast_v7_stub(size, (uint8_t)class_idx);
             if (TINY_HOT_LIKELY(v7p != NULL)) {
                 return v7p;
@@ -394,10 +405,20 @@ static inline int free_tiny_fast(void* ptr) {
         return 1;
     }
 
+    // Phase v7-4: Check Policy Box for v7 routing (before route lookup)
+    const SmallPolicyV7* policy = small_policy_v7_snapshot();
+    if (class_idx == 6 && policy->route_kind[class_idx] == SMALL_ROUTE_V7) {
+        if (small_heap_free_fast_v7_stub(ptr, (uint8_t)class_idx)) {
+            FREE_PATH_STAT_INC(smallheap_v7_fast);
+            return 1;
+        }
+        // v7 returned false (ptr not in v7 segment) -> fallback to legacy below
+    }
+
     tiny_route_kind_t route = tiny_route_for_class((uint8_t)class_idx);
 
-    // Phase v7-2: v7 early-exit for C6 (v7 uses separate mmap segment, not SuperSlab)
-    // Must check BEFORE ss_fast_lookup since v7 pointers won't be in SuperSlab registry
+    // Phase v7-2: v7 early-exit for C6 (legacy path, now handled by Policy Box above)
+    // Kept for compatibility with old routing system
     if (class_idx == 6 && route == TINY_ROUTE_SMALL_HEAP_V7) {
         if (small_heap_free_fast_v7_stub(ptr, (uint8_t)class_idx)) {
             FREE_PATH_STAT_INC(smallheap_v7_fast);
diff --git a/core/smallobject_policy_v7.c b/core/smallobject_policy_v7.c
new file mode 100644
index 00000000..1181bc26
--- /dev/null
+++ b/core/smallobject_policy_v7.c
@@ -0,0 +1,118 @@
+// smallobject_policy_v7.c - Policy Box implementation
+
+#include <stdlib.h>
+#include <string.h>
+#include <stdio.h>
+#include "box/smallobject_policy_v7_box.h"
+
+#ifndef likely
+#define likely(x)   __builtin_expect(!!(x), 1)
+#define unlikely(x) __builtin_expect(!!(x), 0)
+#endif
+
+// ============================================================================
+// TLS Policy Snapshot
+// ============================================================================
+
+static __thread SmallPolicyV7 g_small_policy_v7;
+static __thread int g_small_policy_v7_init = 0;
+
+const SmallPolicyV7* small_policy_v7_snapshot(void) {
+    if (unlikely(!g_small_policy_v7_init)) {
+        small_policy_v7_init_from_env(&g_small_policy_v7);
+        g_small_policy_v7_init = 1;
+    }
+    return &g_small_policy_v7;
+}
+
+// ============================================================================
+// ENV Helpers
+// ============================================================================
+
+static inline bool env_enabled(const char* name) {
+    const char* e = getenv(name);
+    return (e && *e && *e != '0');
+}
+
+static inline uint32_t env_class_mask(const char* name, uint32_t default_mask) {
+    const char* e = getenv(name);
+    if (e && *e) {
+        return (uint32_t)strtoul(e, NULL, 0);
+    }
+    return default_mask;
+}
+
+// ============================================================================
+// Policy Initialization from ENV
+// ============================================================================
+
+void small_policy_v7_init_from_env(SmallPolicyV7* policy) {
+    if (!policy) return;
+
+    // Default: all classes go to LEGACY
+    for (int i = 0; i < 8; i++) {
+        policy->route_kind[i] = SMALL_ROUTE_LEGACY;
+    }
+
+    // Priority 3: MID_v3 (257-768B, C5-C6 range)
+    // ENV: HAKMEM_MID_V3_ENABLED, HAKMEM_MID_V3_CLASSES
+    if (env_enabled("HAKMEM_MID_V3_ENABLED")) {
+        uint32_t mid_mask = env_class_mask("HAKMEM_MID_V3_CLASSES", 0x60); // C5-C6 default
+        for (int i = 0; i < 8; i++) {
+            if (mid_mask & (1u << i)) {
+                policy->route_kind[i] = SMALL_ROUTE_MID_V3;
+            }
+        }
+    }
+
+    // Priority 2: SmallObject v7 (research box, C6-only for now)
+    // ENV: HAKMEM_SMALL_HEAP_V7_ENABLED, HAKMEM_SMALL_HEAP_V7_CLASSES
+    if (env_enabled("HAKMEM_SMALL_HEAP_V7_ENABLED")) {
+        uint32_t v7_mask = env_class_mask("HAKMEM_SMALL_HEAP_V7_CLASSES", 0x40); // C6 default
+        for (int i = 0; i < 8; i++) {
+            if (v7_mask & (1u << i)) {
+                policy->route_kind[i] = SMALL_ROUTE_V7;
+            }
+        }
+    }
+
+    // Priority 1: ULTRA (highest priority, C4-C7)
+    // ENV: HAKMEM_TINY_C7_ULTRA_ENABLED (C7), HAKMEM_TINY_C6_ULTRA_FREE_ENABLED (C6), etc.
+    // Note: For now, we check individual ULTRA ENV vars
+
+    // C7 ULTRA (default ON)
+    if (env_enabled("HAKMEM_TINY_C7_ULTRA_ENABLED")) {
+        policy->route_kind[7] = SMALL_ROUTE_ULTRA;
+    }
+
+    // C6 ULTRA (if C6 ULTRA free is enabled, route to ULTRA)
+    // Note: This is a free-only optimization, not full ULTRA for C6 yet
+    // Keep C6 routing as-is (v7 or MID_v3) for now
+
+    // C4-C5 ULTRA (if enabled via ENV)
+    // TODO: Add HAKMEM_TINY_C4_ULTRA_ENABLED / C5 when implemented
+
+    // Debug output (if needed)
+    static int g_debug_once = 0;
+    if (!g_debug_once) {
+        g_debug_once = 1;
+        fprintf(stderr, "[POLICY_V7_INIT] Route assignments:\n");
+        for (int i = 0; i < 8; i++) {
+            fprintf(stderr, "  C%d: %s\n", i, small_route_kind_name(policy->route_kind[i]));
+        }
+    }
+}
+
+// ============================================================================
+// Utility
+// ============================================================================
+
+const char* small_route_kind_name(SmallRouteKind kind) {
+    switch (kind) {
+        case SMALL_ROUTE_ULTRA:   return "ULTRA";
+        case SMALL_ROUTE_V7:      return "V7";
+        case SMALL_ROUTE_MID_V3:  return "MID_V3";
+        case SMALL_ROUTE_LEGACY:  return "LEGACY";
+        default:                  return "UNKNOWN";
+    }
+}
diff --git a/docs/analysis/SMALLOBJECT_V7_DESIGN.md b/docs/analysis/SMALLOBJECT_V7_DESIGN.md
index 9db1cc6a..de8cd1ba 100644
--- a/docs/analysis/SMALLOBJECT_V7_DESIGN.md
+++ b/docs/analysis/SMALLOBJECT_V7_DESIGN.md
@@ -340,3 +340,51 @@ RegionIdBox / SegmentBox_v7 / PageStatsBox
 
 ---
 
+## 7. Phase v7-4: Policy Box (L3 層の明確化)
+
+### Policy Box の役割
+
+SmallPolicyV7 Box を L3 に配置し、「どのクラスをどの層に送るか」を一元管理：
+
+```c
+typedef struct SmallPolicyV7 {
+    SmallRouteKind route_kind[8];  // C0-C7
+} SmallPolicyV7;
+
+const SmallPolicyV7* small_policy_v7_snapshot(void);
+```
+
+### フロントの責務
+
+フロントは Policy Snapshot を読んで route を選ぶだけ：
+
+```c
+const SmallPolicyV7* policy = small_policy_v7_snapshot();
+SmallRouteKind route = policy->route_kind[class_idx];
+
+switch (route) {
+    case SMALL_ROUTE_ULTRA:   // L0
+    case SMALL_ROUTE_V7:      // L1
+    case SMALL_ROUTE_MID_V3:  // L1'
+    case SMALL_ROUTE_LEGACY:  // L1'
+}
+```
+
+### ENV の一元化
+
+ENV 変数は Policy init で一度だけ読む：
+- `HAKMEM_TINY_C7_ULTRA_ENABLED`
+- `HAKMEM_SMALL_HEAP_V7_ENABLED` + `HAKMEM_SMALL_HEAP_V7_CLASSES`
+- `HAKMEM_MID_V3_ENABLED` + `HAKMEM_MID_V3_CLASSES`
+
+優先順位: ULTRA > v7 > MID_v3 > LEGACY (固定)
+
+将来的にはクラスごとの柔軟な優先順位設定や、Learner 連携による動的ルート選択も可能。
+
+### 段階移行
+
+Phase v7-4 では v7 関連のみ Policy box 経由に変更。
+ULTRA/MID_v3/LEGACY は既存の `tiny_route_env_box.h` を併用（後で統合予定）。
+
+---
+
diff --git a/hakmem.d b/hakmem.d
index af412cff..e1851e0d 100644
--- a/hakmem.d
+++ b/hakmem.d
@@ -116,6 +116,7 @@ hakmem.o: core/hakmem.c core/hakmem.h core/hakmem_build_flags.h \
  core/box/../front/../box/smallsegment_v7_box.h \
  core/box/../front/../box/smallobject_cold_iface_v7_box.h \
  core/box/../front/../box/region_id_v6_box.h \
+ core/box/../front/../box/smallobject_policy_v7_box.h \
  core/box/../front/../box/tiny_c7_ultra_box.h \
  core/box/../front/../box/tiny_c7_ultra_segment_box.h \
  core/box/../front/../box/tiny_c6_ultra_free_box.h \
@@ -329,6 +330,7 @@ core/box/../front/../box/smallobject_hotbox_v7_box.h:
 core/box/../front/../box/smallsegment_v7_box.h:
 core/box/../front/../box/smallobject_cold_iface_v7_box.h:
 core/box/../front/../box/region_id_v6_box.h:
+core/box/../front/../box/smallobject_policy_v7_box.h:
 core/box/../front/../box/tiny_c7_ultra_box.h:
 core/box/../front/../box/tiny_c7_ultra_segment_box.h:
 core/box/../front/../box/tiny_c6_ultra_free_box.h: