diff --git a/backend/mci-server/src/main/resources/db/migration/V15__add_range_partitions.sql b/backend/mci-server/src/main/resources/db/migration/V15__add_range_partitions.sql
index abf76b8..eff80a0 100644
--- a/backend/mci-server/src/main/resources/db/migration/V15__add_range_partitions.sql
+++ b/backend/mci-server/src/main/resources/db/migration/V15__add_range_partitions.sql
@@ -1,5 +1,11 @@
 -- Phase 1.5: 为高频表添加 MySQL RANGE 月分区（分区键 create_time）
 -- 架构设计文档：docs/architecture/2026-07-06-message-customer-interaction-design.md 第 2.6.2 节
+--
+-- 生产部署注意：
+-- 1. 本迁移对主键/唯一键和外键做了破坏性调整，上线前请先在预发布环境用真实数据量验证。
+-- 2. 大表（message_event / send_record）执行 DROP/ADD PRIMARY KEY 可能锁表，建议使用 pt-online-schema-change
+--    或预留低峰窗口；当前脚本为开发/MVP 阶段使用。
+-- 3. 未提供 down migration：取消分区需要重建表并恢复外键，操作复杂，请在上线前自行备份 schema。
 
 -- ============================
 -- 1. mci_message_event（消息事件表）
diff --git a/backend/mci-server/src/main/resources/db/migration/V16__add_conversation_tenant_time_index.sql b/backend/mci-server/src/main/resources/db/migration/V16__add_conversation_tenant_time_index.sql
new file mode 100644
index 0000000..9ecc74e
--- /dev/null
+++ b/backend/mci-server/src/main/resources/db/migration/V16__add_conversation_tenant_time_index.sql
@@ -0,0 +1,4 @@
+-- Phase 1.5 补充：为 mci_conversation 添加架构设计要求的 (tenant_code, create_time) 索引
+-- 注意：V15 中为了满足 MySQL 分区规则，唯一键已包含 create_time，导致唯一性约束弱化；
+-- 业务上应通过 event_id / task_id 等自然业务键保证唯一性。
+ALTER TABLE mci_conversation ADD KEY idx_tenant_time (tenant_code, create_time);
diff --git a/scripts/extend-mysql-partitions.sh b/scripts/extend-mysql-partitions.sh
index e711f9c..b9fe59f 100755
--- a/scripts/extend-mysql-partitions.sh
+++ b/scripts/extend-mysql-partitions.sh
@@ -17,6 +17,7 @@ MYSQL_USER="${MYSQL_USER:-root}"
 MYSQL_PASSWORD="${MYSQL_PASSWORD:-root}"
 MYSQL_DB="${MYSQL_DB:-sino_mci}"
 MONTHS_AHEAD="${MONTHS_AHEAD:-3}"
+DRY_RUN="${DRY_RUN:-0}"
 
 TABLES=(
     mci_message_event
@@ -24,12 +25,21 @@ TABLES=(
     mci_conversation
 )
 
+if ! command -v mysql >/dev/null 2>&1; then
+    echo "Error: mysql client not found in PATH" >&2
+    exit 1
+fi
+
 echo "Extending monthly partitions for database: ${MYSQL_DB}"
 echo "Host: ${MYSQL_HOST}:${MYSQL_PORT}, User: ${MYSQL_USER}, Months ahead: ${MONTHS_AHEAD}"
 
 for table in "${TABLES[@]}"; do
     echo "  -> ${table}"
-    mysql -h "${MYSQL_HOST}" -P "${MYSQL_PORT}" -u "${MYSQL_USER}" -p"${MYSQL_PASSWORD}" "${MYSQL_DB}" \
+    if [ "${DRY_RUN}" = "1" ]; then
+        echo "      CALL ExtendMonthlyPartitions('${table}', ${MONTHS_AHEAD});"
+        continue
+    fi
+    MYSQL_PWD="${MYSQL_PASSWORD}" mysql -h "${MYSQL_HOST}" -P "${MYSQL_PORT}" -u "${MYSQL_USER}" "${MYSQL_DB}" \
         -e "CALL ExtendMonthlyPartitions('${table}', ${MONTHS_AHEAD});"
 done