diff --git a/src/blackboard/db.py b/src/blackboard/db.py
index a59ac73..ee0a27f 100644
--- a/src/blackboard/db.py
+++ b/src/blackboard/db.py
@@ -21,6 +21,31 @@ def init_db(db_path: Path) -> None:
         conn.close()
 
 
+def _migrate_v261(conn: sqlite3.Connection) -> None:
+    """v2.6.1 数据迁移：为旧 DB 添加新字段/新表（安全 ALTER）"""
+    # tasks 表新增字段
+    _safe_add_column(conn, "tasks", "current_agent", "TEXT")
+    _safe_add_column(conn, "tasks", "previous_agent", "TEXT")
+    _safe_add_column(conn, "tasks", "next_capability", "TEXT")
+    # routing_decisions 表（如果不存在，CREATE TABLE IF NOT EXISTS 已处理）
+    # idx_tasks_current_agent 索引
+    try:
+        conn.execute(
+            "CREATE INDEX IF NOT EXISTS idx_tasks_current_agent ON tasks(current_agent)")
+    except sqlite3.OperationalError:
+        pass
+
+
+def _safe_add_column(conn: sqlite3.Connection, table: str,
+                     column: str, col_type: str) -> None:
+    """安全添加列（已存在则跳过）"""
+    try:
+        conn.execute(f"ALTER TABLE {table} ADD COLUMN {column} {col_type}")
+    except sqlite3.OperationalError as e:
+        if "duplicate column" not in str(e).lower():
+            raise
+
+
 def get_connection(db_path: Path) -> sqlite3.Connection:
     """获取数据库连接（WAL + busy_timeout + foreign_keys）"""
     return _connect(db_path)