diff --git a/alembic/versions/20260806_client_related_person_scope_columns.py b/alembic/versions/20260806_client_related_person_scope_columns.py
new file mode 100644
index 0000000..34035c1
--- /dev/null
+++ b/alembic/versions/20260806_client_related_person_scope_columns.py
@@ -0,0 +1,108 @@
+"""Add Business Unit and Client Branch scope to client related persons.
+
+This migration is intentionally defensive. It adds only columns, foreign keys,
+and indexes that are missing, so it is safe for databases where part of the
+change may already exist.
+"""
+
+from alembic import op
+import sqlalchemy as sa
+
+
+revision = "20260806_related_person_scope"
+down_revision = "20260805_scope_aware_services"
+branch_labels = None
+depends_on = None
+
+
+TABLE_NAME = "client_related_persons"
+
+
+def _column_names(inspector) -> set[str]:
+    return {column["name"] for column in inspector.get_columns(TABLE_NAME)}
+
+
+def _index_names(inspector) -> set[str]:
+    return {index["name"] for index in inspector.get_indexes(TABLE_NAME) if index.get("name")}
+
+
+def _foreign_key_names(inspector) -> set[str]:
+    return {
+        foreign_key["name"]
+        for foreign_key in inspector.get_foreign_keys(TABLE_NAME)
+        if foreign_key.get("name")
+    }
+
+
+def upgrade():
+    bind = op.get_bind()
+    inspector = sa.inspect(bind)
+
+    columns = _column_names(inspector)
+
+    with op.batch_alter_table(TABLE_NAME) as batch:
+        if "business_unit_id" not in columns:
+            batch.add_column(sa.Column("business_unit_id", sa.Integer(), nullable=True))
+        if "client_branch_id" not in columns:
+            batch.add_column(sa.Column("client_branch_id", sa.Integer(), nullable=True))
+
+    inspector = sa.inspect(bind)
+    foreign_keys = _foreign_key_names(inspector)
+    indexes = _index_names(inspector)
+
+    with op.batch_alter_table(TABLE_NAME) as batch:
+        if "fk_client_related_persons_business_unit" not in foreign_keys:
+            batch.create_foreign_key(
+                "fk_client_related_persons_business_unit",
+                "client_business_units",
+                ["business_unit_id"],
+                ["id"],
+                ondelete="SET NULL",
+            )
+        if "fk_client_related_persons_client_branch" not in foreign_keys:
+            batch.create_foreign_key(
+                "fk_client_related_persons_client_branch",
+                "client_branches",
+                ["client_branch_id"],
+                ["id"],
+                ondelete="SET NULL",
+            )
+        if "ix_client_related_persons_business_unit_id" not in indexes:
+            batch.create_index(
+                "ix_client_related_persons_business_unit_id",
+                ["business_unit_id"],
+            )
+        if "ix_client_related_persons_client_branch_id" not in indexes:
+            batch.create_index(
+                "ix_client_related_persons_client_branch_id",
+                ["client_branch_id"],
+            )
+
+
+def downgrade():
+    bind = op.get_bind()
+    inspector = sa.inspect(bind)
+
+    columns = _column_names(inspector)
+    indexes = _index_names(inspector)
+    foreign_keys = _foreign_key_names(inspector)
+
+    with op.batch_alter_table(TABLE_NAME) as batch:
+        if "ix_client_related_persons_client_branch_id" in indexes:
+            batch.drop_index("ix_client_related_persons_client_branch_id")
+        if "ix_client_related_persons_business_unit_id" in indexes:
+            batch.drop_index("ix_client_related_persons_business_unit_id")
+        if "fk_client_related_persons_client_branch" in foreign_keys:
+            batch.drop_constraint(
+                "fk_client_related_persons_client_branch",
+                type_="foreignkey",
+            )
+        if "fk_client_related_persons_business_unit" in foreign_keys:
+            batch.drop_constraint(
+                "fk_client_related_persons_business_unit",
+                type_="foreignkey",
+            )
+        if "client_branch_id" in columns:
+            batch.drop_column("client_branch_id")
+        if "business_unit_id" in columns:
+            batch.drop_column("business_unit_id")