diff --git a/src/db/prisma/schema.prisma b/src/db/prisma/schema.prisma
index 17778b1..90ef49f 100644
--- a/src/db/prisma/schema.prisma
+++ b/src/db/prisma/schema.prisma
@@ -142,7 +142,12 @@ model SecretBackend {
 model Secret {
   id          String   @id @default(cuid())
   name        String   @unique
-  backendId   String                                  // FK to SecretBackend — dispatches read/write
+  // FK to SecretBackend. Default empty string lets `prisma db push` add the
+  // column to pre-existing rows without a data-loss reset; `bootstrapSecretBackends`
+  // then points any empty-string values at the seeded `default` plaintext backend
+  // on next mcpd startup. New rows written by SecretService always carry a
+  // valid FK immediately.
+  backendId   String   @default("")
   data        Json     @default("{}")                 // populated by plaintext backend only
   externalRef String   @default("")                   // populated by non-plaintext backends (e.g. "mount/path#v3")
   version     Int      @default(1)