diff --git a/modules/postgres/client.ts b/modules/postgres/client.ts
index 7582494..fa60b1b 100644
--- a/modules/postgres/client.ts
+++ b/modules/postgres/client.ts
@@ -39,7 +39,16 @@ export class PostgresClient {
   static fromEnv(env: NodeJS.ProcessEnv = process.env): PostgresClient {
     const url = env.MESH_PROVISION_POSTGRES ? safeUrl(env.MESH_PROVISION_POSTGRES) : undefined;
     const host = env.MESH_POSTGRES_HOST ?? url?.hostname;
-    const port = Number(env.MESH_POSTGRES_PORT ?? url?.port ?? "5432") || 5432;
+    // MESH_PROVISION_POSTGRES_PORT is the seat's twin (mesh-controller's own
+    // internal/envfile.Placed pattern): which port this machine actually put mesh-store at, when
+    // that differs from what the connection string above already says — e.g. adopted in place at
+    // a predecessor's port. Empty means the mesh has nothing to add and the string's own port
+    // stands; a placeholder the mesh never filled (a manifest ahead of the running controller)
+    // is treated the same way, not as a fault.
+    const seatPort = (env.MESH_PROVISION_POSTGRES_PORT ?? "").trim();
+    const filledSeatPort = seatPort && !/^\$\{[^}]*\}$/.test(seatPort) ? seatPort : undefined;
+    const portSource = env.MESH_POSTGRES_PORT ?? filledSeatPort ?? url?.port ?? "5432";
+    const port = Number(portSource) || 5432;
     const user = env.MESH_POSTGRES_USER ?? url?.username ?? "postgres";
     const password = env.MESH_POSTGRES_PASSWORD ?? readSecretFile(env.MESH_PROVISION_PASSWORD_FILE);
     if (!host || !password) {
diff --git a/modules/postgres/module.json b/modules/postgres/module.json
index fcc2c2c..2b65929 100644
--- a/modules/postgres/module.json
+++ b/modules/postgres/module.json
@@ -97,7 +97,8 @@
         "/var/lib/postgres/superuser.secret:/run/secrets/superuser:ro"
       ],
       "env": {
-        "MESH_PROVISION_POSTGRES": "postgres://postgres@127.0.0.1:${seat:mesh-store:5432}/postgres?sslmode=disable",
+        "MESH_PROVISION_POSTGRES": "postgres://postgres@127.0.0.1:5432/postgres?sslmode=disable",
+        "MESH_PROVISION_POSTGRES_PORT": "${seat:mesh-store:5432}",
         "MESH_PROVISION_PASSWORD_FILE": "/run/secrets/superuser",
         "MESH_BROKER_FILE": "/run/secrets/broker",
         "MESH_RECEIVES": "/var/lib/postgres/grants/mesh.json"