fix(cloud): create SQLite DO without deleting the old class in the same deploy (#1193)

The delete migration kept failing (code 10061): Cloudflare validates a class
delete against the LIVE binding, which still pointed at McpSessionDO, so binding
move + delete can't happen in one deploy. Drop the delete: v2 only creates the
new SQLite class McpSessionDOSqlite and the MCP_SESSION binding moves to it. The
old KV McpSessionDO is left orphaned (kept as a stub export so the migration
stays valid) and can be deleted in a later deploy now that nothing binds it.
Also repoint the generated MCP_SESSION binding type to McpSessionDOSqlite.

Author: RhysSullivan

apps/cloud/src/server.ts

@@ -1,3 +1,4 @@
+import { DurableObject } from "cloudflare:workers";
 import { SpanKind, SpanStatusCode, context, trace } from "@opentelemetry/api";
 import {
   ATTR_HTTP_REQUEST_METHOD,
@@ -46,6 +47,14 @@ export const McpSessionDOSqlite = Sentry.instrumentDurableObjectWithSentry(
   McpSessionDOBase,
 );
 
+// Orphaned placeholder for the original key-value `McpSessionDO` class (migration
+// v1). The live MCP session DO is now `McpSessionDOSqlite` (SQLite); the
+// `MCP_SESSION` binding moved to it. Cloudflare won't delete `McpSessionDO` in the
+// same deploy that moves its binding, so the class is left unbound and is kept
+// exported here only to satisfy the migration. It can be removed in a later deploy
+// (with a `deleted_classes: ["McpSessionDO"]` migration) now that nothing binds it.
+export class McpSessionDO extends DurableObject {}
+
 // ---------------------------------------------------------------------------
 // Worker fetch handler
 //

apps/cloud/worker-configuration.d.ts

@@ -14,7 +14,7 @@ declare namespace Cloudflare {
     WORKOS_COOKIE_PASSWORD: string;
     APP_URL: string;
     WORKOS_CLAIM_TOKEN: string;
-    MCP_SESSION: DurableObjectNamespace<import("./src/server").McpSessionDO>;
+    MCP_SESSION: DurableObjectNamespace<import("./src/server").McpSessionDOSqlite>;
     MARKETING: Fetcher /* executor-marketing */;
   }
 }

apps/cloud/wrangler.jsonc

@@ -25,20 +25,21 @@
     ],
   },
   // The MCP session DO moved to the Cloudflare Agents (`McpAgent`) base, which
-  // stores state in SQLite. The original `McpSessionDO` was created with the
-  // key-value backend (`new_classes`), and Cloudflare cannot convert a live class
-  // to SQLite in place, nor delete a class while a binding still references it.
-  // Session state is ephemeral, so v2 repoints the `MCP_SESSION` binding to a new
-  // SQLite-backed class (`McpSessionDOSqlite`) and deletes the old KV `McpSessionDO`
-  // (now unreferenced). The worker exports `McpSessionDOSqlite`, not `McpSessionDO`.
+  // stores state in SQLite. The original `McpSessionDO` was created on the
+  // key-value backend (`new_classes`) and cannot be converted in place. Cloudflare
+  // also refuses to delete a class in the same deploy that moves its binding (it
+  // validates the delete against the live binding), so v2 only CREATES the new
+  // SQLite class `McpSessionDOSqlite` and the `MCP_SESSION` binding moves to it.
+  // The old KV `McpSessionDO` is left orphaned (unbound, kept as a stub export in
+  // server.ts so the migration stays valid); it can be deleted in a later deploy
+  // now that nothing binds it. Session state is ephemeral, so nothing is lost.
   "migrations": [
     {
       "tag": "v1",
       "new_classes": ["McpSessionDO"],
     },
     {
       "tag": "v2",
-      "deleted_classes": ["McpSessionDO"],
       "new_sqlite_classes": ["McpSessionDOSqlite"],
     },
   ],