From a03f1529adc103421be8a3597b85e5eca1764608 Mon Sep 17 00:00:00 2001
From: Claude Lin & Lay <eightborder@gmail.com>
Date: Thu, 23 Apr 2026 23:45:14 +0900
Subject: [PATCH] fix(mcp): retain RagMcpAgent as stub to satisfy migration
 history

Post-merge deploy of #109 failed with:
  New version of script does not export class 'RagMcpAgent' which is
  depended on by existing Durable Objects. [code: 10064]

The v1 migration still declares RagMcpAgent as an sqlite class, and Cloudflare
requires every declared class to exist in the script (or be removed via a
deleted_classes migration). Since the goal of the rename was to reach a fresh
DO namespace for RagMcpAgentV2, a renamed_classes migration would defeat that
by preserving state. Instead, keep RagMcpAgent as an empty DurableObject stub
that receives no traffic (no binding points to it).

Follow-up work: delete RagMcpAgent entirely via deleted_classes once the V2
switch is confirmed stable.

Closes #111
Refs #109
---
 src/index.ts |  3 +++
 src/mcp.ts   | 15 +++++++++++++++
 2 files changed, 18 insertions(+)

diff --git a/src/index.ts b/src/index.ts
index 394ca43..117bb0f 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -38,6 +38,9 @@ import { RagMcpAgentV2 } from "./mcp.js";
 // Durable Object: issue/PR state store (SQLite-backed)
 export { IssueStore } from "./store.js";
 
+// Durable Object: MCP server — legacy stub (retained for migration compatibility only).
+export { RagMcpAgent } from "./mcp.js";
+
 // Durable Object: MCP server (tools: search_issues, get_issue_context, list_recent_activity)
 export { RagMcpAgentV2 } from "./mcp.js";
 
diff --git a/src/mcp.ts b/src/mcp.ts
index 19ecd7b..7d382d0 100644
--- a/src/mcp.ts
+++ b/src/mcp.ts
@@ -12,6 +12,7 @@
  * idFromName("user-{githubUserId}").
  */
 
+import { DurableObject } from "cloudflare:workers";
 import { McpAgent } from "agents/mcp";
 import { McpServer } from "@modelcontextprotocol/sdk/server/mcp.js";
 import { z } from "zod";
@@ -65,6 +66,20 @@ function githubHeaders(token: string): Record<string, string> {
  */
 const INCLUDE_CONTENT_MAX_DOCS = 5;
 
+/**
+ * Legacy class retained solely to satisfy Cloudflare's "class must exist in
+ * script for classes declared in past migrations (v1 new_sqlite_classes)"
+ * constraint. MCP_OBJECT binding points to RagMcpAgentV2 now, so this class
+ * never receives live traffic. It exists only so `wrangler deploy` does not
+ * fail with "script does not export class 'RagMcpAgent'". A follow-up PR can
+ * delete this class together with a deleted_classes migration.
+ */
+export class RagMcpAgent extends DurableObject<Env> {
+  async fetch(): Promise<Response> {
+    return new Response("RagMcpAgent has been retired; use RagMcpAgentV2", { status: 410 });
+  }
+}
+
 export class RagMcpAgentV2 extends McpAgent<Env, unknown, McpProps> {
   // @ts-expect-error -- McpServer version mismatch between top-level SDK and agents' bundled copy (same issue as webhook-mcp; wrangler resolves at bundle time)
   server = new McpServer({