diff --git a/test-board.yaml b/test-board.yaml
new file mode 100644
index 0000000..a156ca0
--- /dev/null
+++ b/test-board.yaml
@@ -0,0 +1,22 @@
+version: 1
+project:
+  name: "substack-mcp"
+  test_command: "npm run type-check"
+  repo: "nanameru/substack-mcp"
+
+source_roots:
+  - worker
+  - src
+
+cases:
+  - id: TC-001
+    title: "Cloudflare Remote MCP本番デプロイ: OAuth保護されたMCPへ接続し読み取り専用で下書きを1件取得する"
+    feature: "Cloudflare Remote MCP本番デプロイ"
+    scenario: "OAuth保護されたMCPへ接続し読み取り専用で下書きを1件取得する"
+    status: passed
+    priority: high
+    type: e2e
+    source: [worker/index.ts, worker/oauth.ts, src/substack_mcp/cloud_api.py, wrangler.jsonc]
+    test_file: ""
+    issues: [6]
+    notes: "2026-09-12にChatGPTからOAuth接続し、11ツールの認識とlist_drafts(limit=1)の成功を確認。記事本文は表示せず、書き込み系ツールは未実行。"
diff --git a/worker/index.ts b/worker/index.ts
index 6471de1..c5d346c 100644
--- a/worker/index.ts
+++ b/worker/index.ts
@@ -211,13 +211,18 @@ function createServer() {
   return server;
 }
 
-const apiHandler = createMcpHandler(createServer);
+const handleMcpRequest = createMcpHandler(createServer);
+const apiHandler = {
+  fetch(request: Request, workerEnv: Env, ctx: ExecutionContext) {
+    return handleMcpRequest(request, workerEnv, ctx);
+  },
+} satisfies ExportedHandler<Env>;
 
 export default new OAuthProvider({
   authorizeEndpoint: "/authorize",
   tokenEndpoint: "/oauth/token",
   clientRegistrationEndpoint: "/oauth/register",
   apiRoute: "/mcp",
-  apiHandler: apiHandler as any,
+  apiHandler,
   defaultHandler: authHandler,
 });
diff --git a/worker/oauth.ts b/worker/oauth.ts
index ed3de0d..b136fc9 100644
--- a/worker/oauth.ts
+++ b/worker/oauth.ts
@@ -92,7 +92,7 @@ async function authorizeGet(request: Request, env: OAuthEnv): Promise<Response>
   return new Response(html, {
     headers: {
       "Content-Type": "text/html; charset=utf-8",
-      "Content-Security-Policy": "default-src 'none'; style-src 'unsafe-inline'; form-action 'self'; base-uri 'none'; frame-ancestors 'none'",
+      "Content-Security-Policy": "default-src 'none'; style-src 'unsafe-inline'; form-action 'self' https://github.com/login/oauth/authorize; base-uri 'none'; frame-ancestors 'none'",
       "Referrer-Policy": "no-referrer",
       "X-Frame-Options": "DENY",
       "Set-Cookie": secureCookie(CSRF_COOKIE, csrf, 600),
@@ -161,8 +161,22 @@ async function callback(request: Request, env: OAuthEnv): Promise<Response> {
     }),
   });
   if (!tokenResponse.ok) return jsonError("GitHub token exchange failed", 502);
-  const tokenData = (await tokenResponse.json()) as { access_token?: string };
-  if (!tokenData.access_token) return jsonError("GitHub did not return an access token", 502);
+  const tokenData = (await tokenResponse.json()) as {
+    access_token?: string;
+    error?: string;
+  };
+  if (!tokenData.access_token) {
+    // GitHub commonly returns HTTP 200 with a machine-readable OAuth error.
+    // Surface only that non-secret error code so credential/configuration issues
+    // can be distinguished without logging the authorization code or secrets.
+    const oauthError = tokenData.error?.replace(/[^a-z0-9_]/gi, "").slice(0, 80);
+    return jsonError(
+      oauthError
+        ? `GitHub token exchange failed: ${oauthError}`
+        : "GitHub did not return an access token",
+      502,
+    );
+  }
 
   const userResponse = await fetch("https://api.github.com/user", {
     headers: {
diff --git a/wrangler.jsonc b/wrangler.jsonc
index a0ce727..79537c1 100644
--- a/wrangler.jsonc
+++ b/wrangler.jsonc
@@ -32,7 +32,7 @@
   "kv_namespaces": [
     {
       "binding": "OAUTH_KV",
-      "id": "REPLACE_WITH_OAUTH_KV_ID"
+      "id": "2804e83ca60f4b6487b038442fed4779"
     }
   ]
 }