diff --git a/apps/server/src/common/helpers/prosemirror/html/generateHTML.ts b/apps/server/src/common/helpers/prosemirror/html/generateHTML.ts
index 52196aa2..c55a8d88 100644
--- a/apps/server/src/common/helpers/prosemirror/html/generateHTML.ts
+++ b/apps/server/src/common/helpers/prosemirror/html/generateHTML.ts
@@ -16,11 +16,12 @@ import { getHTMLFromFragment } from './getHTMLFromFragment';
  * ```
  */
 export function generateHTML(doc: JSONContent, extensions: Extensions): string {
-  if (typeof window !== 'undefined') {
-    throw new Error(
-      'generateHTML can only be used in a Node environment\nIf you want to use this in a browser environment, use the `@tiptap/html` import instead.',
-    );
-  }
+  // No global-`window` guard here: this helper is server-only and self-contained
+  // (it serializes via `getHTMLFromFragment`, which creates its own happy-dom
+  // `Window` and never reads the global `window`). A guard on `typeof window`
+  // would be a false positive whenever a global `window` is injected into the
+  // Node process (e.g. by the in-process MCP module, which sets `global.window`
+  // via jsdom).
 
   const schema = getSchema(extensions);
   const contentNode = Node.fromJSON(schema, doc);
diff --git a/apps/server/src/common/helpers/prosemirror/html/generateJSON.ts b/apps/server/src/common/helpers/prosemirror/html/generateJSON.ts
index bd6e735c..771c87c0 100644
--- a/apps/server/src/common/helpers/prosemirror/html/generateJSON.ts
+++ b/apps/server/src/common/helpers/prosemirror/html/generateJSON.ts
@@ -21,11 +21,11 @@ export function generateJSON(
   extensions: Extensions,
   options?: ParseOptions,
 ): Record<string, any> {
-  if (typeof window !== 'undefined') {
-    throw new Error(
-      'generateJSON can only be used in a Node environment\nIf you want to use this in a browser environment, use the `@tiptap/html` import instead.',
-    );
-  }
+  // No global-`window` guard here: this helper is server-only and self-contained
+  // (it creates its own happy-dom `Window` below and never reads the global
+  // `window`). A guard on `typeof window` would be a false positive whenever a
+  // global `window` is injected into the Node process (e.g. by the in-process
+  // MCP module, which sets `global.window` via jsdom).
 
   const localWindow = new Window();
   const localDOMParser = new localWindow.DOMParser();
diff --git a/packages/mcp/src/client.ts b/packages/mcp/src/client.ts
index a2e60336..9873d119 100644
--- a/packages/mcp/src/client.ts
+++ b/packages/mcp/src/client.ts
@@ -732,7 +732,9 @@ export class DocmostClient {
     // Always fetch subpages to provide context to the agent
     let subpages: any[] = [];
     try {
-      subpages = await this.listSidebarPages(resultData.spaceId, pageId);
+      // `pageId` may be a slugId, but the sidebar-pages endpoint requires the
+      // UUID; `resultData.id` holds the resolved UUID returned by getPageRaw.
+      subpages = await this.listSidebarPages(resultData.spaceId, resultData.id);
     } catch (e: any) {
       console.warn("Failed to fetch subpages:", e);
     }