Fix MCP getPage tool returning page not found (#4166)

packages/gitbook/src/lib/pages.test.ts

@@ -35,6 +35,19 @@ describe('extractPagePath', () => {
     it('returns empty string for root URL', () => {
         expect(extractPagePath('https://docs.example.com/api/', baseURL)).toBe('');
     });
+
+    it('extracts path when base URL is at the root of the domain', () => {
+        expect(
+            extractPagePath(
+                'https://docs.example.com/merchant-account/user-management/sso',
+                'https://docs.example.com/'
+            )
+        ).toBe('merchant-account/user-management/sso');
+    });
+
+    it('returns empty string when URL equals root base URL', () => {
+        expect(extractPagePath('https://docs.example.com/', 'https://docs.example.com/')).toBe('');
+    });
 });
 
 describe('resolveFirstDocument', () => {

packages/gitbook/src/lib/pages.ts

@@ -413,11 +413,12 @@ export function extractPagePath(url: string, baseURL: string): string | undefine
     const urlPath = getURLPathname(url);
     const basePath = getURLPathname(baseURL);
 
-    if (!urlPath || !basePath) {
+    if (urlPath === undefined || basePath === undefined) {
         return undefined;
     }
 
-    if (urlPath.startsWith(`${basePath}/`) || urlPath === basePath) {
+    // When basePath is empty, the site is at the root of the domain, so any path matches
+    if (basePath === '' || urlPath.startsWith(`${basePath}/`) || urlPath === basePath) {
         return removeLeadingSlash(urlPath.slice(basePath.length));
     }
 }