diff --git a/api/app/clients/tools/util/handleTools.js b/api/app/clients/tools/util/handleTools.js
index adeb9f7ca99..d6244dfe0ab 100644
--- a/api/app/clients/tools/util/handleTools.js
+++ b/api/app/clients/tools/util/handleTools.js
@@ -451,10 +451,11 @@ const loadTools = async ({
   /** MCP server tools are initialized sequentially by server */
   let index = -1;
   const failedMCPServers = new Set();
-  const safeUser = createSafeUser(options.req?.user);
+  const safeUser = createSafeUser(options.req?.user, user);
   const requestScopedConnections =
     options.requestScopedConnections ?? getMCPRequestContext(options.req, options.res);
 
+
   for (const [serverName, toolConfigs] of Object.entries(requestedMCPTools)) {
     index++;
     /** @type {LCAvailableTools} */
diff --git a/api/app/clients/tools/util/handleTools.test.js b/api/app/clients/tools/util/handleTools.test.js
index 697649e3bde..9870650772f 100644
--- a/api/app/clients/tools/util/handleTools.test.js
+++ b/api/app/clients/tools/util/handleTools.test.js
@@ -451,4 +451,52 @@ describe('Tool Handlers', () => {
       );
     });
   });
+
+  describe('loadTools MCP user id propagation', () => {
+    // Regression guard: MCP tool-call requests shipped the literal "{{LIBRECHAT_USER_ID}}"
+    // placeholder in x-user-id headers because `loadTools` built the MCP `user` object from
+    // `options.req?.user` alone. When `req.user` is a plain object deserialized from the
+    // passport session (no `id` virtual, no `_id`), that object resolves to no usable id even
+    // though `loadTools` is already given the caller's resolved id via its own `user` param
+    // (see ToolService.js: `loadTools({ user: req.user.id, ... })`). Assert that id makes it
+    // into the object handed to `createMCPTools`.
+    const mcpServerName = 'test-mcp-server';
+    const mcpAllToolName = `${Constants.mcp_all}${Constants.mcp_delimiter}${mcpServerName}`;
+
+    beforeEach(() => {
+      mockGetServerConfig.mockResolvedValue({ startup: true });
+      mockCreateMCPTools.mockResolvedValue([]);
+    });
+
+    it('falls back to the loadTools `user` param when req.user has neither id nor _id', async () => {
+      const userId = fakeUser._id.toString();
+      const sessionUser = { email: 'fakeuser@example.com', provider: 'local' };
+
+      await loadTools({
+        user: userId,
+        tools: [mcpAllToolName],
+        options: { req: { user: sessionUser } },
+      });
+
+      expect(mockCreateMCPTools).toHaveBeenCalledWith(
+        expect.objectContaining({
+          user: expect.objectContaining({ id: userId }),
+        }),
+      );
+    });
+
+    it('prefers a resolvable req.user id over the loadTools `user` param', async () => {
+      await loadTools({
+        user: fakeUser._id.toString(),
+        tools: [mcpAllToolName],
+        options: { req: { user: { id: 'explicit-req-user-id' } } },
+      });
+
+      expect(mockCreateMCPTools).toHaveBeenCalledWith(
+        expect.objectContaining({
+          user: expect.objectContaining({ id: 'explicit-req-user-id' }),
+        }),
+      );
+    });
+  });
 });
diff --git a/api/server/controllers/agents/v1.spec.js b/api/server/controllers/agents/v1.spec.js
index fda2bdd6167..7f9000c48a7 100644
--- a/api/server/controllers/agents/v1.spec.js
+++ b/api/server/controllers/agents/v1.spec.js
@@ -1345,6 +1345,7 @@ describe('Agent Controllers - Mass Assignment Protection', () => {
           'author',
           'avatar',
           'category',
+          'conversation_starters',
           'description',
           'id',
           'is_promoted',
diff --git a/packages/api/src/mcp/__tests__/mcp.spec.ts b/packages/api/src/mcp/__tests__/mcp.spec.ts
index 539c04f6b94..ef6d2a1a497 100644
--- a/packages/api/src/mcp/__tests__/mcp.spec.ts
+++ b/packages/api/src/mcp/__tests__/mcp.spec.ts
@@ -586,7 +586,9 @@ describe('Environment Variable Extraction (MCP)', () => {
       const result1 = processMCPEnv({ options: obj1, user: userWithId });
       expect('headers' in result1 && result1.headers?.['User-Id']).toBe('user-123');
 
-      // Test with '_id' property only (should not work since we only check 'id')
+      // Test with '_id' property only. Our fork accepts _id as a fallback for id
+      // (PRs #29/#30/#31/#32 threaded this through createSafeUser and loadTools)
+      // because passport-deserialized session user objects only carry _id.
       const userWithUnderscore = createTestUser({
         id: undefined, // Remove default id to test _id
         _id: 'user-456',
@@ -601,8 +603,7 @@ describe('Environment Variable Extraction (MCP)', () => {
       };
 
       const result2 = processMCPEnv({ options: obj2, user: userWithUnderscore });
-      // Since we don't check _id, the placeholder should remain unchanged
-      expect('headers' in result2 && result2.headers?.['User-Id']).toBe('{{LIBRECHAT_USER_ID}}');
+      expect('headers' in result2 && result2.headers?.['User-Id']).toBe('user-456');
 
       // Test with both properties (id takes precedence)
       const userWithBoth = createTestUser({