diff --git a/api/test/__mocks__/logger.js b/api/test/__mocks__/logger.js
index 62f9bee93a..94dd08bb1c 100644
--- a/api/test/__mocks__/logger.js
+++ b/api/test/__mocks__/logger.js
@@ -1,5 +1,13 @@
 jest.mock('winston', () => {
-  const mockFormatFunction = jest.fn((fn) => fn);
+  // Real `winston.format(fn)` returns a Format constructor whose instances
+  // expose a `.transform(info, opts)` method that winston's pipeline calls.
+  // The previous mock `(fn) => fn` collapsed this — `parsers.redactFormat()`
+  // (called at @librechat/data-schemas dist module-load) ended up invoking
+  // the inner transform fn with no `info` argument, throwing on `info.level`.
+  // Returning a thunk that yields `{ transform: fn }` matches real winston's
+  // shape just enough that module-load completes cleanly; the inner fn is
+  // only ever invoked by winston's pipeline (never at load time).
+  const mockFormatFunction = jest.fn((fn) => () => ({ transform: fn }));
 
   mockFormatFunction.colorize = jest.fn();
   mockFormatFunction.combine = jest.fn();
diff --git a/packages/api/src/agents/__tests__/initialize.test.ts b/packages/api/src/agents/__tests__/initialize.test.ts
index b98af340aa..6636c13af6 100644
--- a/packages/api/src/agents/__tests__/initialize.test.ts
+++ b/packages/api/src/agents/__tests__/initialize.test.ts
@@ -39,20 +39,34 @@ import type { ServerRequest, InitializeResultBase, EndpointTokenConfig } from '~
 import type { InitializeAgentDbMethods } from '../initialize';
 import { DEFAULT_MAX_CONTEXT_TOKENS } from '../initialize';
 
-// Mock logger
+// Mock logger — `format` must be a callable factory so @librechat/data-schemas
+// dist module-load completes cleanly; see api/test/__mocks__/logger.js.
 jest.mock('winston', () => ({
   createLogger: jest.fn(() => ({
     debug: jest.fn(),
     warn: jest.fn(),
     error: jest.fn(),
+    info: jest.fn(),
   })),
-  format: {
-    combine: jest.fn(),
-    colorize: jest.fn(),
-    simple: jest.fn(),
-  },
+  format: Object.assign(
+    jest.fn((fn) => () => ({ transform: fn })),
+    {
+      combine: jest.fn(),
+      colorize: jest.fn(),
+      simple: jest.fn(),
+      label: jest.fn(),
+      timestamp: jest.fn(),
+      printf: jest.fn(),
+      errors: jest.fn(),
+      splat: jest.fn(),
+      json: jest.fn(),
+    },
+  ),
+  addColors: jest.fn(),
   transports: {
     Console: jest.fn(),
+    DailyRotateFile: jest.fn(),
+    File: jest.fn(),
   },
 }));
 
diff --git a/packages/api/src/agents/__tests__/memory.test.ts b/packages/api/src/agents/__tests__/memory.test.ts
index dabe6de629..d23a07aa7d 100644
--- a/packages/api/src/agents/__tests__/memory.test.ts
+++ b/packages/api/src/agents/__tests__/memory.test.ts
@@ -5,19 +5,35 @@ import type { MemoryArtifact } from 'librechat-data-provider';
 import { createMemoryTool, processMemory } from '../memory';
 
 // Mock the logger
+// `winston.format` must be a callable factory (real winston returns a Format
+// constructor) so that `@librechat/data-schemas` dist code can complete its
+// module-load — see api/test/__mocks__/logger.js for the canonical shape.
 jest.mock('winston', () => ({
   createLogger: jest.fn(() => ({
     debug: jest.fn(),
     warn: jest.fn(),
     error: jest.fn(),
+    info: jest.fn(),
   })),
-  format: {
-    combine: jest.fn(),
-    colorize: jest.fn(),
-    simple: jest.fn(),
-  },
+  format: Object.assign(
+    jest.fn((fn) => () => ({ transform: fn })),
+    {
+      combine: jest.fn(),
+      colorize: jest.fn(),
+      simple: jest.fn(),
+      label: jest.fn(),
+      timestamp: jest.fn(),
+      printf: jest.fn(),
+      errors: jest.fn(),
+      splat: jest.fn(),
+      json: jest.fn(),
+    },
+  ),
+  addColors: jest.fn(),
   transports: {
     Console: jest.fn(),
+    DailyRotateFile: jest.fn(),
+    File: jest.fn(),
   },
 }));
 
diff --git a/packages/api/src/agents/__tests__/run-summarization.test.ts b/packages/api/src/agents/__tests__/run-summarization.test.ts
index 1aa8e0d58d..7d22511c21 100644
--- a/packages/api/src/agents/__tests__/run-summarization.test.ts
+++ b/packages/api/src/agents/__tests__/run-summarization.test.ts
@@ -9,7 +9,8 @@ import {
 } from 'librechat-data-provider';
 import { createRun } from '~/agents/run';
 
-// Mock winston logger
+// Mock winston logger — `format` must be callable so @librechat/data-schemas
+// dist module-load completes cleanly; see api/test/__mocks__/logger.js.
 jest.mock('winston', () => ({
   createLogger: jest.fn(() => ({
     debug: jest.fn(),
@@ -17,8 +18,26 @@ jest.mock('winston', () => ({
     error: jest.fn(),
     info: jest.fn(),
   })),
-  format: { combine: jest.fn(), colorize: jest.fn(), simple: jest.fn() },
-  transports: { Console: jest.fn() },
+  format: Object.assign(
+    jest.fn((fn) => () => ({ transform: fn })),
+    {
+      combine: jest.fn(),
+      colorize: jest.fn(),
+      simple: jest.fn(),
+      label: jest.fn(),
+      timestamp: jest.fn(),
+      printf: jest.fn(),
+      errors: jest.fn(),
+      splat: jest.fn(),
+      json: jest.fn(),
+    },
+  ),
+  addColors: jest.fn(),
+  transports: {
+    Console: jest.fn(),
+    DailyRotateFile: jest.fn(),
+    File: jest.fn(),
+  },
 }));
 
 // Mock env utilities so header resolution doesn't fail