diff --git a/packages/cli/src/nonInteractiveCli.ts b/packages/cli/src/nonInteractiveCli.ts
index c237e56b..f2efe8fc 100644
--- a/packages/cli/src/nonInteractiveCli.ts
+++ b/packages/cli/src/nonInteractiveCli.ts
@@ -13,10 +13,10 @@ import {
   isTelemetrySdkInitialized,
   GeminiEventType,
   ToolErrorType,
+  parseAndFormatApiError,
 } from '@google/gemini-cli-core';
 import { Content, Part, FunctionCall } from '@google/genai';
 
-import { parseAndFormatApiError } from './ui/utils/errorParsing.js';
 import { ConsolePatcher } from './ui/utils/ConsolePatcher.js';
 
 export async function runNonInteractive(
diff --git a/packages/cli/src/ui/hooks/useGeminiStream.test.tsx b/packages/cli/src/ui/hooks/useGeminiStream.test.tsx
index 37d63e9a..9eed0912 100644
--- a/packages/cli/src/ui/hooks/useGeminiStream.test.tsx
+++ b/packages/cli/src/ui/hooks/useGeminiStream.test.tsx
@@ -51,6 +51,7 @@ const MockedGeminiClientClass = vi.hoisted(() =>
 const MockedUserPromptEvent = vi.hoisted(() =>
   vi.fn().mockImplementation(() => {}),
 );
+const mockParseAndFormatApiError = vi.hoisted(() => vi.fn());
 
 vi.mock('@google/gemini-cli-core', async (importOriginal) => {
   const actualCoreModule = (await importOriginal()) as any;
@@ -59,6 +60,7 @@ vi.mock('@google/gemini-cli-core', async (importOriginal) => {
     GitService: vi.fn(),
     GeminiClient: MockedGeminiClientClass,
     UserPromptEvent: MockedUserPromptEvent,
+    parseAndFormatApiError: mockParseAndFormatApiError,
   };
 });
 
@@ -127,11 +129,6 @@ vi.mock('./slashCommandProcessor.js', () => ({
   handleSlashCommand: vi.fn().mockReturnValue(false),
 }));
 
-const mockParseAndFormatApiError = vi.hoisted(() => vi.fn());
-vi.mock('../utils/errorParsing.js', () => ({
-  parseAndFormatApiError: mockParseAndFormatApiError,
-}));
-
 // --- END MOCKS ---
 
 describe('mergePartListUnions', () => {
diff --git a/packages/cli/src/ui/hooks/useGeminiStream.ts b/packages/cli/src/ui/hooks/useGeminiStream.ts
index 6f3cb4fd..99b727b6 100644
--- a/packages/cli/src/ui/hooks/useGeminiStream.ts
+++ b/packages/cli/src/ui/hooks/useGeminiStream.ts
@@ -25,6 +25,7 @@ import {
   UnauthorizedError,
   UserPromptEvent,
   DEFAULT_GEMINI_FLASH_MODEL,
+  parseAndFormatApiError,
 } from '@google/gemini-cli-core';
 import { type Part, type PartListUnion, FinishReason } from '@google/genai';
 import {
@@ -37,7 +38,6 @@ import {
   ToolCallStatus,
 } from '../types.js';
 import { isAtCommand } from '../utils/commandUtils.js';
-import { parseAndFormatApiError } from '../utils/errorParsing.js';
 import { useShellCommandProcessor } from './shellCommandProcessor.js';
 import { handleAtCommand } from './atCommandProcessor.js';
 import { findLastSafeSplitPoint } from '../utils/markdownUtilities.js';
diff --git a/packages/core/src/index.ts b/packages/core/src/index.ts
index 791446e3..a24cddbe 100644
--- a/packages/core/src/index.ts
+++ b/packages/core/src/index.ts
@@ -41,6 +41,7 @@ export * from './utils/systemEncoding.js';
 export * from './utils/textUtils.js';
 export * from './utils/formatters.js';
 export * from './utils/filesearch/fileSearch.js';
+export * from './utils/errorParsing.js';
 
 // Export services
 export * from './services/fileDiscoveryService.js';
diff --git a/packages/cli/src/ui/utils/errorParsing.test.ts b/packages/core/src/utils/errorParsing.test.ts
similarity index 98%
rename from packages/cli/src/ui/utils/errorParsing.test.ts
rename to packages/core/src/utils/errorParsing.test.ts
index 770dffad..f2a4709a 100644
--- a/packages/cli/src/ui/utils/errorParsing.test.ts
+++ b/packages/core/src/utils/errorParsing.test.ts
@@ -6,12 +6,11 @@
 
 import { describe, it, expect } from 'vitest';
 import { parseAndFormatApiError } from './errorParsing.js';
-import {
-  AuthType,
-  UserTierId,
-  DEFAULT_GEMINI_FLASH_MODEL,
-  isProQuotaExceededError,
-} from '@google/gemini-cli-core';
+import { isProQuotaExceededError } from './quotaErrorDetection.js';
+import { DEFAULT_GEMINI_FLASH_MODEL } from '../config/models.js';
+import { UserTierId } from '../code_assist/types.js';
+import { AuthType } from '../core/contentGenerator.js';
+import { StructuredError } from '../core/turn.js';
 
 describe('parseAndFormatApiError', () => {
   const _enterpriseMessage =
diff --git a/packages/cli/src/ui/utils/errorParsing.ts b/packages/core/src/utils/errorParsing.ts
similarity index 97%
rename from packages/cli/src/ui/utils/errorParsing.ts
rename to packages/core/src/utils/errorParsing.ts
index 5031bc0a..aa15a652 100644
--- a/packages/cli/src/ui/utils/errorParsing.ts
+++ b/packages/core/src/utils/errorParsing.ts
@@ -5,15 +5,17 @@
  */
 
 import {
-  AuthType,
-  UserTierId,
-  DEFAULT_GEMINI_FLASH_MODEL,
-  DEFAULT_GEMINI_MODEL,
   isProQuotaExceededError,
   isGenericQuotaExceededError,
   isApiError,
   isStructuredError,
-} from '@google/gemini-cli-core';
+} from './quotaErrorDetection.js';
+import {
+  DEFAULT_GEMINI_MODEL,
+  DEFAULT_GEMINI_FLASH_MODEL,
+} from '../config/models.js';
+import { UserTierId } from '../code_assist/types.js';
+import { AuthType } from '../core/contentGenerator.js';
 
 // Free Tier message functions
 const getRateLimitErrorMessageGoogleFree = (
diff --git a/packages/core/src/utils/quotaErrorDetection.ts b/packages/core/src/utils/quotaErrorDetection.ts
index 6fe9b312..1377b4fa 100644
--- a/packages/core/src/utils/quotaErrorDetection.ts
+++ b/packages/core/src/utils/quotaErrorDetection.ts
@@ -4,6 +4,8 @@
  * SPDX-License-Identifier: Apache-2.0
  */
 
+import { StructuredError } from '../core/turn.js';
+
 export interface ApiError {
   error: {
     code: number;
@@ -13,11 +15,6 @@ export interface ApiError {
   };
 }
 
-interface StructuredError {
-  message: string;
-  status?: number;
-}
-
 export function isApiError(error: unknown): error is ApiError {
   return (
     typeof error === 'object' &&