Add error messaging for 429 errors (#1316)

5 files changed, 110 insertions, 33 deletions

diff --git a/packages/cli/src/nonInteractiveCli.test.ts b/packages/cli/src/nonInteractiveCli.test.ts
index 959cf03f..2bee1f24 100644
--- a/packages/cli/src/nonInteractiveCli.test.ts
+++ b/packages/cli/src/nonInteractiveCli.test.ts
@@ -215,8 +215,7 @@ describe('runNonInteractive', () => {
     await runNonInteractive(mockConfig, 'Initial fail');
 
     expect(consoleErrorSpy).toHaveBeenCalledWith(
-      'Error processing input:',
-      apiError,
+      '[API Error: API connection failed]',
     );
   });
 });
diff --git a/packages/cli/src/nonInteractiveCli.ts b/packages/cli/src/nonInteractiveCli.ts
index 01ec62c8..02bbfd52 100644
--- a/packages/cli/src/nonInteractiveCli.ts
+++ b/packages/cli/src/nonInteractiveCli.ts
@@ -19,6 +19,8 @@ import {
   GenerateContentResponse,
 } from '@google/genai';
 
+import { parseAndFormatApiError } from './ui/utils/errorParsing.js';
+
 function getResponseText(response: GenerateContentResponse): string | null {
   if (response.candidates && response.candidates.length > 0) {
     const candidate = response.candidates[0];
@@ -126,7 +128,7 @@ export async function runNonInteractive(
       }
     }
   } catch (error) {
-    console.error('Error processing input:', error);
+    console.error(parseAndFormatApiError(error));
     process.exit(1);
   } finally {
     if (isTelemetrySdkInitialized()) {
diff --git a/packages/cli/src/ui/hooks/useGeminiStream.ts b/packages/cli/src/ui/hooks/useGeminiStream.ts
index 921fbdb1..e045fdeb 100644
--- a/packages/cli/src/ui/hooks/useGeminiStream.ts
+++ b/packages/cli/src/ui/hooks/useGeminiStream.ts
@@ -396,7 +396,10 @@ export const useGeminiStream = (
         setPendingHistoryItem(null);
       }
       addItem(
-        { type: MessageType.ERROR, text: `[API Error: ${eventValue.message}]` },
+        {
+          type: MessageType.ERROR,
+          text: parseAndFormatApiError(eventValue.error),
+        },
         userMessageTimestamp,
       );
     },
@@ -530,6 +533,10 @@ export const useGeminiStream = (
           setPendingHistoryItem(null);
         }
       } catch (error: unknown) {
+        console.log(
+          'GEMINI_DEBUG: Caught error in useGeminiStream.ts:',
+          JSON.stringify(error),
+        );
         if (isAuthError(error)) {
           onAuthError();
         } else if (!isNodeError(error) || error.name !== 'AbortError') {
diff --git a/packages/cli/src/ui/utils/errorParsing.test.ts b/packages/cli/src/ui/utils/errorParsing.test.ts
index afee5793..0dbd75c8 100644
--- a/packages/cli/src/ui/utils/errorParsing.test.ts
+++ b/packages/cli/src/ui/utils/errorParsing.test.ts
@@ -6,29 +6,46 @@
 
 import { describe, it, expect } from 'vitest';
 import { parseAndFormatApiError } from './errorParsing.js';
+import { StructuredError } from '@gemini-cli/core';
 
 describe('parseAndFormatApiError', () => {
+  const rateLimitMessage =
+    'Please wait and try again later. To increase your limits, upgrade to a plan with higher limits, or use /auth to switch to using a paid API key from AI Studio at https://aistudio.google.com/apikey';
+
   it('should format a valid API error JSON', () => {
     const errorMessage =
       'got status: 400 Bad Request. {"error":{"code":400,"message":"API key not valid. Please pass a valid API key.","status":"INVALID_ARGUMENT"}}';
     const expected =
-      'API Error: API key not valid. Please pass a valid API key. (Status: INVALID_ARGUMENT)';
+      '[API Error: API key not valid. Please pass a valid API key. (Status: INVALID_ARGUMENT)]';
+    expect(parseAndFormatApiError(errorMessage)).toBe(expected);
+  });
+
+  it('should format a 429 API error JSON with the custom message', () => {
+    const errorMessage =
+      'got status: 429 Too Many Requests. {"error":{"code":429,"message":"Rate limit exceeded","status":"RESOURCE_EXHAUSTED"}}';
+    const expected = `[API Error: Rate limit exceeded (Status: RESOURCE_EXHAUSTED)]\n${rateLimitMessage}`;
     expect(parseAndFormatApiError(errorMessage)).toBe(expected);
   });
 
   it('should return the original message if it is not a JSON error', () => {
     const errorMessage = 'This is a plain old error message';
-    expect(parseAndFormatApiError(errorMessage)).toBe(errorMessage);
+    expect(parseAndFormatApiError(errorMessage)).toBe(
+      `[API Error: ${errorMessage}]`,
+    );
   });
 
   it('should return the original message for malformed JSON', () => {
     const errorMessage = '[Stream Error: {"error": "malformed}';
-    expect(parseAndFormatApiError(errorMessage)).toBe(errorMessage);
+    expect(parseAndFormatApiError(errorMessage)).toBe(
+      `[API Error: ${errorMessage}]`,
+    );
   });
 
   it('should handle JSON that does not match the ApiError structure', () => {
     const errorMessage = '[Stream Error: {"not_an_error": "some other json"}]';
-    expect(parseAndFormatApiError(errorMessage)).toBe(errorMessage);
+    expect(parseAndFormatApiError(errorMessage)).toBe(
+      `[API Error: ${errorMessage}]`,
+    );
   });
 
   it('should format a nested API error', () => {
@@ -49,8 +66,32 @@ describe('parseAndFormatApiError', () => {
       },
     });
 
-    expect(parseAndFormatApiError(errorMessage)).toBe(
-      "API Error: Gemini 2.5 Pro Preview doesn't have a free quota tier. For more information on this error, head to: https://ai.google.dev/gemini-api/docs/rate-limits. (Status: Too Many Requests)",
-    );
+    const expected = `[API Error: Gemini 2.5 Pro Preview doesn't have a free quota tier. For more information on this error, head to: https://ai.google.dev/gemini-api/docs/rate-limits. (Status: Too Many Requests)]\n${rateLimitMessage}`;
+
+    expect(parseAndFormatApiError(errorMessage)).toBe(expected);
+  });
+
+  it('should format a StructuredError', () => {
+    const error: StructuredError = {
+      message: 'A structured error occurred',
+      status: 500,
+    };
+    const expected = '[API Error: A structured error occurred]';
+    expect(parseAndFormatApiError(error)).toBe(expected);
+  });
+
+  it('should format a 429 StructuredError with the custom message', () => {
+    const error: StructuredError = {
+      message: 'Rate limit exceeded',
+      status: 429,
+    };
+    const expected = `[API Error: Rate limit exceeded]\n${rateLimitMessage}`;
+    expect(parseAndFormatApiError(error)).toBe(expected);
+  });
+
+  it('should handle an unknown error type', () => {
+    const error = 12345;
+    const expected = '[API Error: An unknown error occurred.]';
+    expect(parseAndFormatApiError(error)).toBe(expected);
   });
 });
diff --git a/packages/cli/src/ui/utils/errorParsing.ts b/packages/cli/src/ui/utils/errorParsing.ts
index aec337b6..1aca15ae 100644
--- a/packages/cli/src/ui/utils/errorParsing.ts
+++ b/packages/cli/src/ui/utils/errorParsing.ts
@@ -4,6 +4,11 @@
  * SPDX-License-Identifier: Apache-2.0
  */
 
+import { StructuredError } from '@gemini-cli/core';
+
+const RATE_LIMIT_ERROR_MESSAGE =
+  '\nPlease wait and try again later. To increase your limits, upgrade to a plan with higher limits, or use /auth to switch to using a paid API key from AI Studio at https://aistudio.google.com/apikey';
+
 export interface ApiError {
   error: {
     code: number;
@@ -23,34 +28,57 @@ function isApiError(error: unknown): error is ApiError {
   );
 }
 
-export function parseAndFormatApiError(errorMessage: string): string {
-  // The error message might be prefixed with some text, like "[Stream Error: ...]".
-  // We want to find the start of the JSON object.
-  const jsonStart = errorMessage.indexOf('{');
-  if (jsonStart === -1) {
-    return errorMessage; // Not a JSON error, return as is.
+function isStructuredError(error: unknown): error is StructuredError {
+  return (
+    typeof error === 'object' &&
+    error !== null &&
+    'message' in error &&
+    typeof (error as StructuredError).message === 'string'
+  );
+}
+
+export function parseAndFormatApiError(error: unknown): string {
+  if (isStructuredError(error)) {
+    let text = `[API Error: ${error.message}]`;
+    if (error.status === 429) {
+      text += RATE_LIMIT_ERROR_MESSAGE;
+    }
+    return text;
   }
 
-  const jsonString = errorMessage.substring(jsonStart);
+  // The error message might be a string containing a JSON object.
+  if (typeof error === 'string') {
+    const jsonStart = error.indexOf('{');
+    if (jsonStart === -1) {
+      return `[API Error: ${error}]`; // Not a JSON error, return as is.
+    }
+
+    const jsonString = error.substring(jsonStart);
 
-  try {
-    const error = JSON.parse(jsonString) as unknown;
-    if (isApiError(error)) {
-      let finalMessage = error.error.message;
-      try {
-        // See if the message is a stringified JSON with another error
-        const nestedError = JSON.parse(finalMessage) as unknown;
-        if (isApiError(nestedError)) {
-          finalMessage = nestedError.error.message;
+    try {
+      const parsedError = JSON.parse(jsonString) as unknown;
+      if (isApiError(parsedError)) {
+        let finalMessage = parsedError.error.message;
+        try {
+          // See if the message is a stringified JSON with another error
+          const nestedError = JSON.parse(finalMessage) as unknown;
+          if (isApiError(nestedError)) {
+            finalMessage = nestedError.error.message;
+          }
+        } catch (_e) {
+          // It's not a nested JSON error, so we just use the message as is.
+        }
+        let text = `[API Error: ${finalMessage} (Status: ${parsedError.error.status})]`;
+        if (parsedError.error.code === 429) {
+          text += RATE_LIMIT_ERROR_MESSAGE;
         }
-      } catch (_e) {
-        // It's not a nested JSON error, so we just use the message as is.
+        return text;
       }
-      return `API Error: ${finalMessage} (Status: ${error.error.status})`;
+    } catch (_e) {
+      // Not a valid JSON, fall through and return the original message.
     }
-  } catch (_e) {
-    // Not a valid JSON, fall through and return the original message.
+    return `[API Error: ${error}]`;
   }
 
-  return errorMessage;
+  return '[API Error: An unknown error occurred.]';
 }