chore(compiler): Enable strict property access TS compiler flag. (#6255)

Co-authored-by: Jacob Richman <[email protected]>

30 files changed, 175 insertions, 161 deletions

diff --git a/packages/core/src/code_assist/oauth2.test.ts b/packages/core/src/code_assist/oauth2.test.ts
index 77a8fb90..821788d5 100644
--- a/packages/core/src/code_assist/oauth2.test.ts
+++ b/packages/core/src/code_assist/oauth2.test.ts
@@ -57,9 +57,7 @@ describe('oauth2', () => {
     fs.rmSync(tempHomeDir, { recursive: true, force: true });
     vi.clearAllMocks();
     resetOauthClientForTesting();
-    delete process.env.CLOUD_SHELL;
-    delete process.env.GOOGLE_GENAI_USE_GCA;
-    delete process.env.GOOGLE_CLOUD_ACCESS_TOKEN;
+    vi.unstubAllEnvs();
   });
 
   it('should perform a web login', async () => {
@@ -328,8 +326,8 @@ describe('oauth2', () => {
 
   describe('with GCP environment variables', () => {
     it('should use GOOGLE_CLOUD_ACCESS_TOKEN when GOOGLE_GENAI_USE_GCA is true', async () => {
-      process.env.GOOGLE_GENAI_USE_GCA = 'true';
-      process.env.GOOGLE_CLOUD_ACCESS_TOKEN = 'gcp-access-token';
+      vi.stubEnv('GOOGLE_GENAI_USE_GCA', 'true');
+      vi.stubEnv('GOOGLE_CLOUD_ACCESS_TOKEN', 'gcp-access-token');
 
       const mockSetCredentials = vi.fn();
       const mockGetAccessToken = vi
@@ -387,7 +385,7 @@ describe('oauth2', () => {
     });
 
     it('should not use GCP token if GOOGLE_CLOUD_ACCESS_TOKEN is not set', async () => {
-      process.env.GOOGLE_GENAI_USE_GCA = 'true';
+      vi.stubEnv('GOOGLE_GENAI_USE_GCA', 'true');
 
       const mockSetCredentials = vi.fn();
       const mockGetAccessToken = vi
@@ -418,7 +416,7 @@ describe('oauth2', () => {
     });
 
     it('should not use GCP token if GOOGLE_GENAI_USE_GCA is not set', async () => {
-      process.env.GOOGLE_CLOUD_ACCESS_TOKEN = 'gcp-access-token';
+      vi.stubEnv('GOOGLE_CLOUD_ACCESS_TOKEN', 'gcp-access-token');
 
       const mockSetCredentials = vi.fn();
       const mockGetAccessToken = vi
diff --git a/packages/core/src/code_assist/oauth2.ts b/packages/core/src/code_assist/oauth2.ts
index f9518cbe..a4dcf8a7 100644
--- a/packages/core/src/code_assist/oauth2.ts
+++ b/packages/core/src/code_assist/oauth2.ts
@@ -81,11 +81,11 @@ async function initOauthClient(
   });
 
   if (
-    process.env.GOOGLE_GENAI_USE_GCA &&
-    process.env.GOOGLE_CLOUD_ACCESS_TOKEN
+    process.env['GOOGLE_GENAI_USE_GCA'] &&
+    process.env['GOOGLE_CLOUD_ACCESS_TOKEN']
   ) {
     client.setCredentials({
-      access_token: process.env.GOOGLE_CLOUD_ACCESS_TOKEN,
+      access_token: process.env['GOOGLE_CLOUD_ACCESS_TOKEN'],
     });
     await fetchAndCacheUserInfo(client);
     return client;
@@ -248,7 +248,7 @@ async function authWithUserCode(client: OAuth2Client): Promise<boolean> {
 async function authWithWeb(client: OAuth2Client): Promise<OauthWebLogin> {
   const port = await getAvailablePort();
   // The hostname used for the HTTP server binding (e.g., '0.0.0.0' in Docker).
-  const host = process.env.OAUTH_CALLBACK_HOST || 'localhost';
+  const host = process.env['OAUTH_CALLBACK_HOST'] || 'localhost';
   // The `redirectUri` sent to Google's authorization server MUST use a loopback IP literal
   // (i.e., 'localhost' or '127.0.0.1'). This is a strict security policy for credentials of
   // type 'Desktop app' or 'Web application' (when using loopback flow) to mitigate
@@ -323,7 +323,7 @@ export function getAvailablePort(): Promise<number> {
   return new Promise((resolve, reject) => {
     let port = 0;
     try {
-      const portStr = process.env.OAUTH_CALLBACK_PORT;
+      const portStr = process.env['OAUTH_CALLBACK_PORT'];
       if (portStr) {
         port = parseInt(portStr, 10);
         if (isNaN(port) || port <= 0 || port > 65535) {
@@ -353,7 +353,8 @@ export function getAvailablePort(): Promise<number> {
 async function loadCachedCredentials(client: OAuth2Client): Promise<boolean> {
   try {
     const keyFile =
-      process.env.GOOGLE_APPLICATION_CREDENTIALS || getCachedCredentialPath();
+      process.env['GOOGLE_APPLICATION_CREDENTIALS'] ||
+      getCachedCredentialPath();
 
     const creds = await fs.readFile(keyFile, 'utf-8');
     client.setCredentials(JSON.parse(creds));
diff --git a/packages/core/src/code_assist/server.ts b/packages/core/src/code_assist/server.ts
index 08339bdc..470143a6 100644
--- a/packages/core/src/code_assist/server.ts
+++ b/packages/core/src/code_assist/server.ts
@@ -214,7 +214,8 @@ export class CodeAssistServer implements ContentGenerator {
   }
 
   getMethodUrl(method: string): string {
-    const endpoint = process.env.CODE_ASSIST_ENDPOINT ?? CODE_ASSIST_ENDPOINT;
+    const endpoint =
+      process.env['CODE_ASSIST_ENDPOINT'] ?? CODE_ASSIST_ENDPOINT;
     return `${endpoint}/${CODE_ASSIST_API_VERSION}:${method}`;
   }
 }
diff --git a/packages/core/src/code_assist/setup.test.ts b/packages/core/src/code_assist/setup.test.ts
index cba051dd..61a7431a 100644
--- a/packages/core/src/code_assist/setup.test.ts
+++ b/packages/core/src/code_assist/setup.test.ts
@@ -4,7 +4,7 @@
  * SPDX-License-Identifier: Apache-2.0
  */
 
-import { describe, it, expect, vi, beforeEach } from 'vitest';
+import { describe, it, expect, vi, beforeEach, afterEach } from 'vitest';
 import { setupUser, ProjectIdRequiredError } from './setup.js';
 import { CodeAssistServer } from '../code_assist/server.js';
 import { OAuth2Client } from 'google-auth-library';
@@ -50,8 +50,12 @@ describe('setupUser for existing user', () => {
     );
   });
 
+  afterEach(() => {
+    vi.unstubAllEnvs();
+  });
+
   it('should use GOOGLE_CLOUD_PROJECT when set and project from server is undefined', async () => {
-    process.env.GOOGLE_CLOUD_PROJECT = 'test-project';
+    vi.stubEnv('GOOGLE_CLOUD_PROJECT', 'test-project');
     mockLoad.mockResolvedValue({
       currentTier: mockPaidTier,
     });
@@ -66,7 +70,7 @@ describe('setupUser for existing user', () => {
   });
 
   it('should ignore GOOGLE_CLOUD_PROJECT when project from server is set', async () => {
-    process.env.GOOGLE_CLOUD_PROJECT = 'test-project';
+    vi.stubEnv('GOOGLE_CLOUD_PROJECT', 'test-project');
     mockLoad.mockResolvedValue({
       cloudaicompanionProject: 'server-project',
       currentTier: mockPaidTier,
@@ -86,7 +90,7 @@ describe('setupUser for existing user', () => {
   });
 
   it('should throw ProjectIdRequiredError when no project ID is available', async () => {
-    delete process.env.GOOGLE_CLOUD_PROJECT;
+    vi.stubEnv('GOOGLE_CLOUD_PROJECT', '');
     // And the server itself requires a project ID internally
     vi.mocked(CodeAssistServer).mockImplementation(() => {
       throw new ProjectIdRequiredError();
@@ -122,8 +126,12 @@ describe('setupUser for new user', () => {
     );
   });
 
+  afterEach(() => {
+    vi.unstubAllEnvs();
+  });
+
   it('should use GOOGLE_CLOUD_PROJECT when set and onboard a new paid user', async () => {
-    process.env.GOOGLE_CLOUD_PROJECT = 'test-project';
+    vi.stubEnv('GOOGLE_CLOUD_PROJECT', 'test-project');
     mockLoad.mockResolvedValue({
       allowedTiers: [mockPaidTier],
     });
@@ -153,7 +161,7 @@ describe('setupUser for new user', () => {
   });
 
   it('should onboard a new free user when GOOGLE_CLOUD_PROJECT is not set', async () => {
-    delete process.env.GOOGLE_CLOUD_PROJECT;
+    vi.stubEnv('GOOGLE_CLOUD_PROJECT', '');
     mockLoad.mockResolvedValue({
       allowedTiers: [mockFreeTier],
     });
@@ -182,7 +190,7 @@ describe('setupUser for new user', () => {
   });
 
   it('should use GOOGLE_CLOUD_PROJECT when onboard response has no project ID', async () => {
-    process.env.GOOGLE_CLOUD_PROJECT = 'test-project';
+    vi.stubEnv('GOOGLE_CLOUD_PROJECT', 'test-project');
     mockLoad.mockResolvedValue({
       allowedTiers: [mockPaidTier],
     });
@@ -200,7 +208,7 @@ describe('setupUser for new user', () => {
   });
 
   it('should throw ProjectIdRequiredError when no project ID is available', async () => {
-    delete process.env.GOOGLE_CLOUD_PROJECT;
+    vi.stubEnv('GOOGLE_CLOUD_PROJECT', '');
     mockLoad.mockResolvedValue({
       allowedTiers: [mockPaidTier],
     });
diff --git a/packages/core/src/code_assist/setup.ts b/packages/core/src/code_assist/setup.ts
index 2e460c98..d563301d 100644
--- a/packages/core/src/code_assist/setup.ts
+++ b/packages/core/src/code_assist/setup.ts
@@ -33,7 +33,7 @@ export interface UserData {
  * @returns the user's actual project id
  */
 export async function setupUser(client: OAuth2Client): Promise<UserData> {
-  const projectId = process.env.GOOGLE_CLOUD_PROJECT || undefined;
+  const projectId = process.env['GOOGLE_CLOUD_PROJECT'] || undefined;
   const caServer = new CodeAssistServer(client, projectId, {}, '', undefined);
   const coreClientMetadata: ClientMetadata = {
     ideType: 'IDE_UNSPECIFIED',
diff --git a/packages/core/src/config/config.ts b/packages/core/src/config/config.ts
index 49f9ab45..acaf5eb1 100644
--- a/packages/core/src/config/config.ts
+++ b/packages/core/src/config/config.ts
@@ -458,7 +458,7 @@ export class Config {
 
   isRestrictiveSandbox(): boolean {
     const sandboxConfig = this.getSandbox();
-    const seatbeltProfile = process.env.SEATBELT_PROFILE;
+    const seatbeltProfile = process.env['SEATBELT_PROFILE'];
     return (
       !!sandboxConfig &&
       sandboxConfig.command === 'sandbox-exec' &&
diff --git a/packages/core/src/core/client.ts b/packages/core/src/core/client.ts
index a2abd0d0..66f3e08f 100644
--- a/packages/core/src/core/client.ts
+++ b/packages/core/src/core/client.ts
@@ -286,7 +286,7 @@ export class GeminiClient {
       const contextData: Record<string, unknown> = {};
 
       if (activeFile) {
-        contextData.activeFile = {
+        contextData['activeFile'] = {
           path: activeFile.path,
           cursor: activeFile.cursor
             ? {
@@ -299,7 +299,7 @@ export class GeminiClient {
       }
 
       if (otherOpenFiles.length > 0) {
-        contextData.otherOpenFiles = otherOpenFiles;
+        contextData['otherOpenFiles'] = otherOpenFiles;
       }
 
       if (Object.keys(contextData).length === 0) {
@@ -345,7 +345,7 @@ export class GeminiClient {
         }
       }
       if (openedFiles.length > 0) {
-        changes.filesOpened = openedFiles;
+        changes['filesOpened'] = openedFiles;
       }
 
       const closedFiles: string[] = [];
@@ -355,7 +355,7 @@ export class GeminiClient {
         }
       }
       if (closedFiles.length > 0) {
-        changes.filesClosed = closedFiles;
+        changes['filesClosed'] = closedFiles;
       }
 
       const lastActiveFile = (
@@ -367,7 +367,7 @@ export class GeminiClient {
 
       if (currentActiveFile) {
         if (!lastActiveFile || lastActiveFile.path !== currentActiveFile.path) {
-          changes.activeFileChanged = {
+          changes['activeFileChanged'] = {
             path: currentActiveFile.path,
             cursor: currentActiveFile.cursor
               ? {
@@ -386,7 +386,7 @@ export class GeminiClient {
               lastCursor.line !== currentCursor.line ||
               lastCursor.character !== currentCursor.character)
           ) {
-            changes.cursorMoved = {
+            changes['cursorMoved'] = {
               path: currentActiveFile.path,
               cursor: {
                 line: currentCursor.line,
@@ -398,14 +398,14 @@ export class GeminiClient {
           const lastSelectedText = lastActiveFile.selectedText || '';
           const currentSelectedText = currentActiveFile.selectedText || '';
           if (lastSelectedText !== currentSelectedText) {
-            changes.selectionChanged = {
+            changes['selectionChanged'] = {
               path: currentActiveFile.path,
               selectedText: currentSelectedText,
             };
           }
         }
       } else if (lastActiveFile) {
-        changes.activeFileChanged = {
+        changes['activeFileChanged'] = {
           path: null,
           previousPath: lastActiveFile.path,
         };
@@ -415,7 +415,7 @@ export class GeminiClient {
         return { contextParts: [], newIdeContext: currentIdeContext };
       }
 
-      delta.changes = changes;
+      delta['changes'] = changes;
       const jsonString = JSON.stringify(delta, null, 2);
       const contextParts = [
         "Here is a summary of changes in the user's editor context, in JSON format. This is for your information only.",
diff --git a/packages/core/src/core/contentGenerator.test.ts b/packages/core/src/core/contentGenerator.test.ts
index e89b5bc7..b92e8046 100644
--- a/packages/core/src/core/contentGenerator.test.ts
+++ b/packages/core/src/core/contentGenerator.test.ts
@@ -4,7 +4,7 @@
  * SPDX-License-Identifier: Apache-2.0
  */
 
-import { describe, it, expect, vi, beforeEach, afterAll } from 'vitest';
+import { describe, it, expect, vi, beforeEach, afterEach } from 'vitest';
 import {
   createContentGenerator,
   AuthType,
@@ -72,7 +72,6 @@ describe('createContentGenerator', () => {
 });
 
 describe('createContentGeneratorConfig', () => {
-  const originalEnv = process.env;
   const mockConfig = {
     getModel: vi.fn().mockReturnValue('gemini-pro'),
     setModel: vi.fn(),
@@ -83,18 +82,15 @@ describe('createContentGeneratorConfig', () => {
   beforeEach(() => {
     // Reset modules to re-evaluate imports and environment variables
     vi.resetModules();
-    // Restore process.env before each test
-    process.env = { ...originalEnv };
     vi.clearAllMocks();
   });
 
-  afterAll(() => {
-    // Restore original process.env after all tests
-    process.env = originalEnv;
+  afterEach(() => {
+    vi.unstubAllEnvs();
   });
 
   it('should configure for Gemini using GEMINI_API_KEY when set', async () => {
-    process.env.GEMINI_API_KEY = 'env-gemini-key';
+    vi.stubEnv('GEMINI_API_KEY', 'env-gemini-key');
     const config = await createContentGeneratorConfig(
       mockConfig,
       AuthType.USE_GEMINI,
@@ -104,7 +100,7 @@ describe('createContentGeneratorConfig', () => {
   });
 
   it('should not configure for Gemini if GEMINI_API_KEY is empty', async () => {
-    process.env.GEMINI_API_KEY = '';
+    vi.stubEnv('GEMINI_API_KEY', '');
     const config = await createContentGeneratorConfig(
       mockConfig,
       AuthType.USE_GEMINI,
@@ -114,7 +110,7 @@ describe('createContentGeneratorConfig', () => {
   });
 
   it('should configure for Vertex AI using GOOGLE_API_KEY when set', async () => {
-    process.env.GOOGLE_API_KEY = 'env-google-key';
+    vi.stubEnv('GOOGLE_API_KEY', 'env-google-key');
     const config = await createContentGeneratorConfig(
       mockConfig,
       AuthType.USE_VERTEX_AI,
@@ -124,8 +120,8 @@ describe('createContentGeneratorConfig', () => {
   });
 
   it('should configure for Vertex AI using GCP project and location when set', async () => {
-    process.env.GOOGLE_CLOUD_PROJECT = 'env-gcp-project';
-    process.env.GOOGLE_CLOUD_LOCATION = 'env-gcp-location';
+    vi.stubEnv('GOOGLE_CLOUD_PROJECT', 'env-gcp-project');
+    vi.stubEnv('GOOGLE_CLOUD_LOCATION', 'env-gcp-location');
     const config = await createContentGeneratorConfig(
       mockConfig,
       AuthType.USE_VERTEX_AI,
@@ -135,9 +131,9 @@ describe('createContentGeneratorConfig', () => {
   });
 
   it('should not configure for Vertex AI if required env vars are empty', async () => {
-    process.env.GOOGLE_API_KEY = '';
-    process.env.GOOGLE_CLOUD_PROJECT = '';
-    process.env.GOOGLE_CLOUD_LOCATION = '';
+    vi.stubEnv('GOOGLE_API_KEY', '');
+    vi.stubEnv('GOOGLE_CLOUD_PROJECT', '');
+    vi.stubEnv('GOOGLE_CLOUD_LOCATION', '');
     const config = await createContentGeneratorConfig(
       mockConfig,
       AuthType.USE_VERTEX_AI,
diff --git a/packages/core/src/core/contentGenerator.ts b/packages/core/src/core/contentGenerator.ts
index 599a569b..19b285c7 100644
--- a/packages/core/src/core/contentGenerator.ts
+++ b/packages/core/src/core/contentGenerator.ts
@@ -60,10 +60,10 @@ export function createContentGeneratorConfig(
   config: Config,
   authType: AuthType | undefined,
 ): ContentGeneratorConfig {
-  const geminiApiKey = process.env.GEMINI_API_KEY || undefined;
-  const googleApiKey = process.env.GOOGLE_API_KEY || undefined;
-  const googleCloudProject = process.env.GOOGLE_CLOUD_PROJECT || undefined;
-  const googleCloudLocation = process.env.GOOGLE_CLOUD_LOCATION || undefined;
+  const geminiApiKey = process.env['GEMINI_API_KEY'] || undefined;
+  const googleApiKey = process.env['GOOGLE_API_KEY'] || undefined;
+  const googleCloudProject = process.env['GOOGLE_CLOUD_PROJECT'] || undefined;
+  const googleCloudLocation = process.env['GOOGLE_CLOUD_LOCATION'] || undefined;
 
   // Use runtime model from config if available; otherwise, fall back to parameter or default
   const effectiveModel = config.getModel() || DEFAULT_GEMINI_MODEL;
@@ -107,7 +107,7 @@ export async function createContentGenerator(
   gcConfig: Config,
   sessionId?: string,
 ): Promise<ContentGenerator> {
-  const version = process.env.CLI_VERSION || process.version;
+  const version = process.env['CLI_VERSION'] || process.version;
   const httpOptions = {
     headers: {
       'User-Agent': `GeminiCLI/${version} (${process.platform}; ${process.arch})`,
diff --git a/packages/core/src/core/coreToolScheduler.ts b/packages/core/src/core/coreToolScheduler.ts
index 0d442f9d..1a031de5 100644
--- a/packages/core/src/core/coreToolScheduler.ts
+++ b/packages/core/src/core/coreToolScheduler.ts
@@ -171,10 +171,10 @@ export function convertToFunctionResponse(
 
   // After this point, contentToProcess is a single Part object.
   if (contentToProcess.functionResponse) {
-    if (contentToProcess.functionResponse.response?.content) {
+    if (contentToProcess.functionResponse.response?.['content']) {
       const stringifiedOutput =
         getResponseTextFromParts(
-          contentToProcess.functionResponse.response.content as Part[],
+          contentToProcess.functionResponse.response['content'] as Part[],
         ) || '';
       return createFunctionResponsePart(callId, toolName, stringifiedOutput);
     }
diff --git a/packages/core/src/core/prompts.ts b/packages/core/src/core/prompts.ts
index 95c55143..b4b9a979 100644
--- a/packages/core/src/core/prompts.ts
+++ b/packages/core/src/core/prompts.ts
@@ -24,7 +24,7 @@ export function getCoreSystemPrompt(userMemory?: string): string {
   // default path is .gemini/system.md but can be modified via custom path in GEMINI_SYSTEM_MD
   let systemMdEnabled = false;
   let systemMdPath = path.resolve(path.join(GEMINI_CONFIG_DIR, 'system.md'));
-  const systemMdVar = process.env.GEMINI_SYSTEM_MD;
+  const systemMdVar = process.env['GEMINI_SYSTEM_MD'];
   if (systemMdVar) {
     const systemMdVarLower = systemMdVar.toLowerCase();
     if (!['0', 'false'].includes(systemMdVarLower)) {
@@ -121,8 +121,8 @@ When requested to perform tasks like fixing bugs, adding features, refactoring,
 
 ${(function () {
   // Determine sandbox status based on environment variables
-  const isSandboxExec = process.env.SANDBOX === 'sandbox-exec';
-  const isGenericSandbox = !!process.env.SANDBOX; // Check if SANDBOX is set to any non-empty value
+  const isSandboxExec = process.env['SANDBOX'] === 'sandbox-exec';
+  const isGenericSandbox = !!process.env['SANDBOX']; // Check if SANDBOX is set to any non-empty value
 
   if (isSandboxExec) {
     return `
@@ -266,7 +266,7 @@ Your core function is efficient and safe assistance. Balance extreme conciseness
 `.trim();
 
   // if GEMINI_WRITE_SYSTEM_MD is set (and not 0|false), write base system prompt to file
-  const writeSystemMdVar = process.env.GEMINI_WRITE_SYSTEM_MD;
+  const writeSystemMdVar = process.env['GEMINI_WRITE_SYSTEM_MD'];
   if (writeSystemMdVar) {
     const writeSystemMdVarLower = writeSystemMdVar.toLowerCase();
     if (!['0', 'false'].includes(writeSystemMdVarLower)) {
diff --git a/packages/core/src/ide/detect-ide.ts b/packages/core/src/ide/detect-ide.ts
index 5cc3cb56..5eca5429 100644
--- a/packages/core/src/ide/detect-ide.ts
+++ b/packages/core/src/ide/detect-ide.ts
@@ -63,28 +63,28 @@ export function getIdeInfo(ide: DetectedIde): IdeInfo {
 
 export function detectIde(): DetectedIde | undefined {
   // Only VSCode-based integrations are currently supported.
-  if (process.env.TERM_PROGRAM !== 'vscode') {
+  if (process.env['TERM_PROGRAM'] !== 'vscode') {
     return undefined;
   }
-  if (process.env.__COG_BASHRC_SOURCED) {
+  if (process.env['__COG_BASHRC_SOURCED']) {
     return DetectedIde.Devin;
   }
-  if (process.env.REPLIT_USER) {
+  if (process.env['REPLIT_USER']) {
     return DetectedIde.Replit;
   }
-  if (process.env.CURSOR_TRACE_ID) {
+  if (process.env['CURSOR_TRACE_ID']) {
     return DetectedIde.Cursor;
   }
-  if (process.env.CODESPACES) {
+  if (process.env['CODESPACES']) {
     return DetectedIde.Codespaces;
   }
-  if (process.env.EDITOR_IN_CLOUD_SHELL || process.env.CLOUD_SHELL) {
+  if (process.env['EDITOR_IN_CLOUD_SHELL'] || process.env['CLOUD_SHELL']) {
     return DetectedIde.CloudShell;
   }
-  if (process.env.TERM_PRODUCT === 'Trae') {
+  if (process.env['TERM_PRODUCT'] === 'Trae') {
     return DetectedIde.Trae;
   }
-  if (process.env.FIREBASE_DEPLOY_AGENT || process.env.MONOSPACE_ENV) {
+  if (process.env['FIREBASE_DEPLOY_AGENT'] || process.env['MONOSPACE_ENV']) {
     return DetectedIde.FirebaseStudio;
   }
   return DetectedIde.VSCode;
diff --git a/packages/core/src/ide/ide-installer.ts b/packages/core/src/ide/ide-installer.ts
index dcfe9bee..4a771c67 100644
--- a/packages/core/src/ide/ide-installer.ts
+++ b/packages/core/src/ide/ide-installer.ts
@@ -59,7 +59,7 @@ async function findVsCodeCommand(): Promise<string | null> {
     // Windows
     locations.push(
       path.join(
-        process.env.ProgramFiles || 'C:\\Program Files',
+        process.env['ProgramFiles'] || 'C:\\Program Files',
         'Microsoft VS Code',
         'bin',
         'code.cmd',
diff --git a/packages/core/src/services/loopDetectionService.ts b/packages/core/src/services/loopDetectionService.ts
index f89e00da..8e94ac69 100644
--- a/packages/core/src/services/loopDetectionService.ts
+++ b/packages/core/src/services/loopDetectionService.ts
@@ -367,10 +367,10 @@ Please analyze the conversation history to determine the possibility that the co
       return false;
     }
 
-    if (typeof result.confidence === 'number') {
-      if (result.confidence > 0.9) {
-        if (typeof result.reasoning === 'string' && result.reasoning) {
-          console.warn(result.reasoning);
+    if (typeof result['confidence'] === 'number') {
+      if (result['confidence'] > 0.9) {
+        if (typeof result['reasoning'] === 'string' && result['reasoning']) {
+          console.warn(result['reasoning']);
         }
         logLoopDetected(
           this.config,
@@ -381,7 +381,7 @@ Please analyze the conversation history to determine the possibility that the co
         this.llmCheckInterval = Math.round(
           MIN_LLM_CHECK_INTERVAL +
             (MAX_LLM_CHECK_INTERVAL - MIN_LLM_CHECK_INTERVAL) *
-              (1 - result.confidence),
+              (1 - result['confidence']),
         );
       }
     }
diff --git a/packages/core/src/telemetry/clearcut-logger/clearcut-logger.ts b/packages/core/src/telemetry/clearcut-logger/clearcut-logger.ts
index 60a31ae7..200a1a0d 100644
--- a/packages/core/src/telemetry/clearcut-logger/clearcut-logger.ts
+++ b/packages/core/src/telemetry/clearcut-logger/clearcut-logger.ts
@@ -87,11 +87,11 @@ export interface LogRequest {
  * methods might have in their runtimes.
  */
 function determineSurface(): string {
-  if (process.env.SURFACE) {
-    return process.env.SURFACE;
-  } else if (process.env.GITHUB_SHA) {
+  if (process.env['SURFACE']) {
+    return process.env['SURFACE'];
+  } else if (process.env['GITHUB_SHA']) {
     return 'GitHub';
-  } else if (process.env.TERM_PROGRAM === 'vscode') {
+  } else if (process.env['TERM_PROGRAM'] === 'vscode') {
     return detectIde() || DetectedIde.VSCode;
   } else {
     return 'SURFACE_NOT_SET';
diff --git a/packages/core/src/telemetry/loggers.ts b/packages/core/src/telemetry/loggers.ts
index d7a81203..afc92807 100644
--- a/packages/core/src/telemetry/loggers.ts
+++ b/packages/core/src/telemetry/loggers.ts
@@ -98,7 +98,7 @@ export function logUserPrompt(config: Config, event: UserPromptEvent): void {
   };
 
   if (shouldLogUserPrompts(config)) {
-    attributes.prompt = event.prompt;
+    attributes['prompt'] = event.prompt;
   }
 
   const logger = logs.getLogger(SERVICE_NAME);
@@ -247,7 +247,7 @@ export function logApiResponse(config: Config, event: ApiResponseEvent): void {
     'event.timestamp': new Date().toISOString(),
   };
   if (event.response_text) {
-    attributes.response_text = event.response_text;
+    attributes['response_text'] = event.response_text;
   }
   if (event.error) {
     attributes['error.message'] = event.error;
diff --git a/packages/core/src/telemetry/metrics.ts b/packages/core/src/telemetry/metrics.ts
index 1e4509da..a0996410 100644
--- a/packages/core/src/telemetry/metrics.ts
+++ b/packages/core/src/telemetry/metrics.ts
@@ -197,14 +197,14 @@ export function recordFileOperationMetric(
     ...getCommonAttributes(config),
     operation,
   };
-  if (lines !== undefined) attributes.lines = lines;
-  if (mimetype !== undefined) attributes.mimetype = mimetype;
-  if (extension !== undefined) attributes.extension = extension;
+  if (lines !== undefined) attributes['lines'] = lines;
+  if (mimetype !== undefined) attributes['mimetype'] = mimetype;
+  if (extension !== undefined) attributes['extension'] = extension;
   if (diffStat !== undefined) {
-    attributes.ai_added_lines = diffStat.ai_added_lines;
-    attributes.ai_removed_lines = diffStat.ai_removed_lines;
-    attributes.user_added_lines = diffStat.user_added_lines;
-    attributes.user_removed_lines = diffStat.user_removed_lines;
+    attributes['ai_added_lines'] = diffStat.ai_added_lines;
+    attributes['ai_removed_lines'] = diffStat.ai_removed_lines;
+    attributes['user_added_lines'] = diffStat.user_added_lines;
+    attributes['user_removed_lines'] = diffStat.user_removed_lines;
   }
   fileOperationCounter.add(1, attributes);
 }
diff --git a/packages/core/src/tools/mcp-client.ts b/packages/core/src/tools/mcp-client.ts
index 837b91fc..87d38815 100644
--- a/packages/core/src/tools/mcp-client.ts
+++ b/packages/core/src/tools/mcp-client.ts
@@ -448,7 +448,7 @@ export function hasValidTypes(schema: unknown): boolean {
 
   const s = schema as Record<string, unknown>;
 
-  if (!s.type) {
+  if (!s['type']) {
     // These keywords contain an array of schemas that should be validated.
     //
     // If no top level type was given, then they must each have a type.
@@ -470,9 +470,9 @@ export function hasValidTypes(schema: unknown): boolean {
     if (!hasSubSchema) return false;
   }
 
-  if (s.type === 'object' && s.properties) {
-    if (typeof s.properties === 'object' && s.properties !== null) {
-      for (const prop of Object.values(s.properties)) {
+  if (s['type'] === 'object' && s['properties']) {
+    if (typeof s['properties'] === 'object' && s['properties'] !== null) {
+      for (const prop of Object.values(s['properties'])) {
         if (!hasValidTypes(prop)) {
           return false;
         }
@@ -480,8 +480,8 @@ export function hasValidTypes(schema: unknown): boolean {
     }
   }
 
-  if (s.type === 'array' && s.items) {
-    if (!hasValidTypes(s.items)) {
+  if (s['type'] === 'array' && s['items']) {
+    if (!hasValidTypes(s['items'])) {
       return false;
     }
   }
@@ -1046,7 +1046,7 @@ export async function connectToMcpServer(
         conciseError = `Connection failed for '${mcpServerName}': ${errorMessage}`;
       }
 
-      if (process.env.SANDBOX) {
+      if (process.env['SANDBOX']) {
         conciseError += ` (check sandbox availability)`;
       }
 
diff --git a/packages/core/src/tools/mcp-tool.ts b/packages/core/src/tools/mcp-tool.ts
index 88e89c85..64952dd1 100644
--- a/packages/core/src/tools/mcp-tool.ts
+++ b/packages/core/src/tools/mcp-tool.ts
@@ -271,7 +271,7 @@ function transformResourceLinkBlock(block: McpResourceLinkBlock): Part {
  */
 function transformMcpContentToParts(sdkResponse: Part[]): Part[] {
   const funcResponse = sdkResponse?.[0]?.functionResponse;
-  const mcpContent = funcResponse?.response?.content as McpContentBlock[];
+  const mcpContent = funcResponse?.response?.['content'] as McpContentBlock[];
   const toolName = funcResponse?.name || 'unknown tool';
 
   if (!Array.isArray(mcpContent)) {
@@ -308,8 +308,9 @@ function transformMcpContentToParts(sdkResponse: Part[]): Part[] {
  * @returns A formatted string representing the tool's output.
  */
 function getStringifiedResultForDisplay(rawResponse: Part[]): string {
-  const mcpContent = rawResponse?.[0]?.functionResponse?.response
-    ?.content as McpContentBlock[];
+  const mcpContent = rawResponse?.[0]?.functionResponse?.response?.[
+    'content'
+  ] as McpContentBlock[];
 
   if (!Array.isArray(mcpContent)) {
     return '```json\n' + JSON.stringify(rawResponse, null, 2) + '\n```';
diff --git a/packages/core/src/utils/browser.ts b/packages/core/src/utils/browser.ts
index a9b2b013..35ee7461 100644
--- a/packages/core/src/utils/browser.ts
+++ b/packages/core/src/utils/browser.ts
@@ -15,19 +15,22 @@ export function shouldAttemptBrowserLaunch(): boolean {
   // A list of browser names that indicate we should not attempt to open a
   // web browser for the user.
   const browserBlocklist = ['www-browser'];
-  const browserEnv = process.env.BROWSER;
+  const browserEnv = process.env['BROWSER'];
   if (browserEnv && browserBlocklist.includes(browserEnv)) {
     return false;
   }
   // Common environment variables used in CI/CD or other non-interactive shells.
-  if (process.env.CI || process.env.DEBIAN_FRONTEND === 'noninteractive') {
+  if (
+    process.env['CI'] ||
+    process.env['DEBIAN_FRONTEND'] === 'noninteractive'
+  ) {
     return false;
   }
 
   // The presence of SSH_CONNECTION indicates a remote session.
   // We should not attempt to launch a browser unless a display is explicitly available
   // (checked below for Linux).
-  const isSSH = !!process.env.SSH_CONNECTION;
+  const isSSH = !!process.env['SSH_CONNECTION'];
 
   // On Linux, the presence of a display server is a strong indicator of a GUI.
   if (process.platform === 'linux') {
diff --git a/packages/core/src/utils/editCorrector.ts b/packages/core/src/utils/editCorrector.ts
index faa52b51..0d857409 100644
--- a/packages/core/src/utils/editCorrector.ts
+++ b/packages/core/src/utils/editCorrector.ts
@@ -119,7 +119,7 @@ async function findLastEditTimestamp(
         const { response } = part.functionResponse;
         if (response && !('error' in response) && 'output' in response) {
           id = part.functionResponse.id;
-          content = response.output;
+          content = response['output'];
         }
       }
 
@@ -411,10 +411,10 @@ Return ONLY the corrected target snippet in the specified JSON format with the k
 
     if (
       result &&
-      typeof result.corrected_target_snippet === 'string' &&
-      result.corrected_target_snippet.length > 0
+      typeof result['corrected_target_snippet'] === 'string' &&
+      result['corrected_target_snippet'].length > 0
     ) {
-      return result.corrected_target_snippet;
+      return result['corrected_target_snippet'];
     } else {
       return problematicSnippet;
     }
@@ -499,10 +499,10 @@ Return ONLY the corrected string in the specified JSON format with the key 'corr
 
     if (
       result &&
-      typeof result.corrected_new_string === 'string' &&
-      result.corrected_new_string.length > 0
+      typeof result['corrected_new_string'] === 'string' &&
+      result['corrected_new_string'].length > 0
     ) {
-      return result.corrected_new_string;
+      return result['corrected_new_string'];
     } else {
       return originalNewString;
     }
@@ -568,10 +568,10 @@ Return ONLY the corrected string in the specified JSON format with the key 'corr
 
     if (
       result &&
-      typeof result.corrected_new_string_escaping === 'string' &&
-      result.corrected_new_string_escaping.length > 0
+      typeof result['corrected_new_string_escaping'] === 'string' &&
+      result['corrected_new_string_escaping'].length > 0
     ) {
-      return result.corrected_new_string_escaping;
+      return result['corrected_new_string_escaping'];
     } else {
       return potentiallyProblematicNewString;
     }
@@ -634,10 +634,10 @@ Return ONLY the corrected string in the specified JSON format with the key 'corr
 
     if (
       result &&
-      typeof result.corrected_string_escaping === 'string' &&
-      result.corrected_string_escaping.length > 0
+      typeof result['corrected_string_escaping'] === 'string' &&
+      result['corrected_string_escaping'].length > 0
     ) {
-      return result.corrected_string_escaping;
+      return result['corrected_string_escaping'];
     } else {
       return potentiallyProblematicString;
     }
diff --git a/packages/core/src/utils/editor.test.ts b/packages/core/src/utils/editor.test.ts
index afdc2b24..fcf50f9c 100644
--- a/packages/core/src/utils/editor.test.ts
+++ b/packages/core/src/utils/editor.test.ts
@@ -33,7 +33,7 @@ const originalPlatform = process.platform;
 describe('editor utils', () => {
   beforeEach(() => {
     vi.clearAllMocks();
-    delete process.env.SANDBOX;
+    vi.unstubAllEnvs();
     Object.defineProperty(process, 'platform', {
       value: originalPlatform,
       writable: true,
@@ -42,7 +42,7 @@ describe('editor utils', () => {
 
   afterEach(() => {
     vi.restoreAllMocks();
-    delete process.env.SANDBOX;
+    vi.unstubAllEnvs();
     Object.defineProperty(process, 'platform', {
       value: originalPlatform,
       writable: true,
@@ -461,7 +461,7 @@ describe('editor utils', () => {
 
   describe('allowEditorTypeInSandbox', () => {
     it('should allow vim in sandbox mode', () => {
-      process.env.SANDBOX = 'sandbox';
+      vi.stubEnv('SANDBOX', 'sandbox');
       expect(allowEditorTypeInSandbox('vim')).toBe(true);
     });
 
@@ -470,7 +470,7 @@ describe('editor utils', () => {
     });
 
     it('should allow emacs in sandbox mode', () => {
-      process.env.SANDBOX = 'sandbox';
+      vi.stubEnv('SANDBOX', 'sandbox');
       expect(allowEditorTypeInSandbox('emacs')).toBe(true);
     });
 
@@ -479,7 +479,7 @@ describe('editor utils', () => {
     });
 
     it('should allow neovim in sandbox mode', () => {
-      process.env.SANDBOX = 'sandbox';
+      vi.stubEnv('SANDBOX', 'sandbox');
       expect(allowEditorTypeInSandbox('neovim')).toBe(true);
     });
 
@@ -496,7 +496,7 @@ describe('editor utils', () => {
     ];
     for (const editor of guiEditors) {
       it(`should not allow ${editor} in sandbox mode`, () => {
-        process.env.SANDBOX = 'sandbox';
+        vi.stubEnv('SANDBOX', 'sandbox');
         expect(allowEditorTypeInSandbox(editor)).toBe(false);
       });
 
@@ -533,25 +533,25 @@ describe('editor utils', () => {
 
     it('should return false for vscode when installed and in sandbox mode', () => {
       (execSync as Mock).mockReturnValue(Buffer.from('/usr/bin/code'));
-      process.env.SANDBOX = 'sandbox';
+      vi.stubEnv('SANDBOX', 'sandbox');
       expect(isEditorAvailable('vscode')).toBe(false);
     });
 
     it('should return true for vim when installed and in sandbox mode', () => {
       (execSync as Mock).mockReturnValue(Buffer.from('/usr/bin/vim'));
-      process.env.SANDBOX = 'sandbox';
+      vi.stubEnv('SANDBOX', 'sandbox');
       expect(isEditorAvailable('vim')).toBe(true);
     });
 
     it('should return true for emacs when installed and in sandbox mode', () => {
       (execSync as Mock).mockReturnValue(Buffer.from('/usr/bin/emacs'));
-      process.env.SANDBOX = 'sandbox';
+      vi.stubEnv('SANDBOX', 'sandbox');
       expect(isEditorAvailable('emacs')).toBe(true);
     });
 
     it('should return true for neovim when installed and in sandbox mode', () => {
       (execSync as Mock).mockReturnValue(Buffer.from('/usr/bin/nvim'));
-      process.env.SANDBOX = 'sandbox';
+      vi.stubEnv('SANDBOX', 'sandbox');
       expect(isEditorAvailable('neovim')).toBe(true);
     });
   });
diff --git a/packages/core/src/utils/editor.ts b/packages/core/src/utils/editor.ts
index f22297df..efaef249 100644
--- a/packages/core/src/utils/editor.ts
+++ b/packages/core/src/utils/editor.ts
@@ -72,7 +72,7 @@ export function checkHasEditorType(editor: EditorType): boolean {
 }
 
 export function allowEditorTypeInSandbox(editor: EditorType): boolean {
-  const notUsingSandbox = !process.env.SANDBOX;
+  const notUsingSandbox = !process.env['SANDBOX'];
   if (['vscode', 'vscodium', 'windsurf', 'cursor', 'zed'].includes(editor)) {
     return notUsingSandbox;
   }
diff --git a/packages/core/src/utils/memoryDiscovery.test.ts b/packages/core/src/utils/memoryDiscovery.test.ts
index 6c229dbb..d8f3ccc5 100644
--- a/packages/core/src/utils/memoryDiscovery.test.ts
+++ b/packages/core/src/utils/memoryDiscovery.test.ts
@@ -48,8 +48,8 @@ describe('loadServerHierarchicalMemory', () => {
 
     vi.resetAllMocks();
     // Set environment variables to indicate test environment
-    process.env.NODE_ENV = 'test';
-    process.env.VITEST = 'true';
+    vi.stubEnv('NODE_ENV', 'test');
+    vi.stubEnv('VITEST', 'true');
 
     projectRoot = await createEmptyDir(path.join(testRootDir, 'project'));
     cwd = await createEmptyDir(path.join(projectRoot, 'src'));
@@ -58,6 +58,7 @@ describe('loadServerHierarchicalMemory', () => {
   });
 
   afterEach(async () => {
+    vi.unstubAllEnvs();
     // Some tests set this to a different value.
     setGeminiMdFilename(DEFAULT_CONTEXT_FILENAME);
     // Clean up the temporary directory to prevent resource leaks.
diff --git a/packages/core/src/utils/memoryDiscovery.ts b/packages/core/src/utils/memoryDiscovery.ts
index fcb1abdd..d3c24baf 100644
--- a/packages/core/src/utils/memoryDiscovery.ts
+++ b/packages/core/src/utils/memoryDiscovery.ts
@@ -57,8 +57,9 @@ async function findProjectRoot(startDir: string): Promise<string | null> {
         (error as { code: string }).code === 'ENOENT';
 
       // Only log unexpected errors in non-test environments
-      // process.env.NODE_ENV === 'test' or VITEST are common test indicators
-      const isTestEnv = process.env.NODE_ENV === 'test' || process.env.VITEST;
+      // process.env['NODE_ENV'] === 'test' or VITEST are common test indicators
+      const isTestEnv =
+        process.env['NODE_ENV'] === 'test' || process.env['VITEST'];
 
       if (!isENOENT && !isTestEnv) {
         if (typeof error === 'object' && error !== null && 'code' in error) {
@@ -246,7 +247,8 @@ async function readGeminiMdFiles(
           `Successfully read and processed imports: ${filePath} (Length: ${processedResult.content.length})`,
         );
     } catch (error: unknown) {
-      const isTestEnv = process.env.NODE_ENV === 'test' || process.env.VITEST;
+      const isTestEnv =
+        process.env['NODE_ENV'] === 'test' || process.env['VITEST'];
       if (!isTestEnv) {
         const message = error instanceof Error ? error.message : String(error);
         logger.warn(
diff --git a/packages/core/src/utils/secure-browser-launcher.ts b/packages/core/src/utils/secure-browser-launcher.ts
index ec8357be..c60a646d 100644
--- a/packages/core/src/utils/secure-browser-launcher.ts
+++ b/packages/core/src/utils/secure-browser-launcher.ts
@@ -151,20 +151,23 @@ export function shouldLaunchBrowser(): boolean {
   // A list of browser names that indicate we should not attempt to open a
   // web browser for the user.
   const browserBlocklist = ['www-browser'];
-  const browserEnv = process.env.BROWSER;
+  const browserEnv = process.env['BROWSER'];
   if (browserEnv && browserBlocklist.includes(browserEnv)) {
     return false;
   }
 
   // Common environment variables used in CI/CD or other non-interactive shells.
-  if (process.env.CI || process.env.DEBIAN_FRONTEND === 'noninteractive') {
+  if (
+    process.env['CI'] ||
+    process.env['DEBIAN_FRONTEND'] === 'noninteractive'
+  ) {
     return false;
   }
 
   // The presence of SSH_CONNECTION indicates a remote session.
   // We should not attempt to launch a browser unless a display is explicitly available
   // (checked below for Linux).
-  const isSSH = !!process.env.SSH_CONNECTION;
+  const isSSH = !!process.env['SSH_CONNECTION'];
 
   // On Linux, the presence of a display server is a strong indicator of a GUI.
   if (platform() === 'linux') {
diff --git a/packages/core/src/utils/shell-utils.test.ts b/packages/core/src/utils/shell-utils.test.ts
index 913ec897..18f88e11 100644
--- a/packages/core/src/utils/shell-utils.test.ts
+++ b/packages/core/src/utils/shell-utils.test.ts
@@ -388,7 +388,7 @@ describe('getShellConfiguration', () => {
     });
 
     it('should return cmd.exe configuration by default', () => {
-      delete process.env.ComSpec;
+      delete process.env['ComSpec'];
       const config = getShellConfiguration();
       expect(config.executable).toBe('cmd.exe');
       expect(config.argsPrefix).toEqual(['/d', '/s', '/c']);
@@ -397,7 +397,7 @@ describe('getShellConfiguration', () => {
 
     it('should respect ComSpec for cmd.exe', () => {
       const cmdPath = 'C:\\WINDOWS\\system32\\cmd.exe';
-      process.env.ComSpec = cmdPath;
+      process.env['ComSpec'] = cmdPath;
       const config = getShellConfiguration();
       expect(config.executable).toBe(cmdPath);
       expect(config.argsPrefix).toEqual(['/d', '/s', '/c']);
@@ -407,7 +407,7 @@ describe('getShellConfiguration', () => {
     it('should return PowerShell configuration if ComSpec points to powershell.exe', () => {
       const psPath =
         'C:\\WINDOWS\\System32\\WindowsPowerShell\\v1.0\\powershell.exe';
-      process.env.ComSpec = psPath;
+      process.env['ComSpec'] = psPath;
       const config = getShellConfiguration();
       expect(config.executable).toBe(psPath);
       expect(config.argsPrefix).toEqual(['-NoProfile', '-Command']);
@@ -416,7 +416,7 @@ describe('getShellConfiguration', () => {
 
     it('should return PowerShell configuration if ComSpec points to pwsh.exe', () => {
       const pwshPath = 'C:\\Program Files\\PowerShell\\7\\pwsh.exe';
-      process.env.ComSpec = pwshPath;
+      process.env['ComSpec'] = pwshPath;
       const config = getShellConfiguration();
       expect(config.executable).toBe(pwshPath);
       expect(config.argsPrefix).toEqual(['-NoProfile', '-Command']);
@@ -424,7 +424,7 @@ describe('getShellConfiguration', () => {
     });
 
     it('should be case-insensitive when checking ComSpec', () => {
-      process.env.ComSpec = 'C:\\Path\\To\\POWERSHELL.EXE';
+      process.env['ComSpec'] = 'C:\\Path\\To\\POWERSHELL.EXE';
       const config = getShellConfiguration();
       expect(config.executable).toBe('C:\\Path\\To\\POWERSHELL.EXE');
       expect(config.argsPrefix).toEqual(['-NoProfile', '-Command']);
diff --git a/packages/core/src/utils/shell-utils.ts b/packages/core/src/utils/shell-utils.ts
index 2c818c8e..808cf893 100644
--- a/packages/core/src/utils/shell-utils.ts
+++ b/packages/core/src/utils/shell-utils.ts
@@ -37,7 +37,7 @@ export interface ShellConfiguration {
  */
 export function getShellConfiguration(): ShellConfiguration {
   if (isWindows()) {
-    const comSpec = process.env.ComSpec || 'cmd.exe';
+    const comSpec = process.env['ComSpec'] || 'cmd.exe';
     const executable = comSpec.toLowerCase();
 
     if (
diff --git a/packages/core/src/utils/systemEncoding.test.ts b/packages/core/src/utils/systemEncoding.test.ts
index 9375db9e..afabd33f 100644
--- a/packages/core/src/utils/systemEncoding.test.ts
+++ b/packages/core/src/utils/systemEncoding.test.ts
@@ -39,9 +39,9 @@ describe('Shell Command Processor - Encoding Functions', () => {
     resetEncodingCache();
 
     // Clear environment variables that might affect tests
-    delete process.env.LC_ALL;
-    delete process.env.LC_CTYPE;
-    delete process.env.LANG;
+    delete process.env['LC_ALL'];
+    delete process.env['LC_CTYPE'];
+    delete process.env['LANG'];
   });
 
   afterEach(() => {
@@ -218,21 +218,21 @@ describe('Shell Command Processor - Encoding Functions', () => {
     });
 
     it('should parse locale from LC_ALL environment variable', () => {
-      process.env.LC_ALL = 'en_US.UTF-8';
+      process.env['LC_ALL'] = 'en_US.UTF-8';
 
       const result = getSystemEncoding();
       expect(result).toBe('utf-8');
     });
 
     it('should parse locale from LC_CTYPE when LC_ALL is not set', () => {
-      process.env.LC_CTYPE = 'fr_FR.ISO-8859-1';
+      process.env['LC_CTYPE'] = 'fr_FR.ISO-8859-1';
 
       const result = getSystemEncoding();
       expect(result).toBe('iso-8859-1');
     });
 
     it('should parse locale from LANG when LC_ALL and LC_CTYPE are not set', () => {
-      process.env.LANG = 'de_DE.UTF-8';
+      process.env['LANG'] = 'de_DE.UTF-8';
 
       const result = getSystemEncoding();
       expect(result).toBe('utf-8');
@@ -268,16 +268,16 @@ describe('Shell Command Processor - Encoding Functions', () => {
     });
 
     it('should handle locale without encoding (no dot)', () => {
-      process.env.LANG = 'C';
+      process.env['LANG'] = 'C';
 
       const result = getSystemEncoding();
       expect(result).toBe('c');
     });
 
     it('should handle empty locale environment variables', () => {
-      process.env.LC_ALL = '';
-      process.env.LC_CTYPE = '';
-      process.env.LANG = '';
+      process.env['LC_ALL'] = '';
+      process.env['LC_CTYPE'] = '';
+      process.env['LANG'] = '';
       mockedExecSync.mockReturnValue('UTF-8');
 
       const result = getSystemEncoding();
@@ -285,24 +285,24 @@ describe('Shell Command Processor - Encoding Functions', () => {
     });
 
     it('should return locale as-is when locale format has no dot', () => {
-      process.env.LANG = 'invalid_format';
+      process.env['LANG'] = 'invalid_format';
 
       const result = getSystemEncoding();
       expect(result).toBe('invalid_format');
     });
 
     it('should prioritize LC_ALL over other environment variables', () => {
-      process.env.LC_ALL = 'en_US.UTF-8';
-      process.env.LC_CTYPE = 'fr_FR.ISO-8859-1';
-      process.env.LANG = 'de_DE.CP1252';
+      process.env['LC_ALL'] = 'en_US.UTF-8';
+      process.env['LC_CTYPE'] = 'fr_FR.ISO-8859-1';
+      process.env['LANG'] = 'de_DE.CP1252';
 
       const result = getSystemEncoding();
       expect(result).toBe('utf-8');
     });
 
     it('should prioritize LC_CTYPE over LANG', () => {
-      process.env.LC_CTYPE = 'fr_FR.ISO-8859-1';
-      process.env.LANG = 'de_DE.CP1252';
+      process.env['LC_CTYPE'] = 'fr_FR.ISO-8859-1';
+      process.env['LANG'] = 'de_DE.CP1252';
 
       const result = getSystemEncoding();
       expect(result).toBe('iso-8859-1');
@@ -315,7 +315,7 @@ describe('Shell Command Processor - Encoding Functions', () => {
     });
 
     it('should use cached system encoding on subsequent calls', () => {
-      process.env.LANG = 'en_US.UTF-8';
+      process.env['LANG'] = 'en_US.UTF-8';
       const buffer = Buffer.from('test');
 
       // First call
@@ -323,7 +323,7 @@ describe('Shell Command Processor - Encoding Functions', () => {
       expect(result1).toBe('utf-8');
 
       // Change environment (should not affect cached result)
-      process.env.LANG = 'fr_FR.ISO-8859-1';
+      process.env['LANG'] = 'fr_FR.ISO-8859-1';
 
       // Second call should use cached value
       const result2 = getCachedEncodingForBuffer(buffer);
@@ -435,7 +435,7 @@ describe('Shell Command Processor - Encoding Functions', () => {
   describe('Cross-platform behavior', () => {
     it('should work correctly on macOS', () => {
       mockedOsPlatform.mockReturnValue('darwin');
-      process.env.LANG = 'en_US.UTF-8';
+      process.env['LANG'] = 'en_US.UTF-8';
 
       const result = getSystemEncoding();
       expect(result).toBe('utf-8');
@@ -443,7 +443,7 @@ describe('Shell Command Processor - Encoding Functions', () => {
 
     it('should work correctly on other Unix-like systems', () => {
       mockedOsPlatform.mockReturnValue('freebsd');
-      process.env.LANG = 'en_US.UTF-8';
+      process.env['LANG'] = 'en_US.UTF-8';
 
       const result = getSystemEncoding();
       expect(result).toBe('utf-8');
@@ -451,7 +451,7 @@ describe('Shell Command Processor - Encoding Functions', () => {
 
     it('should handle unknown platforms as Unix-like', () => {
       mockedOsPlatform.mockReturnValue('unknown' as NodeJS.Platform);
-      process.env.LANG = 'en_US.UTF-8';
+      process.env['LANG'] = 'en_US.UTF-8';
 
       const result = getSystemEncoding();
       expect(result).toBe('utf-8');
@@ -461,7 +461,7 @@ describe('Shell Command Processor - Encoding Functions', () => {
   describe('Edge cases and error handling', () => {
     it('should handle empty buffer gracefully', () => {
       mockedOsPlatform.mockReturnValue('linux');
-      process.env.LANG = 'en_US.UTF-8';
+      process.env['LANG'] = 'en_US.UTF-8';
 
       const buffer = Buffer.alloc(0);
       const result = getCachedEncodingForBuffer(buffer);
@@ -470,7 +470,7 @@ describe('Shell Command Processor - Encoding Functions', () => {
 
     it('should handle very large buffers', () => {
       mockedOsPlatform.mockReturnValue('linux');
-      process.env.LANG = 'en_US.UTF-8';
+      process.env['LANG'] = 'en_US.UTF-8';
 
       const buffer = Buffer.alloc(1024 * 1024, 'a');
       const result = getCachedEncodingForBuffer(buffer);
diff --git a/packages/core/src/utils/systemEncoding.ts b/packages/core/src/utils/systemEncoding.ts
index f162c223..ba632d41 100644
--- a/packages/core/src/utils/systemEncoding.ts
+++ b/packages/core/src/utils/systemEncoding.ts
@@ -79,7 +79,7 @@ export function getSystemEncoding(): string | null {
   // system encoding. However, these environment variables might not always
   // be set or accurate. Handle cases where none of these variables are set.
   const env = process.env;
-  let locale = env.LC_ALL || env.LC_CTYPE || env.LANG || '';
+  let locale = env['LC_ALL'] || env['LC_CTYPE'] || env['LANG'] || '';
 
   // Fallback to querying the system directly when environment variables are missing
   if (!locale) {