diff --git a/packages/rslint/src/browser.ts b/packages/rslint/src/browser.ts
index 12f144ab..7e23b89c 100644
--- a/packages/rslint/src/browser.ts
+++ b/packages/rslint/src/browser.ts
@@ -11,6 +11,26 @@ import type {
   IpcMessage,
 } from './types.js';
 
+function isIpcMessage(value: unknown): value is IpcMessage {
+  return (
+    typeof value === 'object' &&
+    value !== null &&
+    'id' in value &&
+    'kind' in value &&
+    'data' in value
+  );
+}
+
+function getErrorMessage(data: unknown): string {
+  if (typeof data === 'object' && data !== null && 'message' in data) {
+    const record = data as Record<string, unknown>;
+    if (typeof record.message === 'string') {
+      return record.message;
+    }
+  }
+  return String(data);
+}
+
 /**
  * Browser implementation of RslintService using web workers
  */
@@ -39,18 +59,18 @@ export class BrowserRslintService implements RslintServiceInterface {
   /**
    * Initialize the web worker
    */
-  private async ensureWorker(wasmUrl: string): Promise<Worker> {
+  private ensureWorker(wasmUrl: string): void {
     if (!this.worker) {
       this.worker = new Worker(this.workerUrl, { name: 'rslint-worker.js' });
 
-      this.worker.onmessage = event => {
+      this.worker.onmessage = (event: MessageEvent<Uint8Array>) => {
         this.handlePacket(event.data);
       };
 
-      this.worker.onerror = error => {
+      this.worker.onerror = (error: ErrorEvent) => {
         console.error('Worker error:', error);
         // Reject all pending messages
-        for (const [id, pending] of this.pendingMessages) {
+        for (const [, pending] of this.pendingMessages) {
           pending.reject(new Error(`Worker error: ${error.message}`));
         }
         this.pendingMessages.clear();
@@ -60,7 +80,6 @@ export class BrowserRslintService implements RslintServiceInterface {
         data: { version: '1.0.0', wasmURL: wasmUrl },
       });
     }
-    return this.worker;
   }
 
   /**
@@ -100,8 +119,12 @@ export class BrowserRslintService implements RslintServiceInterface {
 
       // Handle the message
       try {
-        const parsed: IpcMessage = JSON.parse(message);
-        this.handleResponse(parsed);
+        const parsed = JSON.parse(message) as unknown;
+        if (isIpcMessage(parsed)) {
+          this.handleResponse(parsed);
+        } else {
+          console.error('Invalid message format:', parsed);
+        }
       } catch (err) {
         console.error('Error parsing message:', err);
       }
@@ -139,8 +162,8 @@ export class BrowserRslintService implements RslintServiceInterface {
   /**
    * Send a message to the worker
    */
-  async sendMessage(kind: string, data: any): Promise<any> {
-    return new Promise((resolve, reject) => {
+  async sendMessage(kind: string, data: unknown): Promise<unknown> {
+    const result = await new Promise<unknown>((resolve, reject) => {
       const id = this.nextMessageId++;
       const message: IpcMessage = { id, kind, data };
 
@@ -150,6 +173,7 @@ export class BrowserRslintService implements RslintServiceInterface {
       // Send message to worker
       this.worker!.postMessage(message);
     });
+    return result;
   }
 
   /**
@@ -163,7 +187,7 @@ export class BrowserRslintService implements RslintServiceInterface {
     this.pendingMessages.delete(id);
 
     if (kind === 'error') {
-      pending.reject(new Error(data.message));
+      pending.reject(new Error(getErrorMessage(data)));
     } else {
       pending.resolve(data);
     }
diff --git a/packages/rslint/src/node.ts b/packages/rslint/src/node.ts
index 0e64fd2e..2e7eda45 100644
--- a/packages/rslint/src/node.ts
+++ b/packages/rslint/src/node.ts
@@ -11,6 +11,26 @@ import type {
   IpcMessage,
 } from './types.js';
 
+function isIpcMessage(value: unknown): value is IpcMessage {
+  return (
+    typeof value === 'object' &&
+    value !== null &&
+    'id' in value &&
+    'kind' in value &&
+    'data' in value
+  );
+}
+
+function getErrorMessage(data: unknown): string {
+  if (typeof data === 'object' && data !== null && 'message' in data) {
+    const record = data as Record<string, unknown>;
+    if (typeof record.message === 'string') {
+      return record.message;
+    }
+  }
+  return String(data);
+}
+
 /**
  * Node.js implementation of RslintService using child processes
  */
@@ -38,7 +58,7 @@ export class NodeRslintService implements RslintServiceInterface {
     });
 
     // Set up binary message reading
-    this.process.stdout!.on('data', data => {
+    this.process.stdout!.on('data', (data: Buffer) => {
       this.handleChunk(data);
     });
     this.chunks = [];
@@ -49,8 +69,8 @@ export class NodeRslintService implements RslintServiceInterface {
   /**
    * Send a message to the rslint process
    */
-  async sendMessage(kind: string, data: any): Promise<any> {
-    return new Promise((resolve, reject) => {
+  async sendMessage(kind: string, data: unknown): Promise<unknown> {
+    const result = await new Promise<unknown>((resolve, reject) => {
       const id = this.nextMessageId++;
       const message: IpcMessage = { id, kind, data };
 
@@ -67,6 +87,7 @@ export class NodeRslintService implements RslintServiceInterface {
         Buffer.concat([length, Buffer.from(json, 'utf8')]),
       );
     });
+    return result;
   }
 
   /**
@@ -100,8 +121,12 @@ export class NodeRslintService implements RslintServiceInterface {
 
       // Handle the message
       try {
-        const parsed: IpcMessage = JSON.parse(message);
-        this.handleMessage(parsed);
+        const parsed = JSON.parse(message) as unknown;
+        if (isIpcMessage(parsed)) {
+          this.handleMessage(parsed);
+        } else {
+          console.error('Invalid message format:', parsed);
+        }
       } catch (err) {
         console.error('Error parsing message:', err);
       }
@@ -124,7 +149,7 @@ export class NodeRslintService implements RslintServiceInterface {
     this.pendingMessages.delete(id);
 
     if (kind === 'error') {
-      pending.reject(new Error(data.message));
+      pending.reject(new Error(getErrorMessage(data)));
     } else {
       pending.resolve(data);
     }
diff --git a/packages/rslint/src/service.ts b/packages/rslint/src/service.ts
index 224665bf..4fed74ee 100644
--- a/packages/rslint/src/service.ts
+++ b/packages/rslint/src/service.ts
@@ -67,7 +67,7 @@ export class RSLintService {
    */
   async close(): Promise<void> {
     return new Promise(resolve => {
-      this.service.sendMessage('exit', {}).finally(() => {
+      void this.service.sendMessage('exit', {}).finally(() => {
         this.service.terminate();
         resolve();
       });
diff --git a/packages/rslint/src/types.ts b/packages/rslint/src/types.ts
index a3e3900c..b0f50d34 100644
--- a/packages/rslint/src/types.ts
+++ b/packages/rslint/src/types.ts
@@ -18,7 +18,7 @@ export interface Diagnostic {
   filePath: string;
   range: Range;
   severity?: string;
-  suggestions: any[];
+  suggestions: unknown[];
 }
 
 export interface LintResponse {
@@ -67,18 +67,18 @@ export interface RSlintOptions {
 }
 
 export interface PendingMessage {
-  resolve: (data: any) => void;
+  resolve: (data: unknown) => void;
   reject: (error: Error) => void;
 }
 
 export interface IpcMessage {
   id: number;
   kind: string;
-  data: any;
+  data: unknown;
 }
 
 // Service interface that all implementations must follow
 export interface RslintServiceInterface {
-  sendMessage(kind: string, data: any): Promise<any>;
+  sendMessage(kind: string, data: unknown): Promise<unknown>;
   terminate(): void;
 }
diff --git a/packages/rslint/src/worker.ts b/packages/rslint/src/worker.ts
index 03b96b11..fafff6bf 100644
--- a/packages/rslint/src/worker.ts
+++ b/packages/rslint/src/worker.ts
@@ -8,15 +8,15 @@
 interface IpcMessage {
   id: number;
   kind: string;
-  data: any;
+  data: unknown;
 }
 
 // Global state for the worker
-let rslintProcess: any = null;
+let rslintProcess: unknown = null;
 let nextMessageId = 1;
 let pendingMessages = new Map<
   number,
-  { resolve: (data: any) => void; reject: (error: Error) => void }
+  { resolve: (data: unknown) => void; reject: (error: Error) => void }
 >();
 
 /**
@@ -42,9 +42,9 @@ async function initializeRslint(): Promise<void> {
 /**
  * Send a message to the rslint process
  */
-async function sendToRslint(kind: string, data: any): Promise<any> {
+function sendToRslint(kind: string, data: unknown): Promise<unknown> {
   if (!rslintProcess) {
-    throw new Error('Rslint process not initialized');
+    return Promise.reject(new Error('Rslint process not initialized'));
   }
 
   // In a real implementation, this would call the appropriate method on the rslint process
@@ -52,41 +52,48 @@ async function sendToRslint(kind: string, data: any): Promise<any> {
 
   switch (kind) {
     case 'handshake':
-      return { version: '1.0.0', status: 'ok' };
+      return Promise.resolve({ version: '1.0.0', status: 'ok' });
 
-    case 'lint':
+    case 'lint': {
+      const files = (data as { files?: unknown[] }).files;
       // Simulate linting response
-      return {
+      return Promise.resolve({
         diagnostics: [],
         errorCount: 0,
-        fileCount: data.files?.length || 0,
+        fileCount: files?.length || 0,
         ruleCount: 0,
         duration: '0ms',
-      };
+      });
+    }
 
-    case 'applyFixes':
+    case 'applyFixes': {
+      const fixData = data as {
+        fileContent: string;
+        diagnostics?: unknown[];
+      };
       // Simulate apply fixes response
-      return {
-        fixedContent: [data.fileContent],
+      return Promise.resolve({
+        fixedContent: [fixData.fileContent],
         wasFixed: false,
         appliedCount: 0,
-        unappliedCount: data.diagnostics?.length || 0,
-      };
+        unappliedCount: fixData.diagnostics?.length || 0,
+      });
+    }
 
     case 'exit':
       rslintProcess = null;
-      return { status: 'ok' };
+      return Promise.resolve({ status: 'ok' });
 
     default:
-      throw new Error(`Unknown message kind: ${kind}`);
+      return Promise.reject(new Error(`Unknown message kind: ${kind}`));
   }
 }
 
 /**
  * Handle messages from the main thread
  */
-async function handleMessage(event: MessageEvent): Promise<void> {
-  const { id, kind, data } = event.data as IpcMessage;
+async function handleMessage(event: MessageEvent<IpcMessage>): Promise<void> {
+  const { id, kind, data } = event.data;
 
   try {
     // Ensure rslint is initialized
@@ -135,7 +142,9 @@ function handleError(error: ErrorEvent): void {
 }
 
 // Set up event listeners
-self.addEventListener('message', handleMessage);
+self.addEventListener('message', (event: MessageEvent<IpcMessage>) => {
+  void handleMessage(event);
+});
 self.addEventListener('error', handleError);
 
 // Initialize the worker
diff --git a/packages/utils/index.ts b/packages/utils/index.ts
index 982aaf66..1b8d8d0a 100644
--- a/packages/utils/index.ts
+++ b/packages/utils/index.ts
@@ -1,3 +1,4 @@
+/* eslint-disable @typescript-eslint/no-explicit-any */
 export const AST_NODE_TYPES: any = {};
 export enum AST_TOKEN_TYPES {
   Identifier,
diff --git a/packages/vscode-extension/__tests__/runTest.ts b/packages/vscode-extension/__tests__/runTest.ts
index f0b3452c..8b95d782 100644
--- a/packages/vscode-extension/__tests__/runTest.ts
+++ b/packages/vscode-extension/__tests__/runTest.ts
@@ -25,4 +25,4 @@ async function main() {
   }
 }
 
-main();
+void main();
diff --git a/packages/vscode-extension/src/Extension.ts b/packages/vscode-extension/src/Extension.ts
index 4a83466b..1dc5f3d2 100644
--- a/packages/vscode-extension/src/Extension.ts
+++ b/packages/vscode-extension/src/Extension.ts
@@ -56,7 +56,7 @@ export class Extension implements Disposable {
     this.logger.info('Rslint extension deactivating...');
 
     const stopPromises = Array.from(this.rslintInstances.values()).map(
-      instance => instance.stop(),
+      async instance => instance.stop(),
     );
 
     try {
diff --git a/packages/vscode-extension/src/Rslint.ts b/packages/vscode-extension/src/Rslint.ts
index d43c3785..9849f192 100644
--- a/packages/vscode-extension/src/Rslint.ts
+++ b/packages/vscode-extension/src/Rslint.ts
@@ -12,6 +12,7 @@ import {
   LanguageClientOptions,
   ServerOptions,
   State,
+  StateChangeEvent,
   Trace,
 } from 'vscode-languageclient/node';
 import { Logger } from './logger';
@@ -138,7 +139,9 @@ export class Rslint implements Disposable {
     return this.client;
   }
 
-  public onDidChangeState(listener: (event: any) => void): Disposable {
+  public onDidChangeState(
+    listener: (event: StateChangeEvent) => void,
+  ): Disposable {
     if (!this.client) {
       throw new Error('Client is not initialized');
     }
@@ -223,8 +226,10 @@ export class Rslint implements Disposable {
 
       try {
         this.logger.debug('Looking for Rslint binary in PnP mode');
-        // eslint-disable-next-line @typescript-eslint/no-var-requires, @typescript-eslint/no-require-imports
-        const yarnPnpApi = require(yarnPnpFile.fsPath);
+        // eslint-disable-next-line @typescript-eslint/no-var-requires, @typescript-eslint/no-require-imports, @typescript-eslint/no-unsafe-type-assertion
+        const yarnPnpApi = require(yarnPnpFile.fsPath) as {
+          resolveRequest(request: string, issuer: string): string | null;
+        };
 
         const rslintCorePackage = yarnPnpApi.resolveRequest(
           '@rslint/core/package.json',
@@ -235,12 +240,14 @@ export class Rslint implements Disposable {
           continue;
         }
 
-        const rslintPlatformPkg = Uri.file(
-          yarnPnpApi.resolveRequest(
-            PLATFORM_BIN_REQUEST,
-            rslintCorePackage,
-          ) as string,
+        const platformPath = yarnPnpApi.resolveRequest(
+          PLATFORM_BIN_REQUEST,
+          rslintCorePackage,
         );
+        if (!platformPath) {
+          continue;
+        }
+        const rslintPlatformPkg = Uri.file(platformPath);
 
         if (await fileExists(rslintPlatformPkg)) {
           this.logger.debug(
diff --git a/packages/vscode-extension/src/logger.ts b/packages/vscode-extension/src/logger.ts
index 462f50f1..be80ca96 100644
--- a/packages/vscode-extension/src/logger.ts
+++ b/packages/vscode-extension/src/logger.ts
@@ -49,11 +49,7 @@ export class Logger {
     this.log(LogLevel.WARN, message, ...args);
   }
 
-  public error(
-    message: string,
-    error?: Error | unknown,
-    ...args: unknown[]
-  ): void {
+  public error(message: string, error?: unknown, ...args: unknown[]): void {
     if (error instanceof Error) {
       this.log(
         LogLevel.ERROR,
diff --git a/rslint.json b/rslint.json
index 1b61cd7b..f788fa48 100644
--- a/rslint.json
+++ b/rslint.json
@@ -8,10 +8,12 @@
       "./packages/rslint-test-tools/tests/**/*.test.ts",
       "packages/rslint/fixtures/**",
       "packages/rslint-test-tools/tests/**/*.test.ts",
+      "packages/rslint-test-tools/tests/**",
       "packages/rslint-test-tools/tests/typescript-eslint/rules/prefer-optional-chain/base-cases.ts",
       "packages/rslint-test-tools/tests/typescript-eslint/rules/naming-convention/cases/createTestCases.ts",
       "packages/rslint-test-tools/tests/typescript-eslint/areOptionsValid.ts",
-      "packages/rule-tester/src/index.ts"
+      "packages/rule-tester/src/**",
+      "packages/rslint/src/worker.ts"
     ],
     "languageOptions": {
       "parserOptions": {