diff --git a/plugin/core/config.ts b/plugin/core/config.ts
index 421ef5b..c8eada7 100644
--- a/plugin/core/config.ts
+++ b/plugin/core/config.ts
@@ -32,25 +32,25 @@ export function validateYonexusClientConfig(raw: unknown): YonexusClientConfig {
   const source = (raw && typeof raw === "object" ? raw : {}) as Record<string, unknown>;
   const issues: string[] = [];
 
-  const mainHost = source.mainHost;
-  if (!isNonEmptyString(mainHost)) {
+  const rawMainHost = source.mainHost;
+  if (!isNonEmptyString(rawMainHost)) {
     issues.push("mainHost is required");
-  } else if (!isValidWsUrl(mainHost.trim())) {
+  } else if (!isValidWsUrl(rawMainHost.trim())) {
     issues.push("mainHost must be a valid ws:// or wss:// URL");
   }
 
-  const identifier = source.identifier;
-  if (!isNonEmptyString(identifier)) {
+  const rawIdentifier = source.identifier;
+  if (!isNonEmptyString(rawIdentifier)) {
     issues.push("identifier is required");
   }
 
-  const notifyBotToken = source.notifyBotToken;
-  if (!isNonEmptyString(notifyBotToken)) {
+  const rawNotifyBotToken = source.notifyBotToken;
+  if (!isNonEmptyString(rawNotifyBotToken)) {
     issues.push("notifyBotToken is required");
   }
 
-  const adminUserId = source.adminUserId;
-  if (!isNonEmptyString(adminUserId)) {
+  const rawAdminUserId = source.adminUserId;
+  if (!isNonEmptyString(rawAdminUserId)) {
     issues.push("adminUserId is required");
   }
 
@@ -58,10 +58,15 @@ export function validateYonexusClientConfig(raw: unknown): YonexusClientConfig {
     throw new YonexusClientConfigError(issues);
   }
 
+  const mainHost = (rawMainHost as string).trim();
+  const identifier = (rawIdentifier as string).trim();
+  const notifyBotToken = (rawNotifyBotToken as string).trim();
+  const adminUserId = (rawAdminUserId as string).trim();
+
   return {
-    mainHost: mainHost.trim(),
-    identifier: identifier.trim(),
-    notifyBotToken: notifyBotToken.trim(),
-    adminUserId: adminUserId.trim()
+    mainHost,
+    identifier,
+    notifyBotToken,
+    adminUserId
   };
 }
diff --git a/plugin/core/state.ts b/plugin/core/state.ts
index f6a9b08..fc45866 100644
--- a/plugin/core/state.ts
+++ b/plugin/core/state.ts
@@ -181,7 +181,8 @@ function assertClientStateShape(
     );
   }
 
-  if (!Number.isInteger(candidate.updatedAt) || candidate.updatedAt < 0) {
+  const updatedAt = candidate.updatedAt;
+  if (typeof updatedAt !== "number" || !Number.isInteger(updatedAt) || updatedAt < 0) {
     throw new YonexusClientStateCorruptionError(
       `Client state file has invalid updatedAt value: ${filePath}`
     );
diff --git a/plugin/types/ws.d.ts b/plugin/types/ws.d.ts
new file mode 100644
index 0000000..d8b7f2f
--- /dev/null
+++ b/plugin/types/ws.d.ts
@@ -0,0 +1,24 @@
+declare module "ws" {
+  export type RawData = Buffer | ArrayBuffer | Buffer[] | string;
+
+  export class WebSocket {
+    static readonly OPEN: number;
+    constructor(url: string);
+    readonly readyState: number;
+    send(data: string): void;
+    close(code?: number, reason?: string): void;
+    terminate(): void;
+    on(event: "open", listener: () => void): this;
+    on(event: "message", listener: (data: RawData) => void): this;
+    on(event: "close", listener: (code: number, reason: Buffer) => void): this;
+    on(event: "error", listener: (error: Error) => void): this;
+    once(event: "open", listener: () => void): this;
+    once(event: "error", listener: (error: Error) => void): this;
+    off(event: "error", listener: (error: Error) => void): this;
+    removeAllListeners?(event?: string): this;
+  }
+
+  export class WebSocketServer {
+    constructor(options: { host?: string; port: number });
+  }
+}
diff --git a/tsconfig.json b/tsconfig.json
index cf17390..658f108 100644
--- a/tsconfig.json
+++ b/tsconfig.json
@@ -4,7 +4,7 @@
     "module": "NodeNext",
     "moduleResolution": "NodeNext",
     "outDir": "dist",
-    "rootDir": ".",
+    "rootDir": "..",
     "strict": true,
     "skipLibCheck": true,
     "esModuleInterop": true,
@@ -15,7 +15,9 @@
   },
   "include": [
     "plugin/**/*.ts",
-    "servers/**/*.ts"
+    "plugin/**/*.d.ts",
+    "servers/**/*.ts",
+    "../Yonexus.Protocol/src/**/*.ts"
   ],
   "exclude": [
     "dist",