diff --git a/src/components/ChatMessage.tsx b/src/components/ChatMessage.tsx
index 291bcab..41a4dfd 100644
--- a/src/components/ChatMessage.tsx
+++ b/src/components/ChatMessage.tsx
@@ -148,7 +148,7 @@ function renderTextBlocks(blocks: MessageBlock[]) {
   return getTextBlocks(blocks).map((block, i) => (
     <div key={`text-${i}`} className="markdown-body">
       <ReactMarkdown remarkPlugins={[remarkGfm, remarkBreaks]} rehypePlugins={[rehypeHighlight]} components={markdownComponents}>
-        {autoFormatText((block as any).text)}
+        {autoFormatText((block as Extract<MessageBlock, { type: 'text' }>).text)}
       </ReactMarkdown>
     </div>
   ));
@@ -238,7 +238,7 @@ function CopyButton({ text }: { text: string }) {
 /** Extract plain text from message blocks for clipboard copy */
 function getPlainText(message: ChatMessageType): string {
   if (message.blocks.length > 0) {
-    return getTextBlocks(message.blocks).map(b => (b as any).text).join('\n\n');
+    return getTextBlocks(message.blocks).map(b => (b as Extract<MessageBlock, { type: 'text' }>).text).join('\n\n');
   }
   return message.content;
 }
diff --git a/src/components/CodeBlock.tsx b/src/components/CodeBlock.tsx
index 9b7aca4..6b4c6e3 100644
--- a/src/components/CodeBlock.tsx
+++ b/src/components/CodeBlock.tsx
@@ -10,7 +10,7 @@ export function CodeBlock(props: HTMLAttributes<HTMLPreElement>) {
 
   const handleCopy = useCallback(() => {
     // Extract text from the nested <code> element
-    const code = (props.children as any)?.props?.children;
+    const code = (props.children as React.ReactElement<{ children?: string }> | undefined)?.props?.children;
     if (typeof code === 'string') {
       navigator.clipboard.writeText(code).then(() => {
         setCopied(true);
diff --git a/src/components/ToolCall.tsx b/src/components/ToolCall.tsx
index acd4739..7af9c7e 100644
--- a/src/components/ToolCall.tsx
+++ b/src/components/ToolCall.tsx
@@ -122,33 +122,40 @@ export function HighlightedPre({ text, className }: { text: string; className: s
   return <pre className={className}>{text}</pre>;
 }
 
-function getContextHint(name: string, input: any): string | null {
+function str(v: unknown): string | null {
+  return typeof v === 'string' ? v : null;
+}
+
+function getContextHint(name: string, input: Record<string, unknown> | undefined): string | null {
   if (!input || typeof input !== 'object') return null;
   switch (name) {
     case 'exec':
-      return input.command ? truncate(input.command, 60) : null;
+      return str(input.command) ? truncate(str(input.command)!, 60) : null;
     case 'Read': case 'read':
     case 'Write': case 'write':
     case 'Edit': case 'edit':
-      return input.file_path || input.path || null;
+      return str(input.file_path) || str(input.path) || null;
     case 'web_search':
-      return input.query ? truncate(input.query, 50) : null;
+      return str(input.query) ? truncate(str(input.query)!, 50) : null;
     case 'web_fetch':
-      return input.url ? truncate(input.url, 60) : null;
+      return str(input.url) ? truncate(str(input.url)!, 60) : null;
     case 'browser':
-      return input.action || null;
-    case 'message':
-      return input.action ? `${input.action}${input.target ? ' → ' + input.target : ''}` : null;
+      return str(input.action) || null;
+    case 'message': {
+      const action = str(input.action);
+      const target = str(input.target);
+      return action ? `${action}${target ? ' → ' + target : ''}` : null;
+    }
     case 'memory_search':
-      return input.query ? truncate(input.query, 50) : null;
+      return str(input.query) ? truncate(str(input.query)!, 50) : null;
     case 'memory_get':
-      return input.path || null;
+      return str(input.path) || null;
     case 'cron':
-      return input.action || null;
+      return str(input.action) || null;
     case 'sessions_spawn':
-      return input.task ? truncate(input.task, 50) : null;
+      return str(input.task) ? truncate(str(input.task)!, 50) : null;
     case 'image':
-      return input.prompt ? truncate(input.prompt, 50) : null;
+      return str(input.prompt) ? truncate(str(input.prompt)!, 50) : null;
     default:
       return null;
   }
@@ -184,7 +191,7 @@ function extractImageFromResult(result: string): { src: string; remaining: strin
   return null;
 }
 
-export function ToolCall({ name, input, result }: { name: string; input?: any; result?: string }) {
+export function ToolCall({ name, input, result }: { name: string; input?: Record<string, unknown>; result?: string }) {
   const t = useT();
   const [open, setOpen] = useState(false);
   const c = getColor(name);
diff --git a/src/hooks/useGateway.ts b/src/hooks/useGateway.ts
index 9847a1b..c6a5753 100644
--- a/src/hooks/useGateway.ts
+++ b/src/hooks/useGateway.ts
@@ -1,17 +1,21 @@
 import { useState, useEffect, useRef, useCallback } from 'react';
-import { GatewayClient } from '../lib/gateway';
+import { GatewayClient, type JsonPayload } from '../lib/gateway';
 import { genIdempotencyKey } from '../lib/utils';
 import { getStoredCredentials, storeCredentials, clearCredentials } from '../components/LoginScreen';
 import type { ChatMessage, MessageBlock, ConnectionStatus, Session } from '../types';
 
-function extractText(message: any): string {
+interface ChatPayloadMessage {
+  content?: string | Array<{ type: string; text?: string }>;
+}
+
+function extractText(message: ChatPayloadMessage | undefined): string {
   if (!message) return '';
   const content = message.content;
   if (typeof content === 'string') return content;
   if (Array.isArray(content)) {
     return content
-      .filter((b: any) => b.type === 'text' && typeof b.text === 'string')
-      .map((b: any) => b.text)
+      .filter((b) => b.type === 'text' && typeof b.text === 'string')
+      .map((b) => b.text as string)
       .join('\n');
   }
   return '';
@@ -72,7 +76,11 @@ export function useGateway() {
       }
       if (event !== 'chat') return;
 
-      const { state, runId, message, errorMessage, sessionKey: evtSession } = payload;
+      const state = payload.state as string | undefined;
+      const runId = payload.runId as string;
+      const message = payload.message as ChatPayloadMessage | undefined;
+      const errorMessage = payload.errorMessage as string | undefined;
+      const evtSession = payload.sessionKey as string | undefined;
 
       if (evtSession) {
         if (state === 'delta') {
@@ -167,12 +175,12 @@ export function useGateway() {
     }
   }, [setupClient]);
 
-  const handleAgentEvent = useCallback((payload: any) => {
+  const handleAgentEvent = useCallback((payload: JsonPayload) => {
     if (payload?.stream !== 'tool') return;
-    const data = payload.data ?? {};
-    const phase = data.phase;
-    const toolCallId = data.toolCallId;
-    const name = data.name || 'tool';
+    const data = (payload.data ?? {}) as Record<string, unknown>;
+    const phase = data.phase as string | undefined;
+    const toolCallId = data.toolCallId as string | undefined;
+    const name = (data.name as string) || 'tool';
     if (!toolCallId) return;
 
     setMessages(prev => {
@@ -185,11 +193,12 @@ export function useGateway() {
         updated.blocks.push({
           type: 'tool_use' as const,
           name,
-          input: data.args,
+          input: (data.args as Record<string, unknown>) ?? {},
           id: toolCallId,
         });
       } else if (phase === 'result') {
-        const result = typeof data.result === 'string' ? data.result : JSON.stringify(data.result, null, 2);
+        const rawResult = data.result;
+        const result = typeof rawResult === 'string' ? rawResult : JSON.stringify(rawResult, null, 2);
         updated.blocks.push({
           type: 'tool_result' as const,
           content: result?.slice(0, 500) || '',
@@ -205,15 +214,16 @@ export function useGateway() {
   const loadSessions = useCallback(async () => {
     try {
       const res = await clientRef.current?.send('sessions.list', {});
-      if (res?.sessions) {
-        setSessions(res.sessions.map((s: any) => ({
-          key: s.key || s.sessionKey,
-          label: s.label || s.key || s.sessionKey,
-          messageCount: s.messageCount,
-          totalTokens: s.totalTokens,
-          contextTokens: s.contextTokens,
-          inputTokens: s.inputTokens,
-          outputTokens: s.outputTokens,
+      const sessionList = res?.sessions as Array<Record<string, unknown>> | undefined;
+      if (sessionList) {
+        setSessions(sessionList.map((s) => ({
+          key: (s.key || s.sessionKey) as string,
+          label: (s.label || s.key || s.sessionKey) as string,
+          messageCount: s.messageCount as number | undefined,
+          totalTokens: s.totalTokens as number | undefined,
+          contextTokens: s.contextTokens as number | undefined,
+          inputTokens: s.inputTokens as number | undefined,
+          outputTokens: s.outputTokens as number | undefined,
         })));
       }
     } catch {}
@@ -222,9 +232,10 @@ export function useGateway() {
   const loadHistory = useCallback(async (sessionKey: string) => {
     try {
       const res = await clientRef.current?.send('chat.history', { sessionKey, limit: 100 });
-      if (res?.messages) {
-        const rawMsgs: any[] = res.messages;
-        const msgs: ChatMessage[] = rawMsgs.map((m: any, i: number) => {
+      const rawMsgs = res?.messages as Array<Record<string, unknown>> | undefined;
+      if (rawMsgs) {
+        /* eslint-disable @typescript-eslint/no-explicit-any -- raw gateway history messages have dynamic shape */
+        const msgs: ChatMessage[] = rawMsgs.map((m: Record<string, any>, i: number) => {
           const blocks: MessageBlock[] = [];
           if (m.content) {
             if (Array.isArray(m.content)) {
@@ -269,19 +280,20 @@ export function useGateway() {
           return {
             id: m.id || `hist-${i}`,
             role,
-            content: blocks.filter(b => b.type === 'text').map(b => (b as any).text).join(''),
+            content: blocks.filter((b): b is Extract<MessageBlock, { type: 'text' }> => b.type === 'text').map(b => b.text).join(''),
             timestamp: m.timestamp || Date.now(),
             blocks,
           };
         });
         const merged: ChatMessage[] = [];
         for (const msg of msgs) {
-          if ((msg as any).isToolResult && merged.length > 0 && merged[merged.length - 1].role === 'assistant') {
+          const isToolResult = 'isToolResult' in msg && (msg as ChatMessage & { isToolResult?: boolean }).isToolResult;
+          if (isToolResult && merged.length > 0 && merged[merged.length - 1].role === 'assistant') {
             merged[merged.length - 1] = {
               ...merged[merged.length - 1],
               blocks: [...merged[merged.length - 1].blocks, ...msg.blocks],
             };
-          } else if ((msg as any).isToolResult) {
+          } else if (isToolResult) {
             // skip orphan
           } else {
             merged.push(msg);
diff --git a/src/lib/gateway.ts b/src/lib/gateway.ts
index a152c27..2f6d001 100644
--- a/src/lib/gateway.ts
+++ b/src/lib/gateway.ts
@@ -1,14 +1,29 @@
 import { genId } from './utils';
 
-export type GatewayEventHandler = (event: string, payload: any) => void;
-export type GatewayResponseHandler = (id: string, ok: boolean, payload: any) => void;
+/** JSON-safe payload type used for gateway messages. */
+export type JsonPayload = Record<string, unknown>;
+
+export type GatewayEventHandler = (event: string, payload: JsonPayload) => void;
+export type GatewayResponseHandler = (id: string, ok: boolean, payload: JsonPayload) => void;
+
+/** Shape of an incoming WebSocket message from the gateway. */
+interface GatewayMessage {
+  type: 'event' | 'res';
+  // event fields
+  event?: string;
+  payload?: JsonPayload;
+  // response fields
+  id?: string;
+  ok?: boolean;
+  error?: string;
+}
 
 export class GatewayClient {
   private ws: WebSocket | null = null;
-  private pendingRequests = new Map<string, { resolve: (v: any) => void; reject: (e: any) => void }>();
+  private pendingRequests = new Map<string, { resolve: (v: JsonPayload) => void; reject: (e: unknown) => void }>();
   private eventHandlers: GatewayEventHandler[] = [];
   private _onStatus: (s: 'disconnected' | 'connecting' | 'connected') => void = () => {};
-  private reconnectTimer: any = null;
+  private reconnectTimer: ReturnType<typeof setTimeout> | null = null;
   private connected = false;
   private autoReconnect = true;
 
@@ -44,22 +59,22 @@ export class GatewayClient {
     this.ws.onopen = () => { console.log('[GW] WS open'); };
 
     this.ws.onmessage = (ev) => {
-      let msg: any;
-      try { msg = JSON.parse(ev.data); } catch { console.log('[GW] parse error', ev.data); return; }
+      let msg: GatewayMessage;
+      try { msg = JSON.parse(ev.data as string) as GatewayMessage; } catch { console.log('[GW] parse error', ev.data); return; }
       console.log('[GW] msg:', msg.type, msg.event || msg.id || '', msg.ok);
 
       if (msg.type === 'event') {
         if (msg.event === 'connect.challenge') {
           this.handleChallenge();
         } else {
-          for (const h of this.eventHandlers) h(msg.event, msg.payload);
+          for (const h of this.eventHandlers) h(msg.event ?? '', msg.payload ?? {});
         }
-      } else if (msg.type === 'res') {
+      } else if (msg.type === 'res' && msg.id) {
         const pending = this.pendingRequests.get(msg.id);
         if (pending) {
           this.pendingRequests.delete(msg.id);
-          if (msg.ok) pending.resolve(msg.payload);
-          else pending.reject(msg.payload || msg.error);
+          if (msg.ok) pending.resolve(msg.payload ?? {});
+          else pending.reject(msg.payload ?? msg.error ?? 'unknown error');
         }
       }
     };
@@ -118,7 +133,7 @@ export class GatewayClient {
     this._onStatus('disconnected');
   }
 
-  request(id: string, method: string, params: any): Promise<any> {
+  request(id: string, method: string, params: JsonPayload): Promise<JsonPayload> {
     return new Promise((resolve, reject) => {
       if (!this.ws || this.ws.readyState !== WebSocket.OPEN) {
         return reject(new Error('not connected'));
@@ -134,7 +149,7 @@ export class GatewayClient {
     });
   }
 
-  async send(method: string, params: any): Promise<any> {
+  async send(method: string, params: JsonPayload): Promise<JsonPayload> {
     const id = genId('req');
     return this.request(id, method, params);
   }
diff --git a/src/types/index.ts b/src/types/index.ts
index b97a9f1..dcf4400 100644
--- a/src/types/index.ts
+++ b/src/types/index.ts
@@ -11,7 +11,7 @@ export interface ChatMessage {
 export type MessageBlock =
   | { type: 'text'; text: string }
   | { type: 'thinking'; text: string }
-  | { type: 'tool_use'; name: string; input: any; id?: string }
+  | { type: 'tool_use'; name: string; input: Record<string, unknown>; id?: string }
   | { type: 'tool_result'; content: string; toolUseId?: string; name?: string }
   | { type: 'image'; mediaType: string; data?: string; url?: string };