diff --git a/packages/cli/src/nonInteractiveCli.test.ts b/packages/cli/src/nonInteractiveCli.test.ts
index 389d35f2..c071dedc 100644
--- a/packages/cli/src/nonInteractiveCli.test.ts
+++ b/packages/cli/src/nonInteractiveCli.test.ts
@@ -39,7 +39,7 @@ describe('runNonInteractive', () => {
       sendMessageStream: vi.fn(),
     };
     mockGeminiClient = {
-      startChat: vi.fn().mockResolvedValue(mockChat),
+      getChat: vi.fn().mockResolvedValue(mockChat),
     } as unknown as GeminiClient;
     mockToolRegistry = {
       getFunctionDeclarations: vi.fn().mockReturnValue([]),
@@ -80,7 +80,6 @@ describe('runNonInteractive', () => {
 
     await runNonInteractive(mockConfig, 'Test input');
 
-    expect(mockGeminiClient.startChat).toHaveBeenCalled();
     expect(mockChat.sendMessageStream).toHaveBeenCalledWith({
       message: [{ text: 'Test input' }],
       config: {
diff --git a/packages/cli/src/nonInteractiveCli.ts b/packages/cli/src/nonInteractiveCli.ts
index f7b4108b..7505c736 100644
--- a/packages/cli/src/nonInteractiveCli.ts
+++ b/packages/cli/src/nonInteractiveCli.ts
@@ -42,7 +42,7 @@ export async function runNonInteractive(
   const geminiClient = new GeminiClient(config);
   const toolRegistry: ToolRegistry = await config.getToolRegistry();
 
-  const chat = await geminiClient.startChat();
+  const chat = await geminiClient.getChat();
   const abortController = new AbortController();
   let currentMessages: Content[] = [{ role: 'user', parts: [{ text: input }] }];
 
diff --git a/packages/cli/src/ui/hooks/useGeminiStream.test.tsx b/packages/cli/src/ui/hooks/useGeminiStream.test.tsx
index 3a421ebf..d46fab9e 100644
--- a/packages/cli/src/ui/hooks/useGeminiStream.test.tsx
+++ b/packages/cli/src/ui/hooks/useGeminiStream.test.tsx
@@ -405,10 +405,9 @@ describe('useGeminiStream', () => {
       } as TrackedCancelledToolCall,
     ];
 
-    let hookResult: any;
-    await act(async () => {
-      hookResult = renderTestHook(simplifiedToolCalls);
-    });
+    const hookResult = await act(async () =>
+      renderTestHook(simplifiedToolCalls),
+    );
 
     const {
       mockMarkToolsAsSubmitted,
@@ -431,9 +430,8 @@ describe('useGeminiStream', () => {
       toolCall2ResponseParts,
     ]);
     expect(localMockSendMessageStream).toHaveBeenCalledWith(
-      expect.anything(),
       expectedMergedResponse,
-      expect.anything(),
+      expect.any(AbortSignal),
     );
   });
 });
diff --git a/packages/cli/src/ui/hooks/useGeminiStream.ts b/packages/cli/src/ui/hooks/useGeminiStream.ts
index 423f3489..284709cf 100644
--- a/packages/cli/src/ui/hooks/useGeminiStream.ts
+++ b/packages/cli/src/ui/hooks/useGeminiStream.ts
@@ -17,7 +17,6 @@ import {
   Config,
   MessageSenderType,
   ToolCallRequestInfo,
-  GeminiChat,
 } from '@gemini-code/core';
 import { type PartListUnion } from '@google/genai';
 import {
@@ -76,7 +75,6 @@ export const useGeminiStream = (
 ) => {
   const [initError, setInitError] = useState<string | null>(null);
   const abortControllerRef = useRef<AbortController | null>(null);
-  const chatSessionRef = useRef<GeminiChat | null>(null);
   const geminiClientRef = useRef<GeminiClient | null>(null);
   const [isResponding, setIsResponding] = useState<boolean>(false);
   const [pendingHistoryItemRef, setPendingHistoryItem] =
@@ -256,31 +254,6 @@ export const useGeminiStream = (
     ],
   );
 
-  const ensureChatSession = useCallback(async (): Promise<{
-    client: GeminiClient | null;
-    chat: GeminiChat | null;
-  }> => {
-    const currentClient = geminiClientRef.current;
-    if (!currentClient) {
-      const errorMsg = 'Gemini client is not available.';
-      setInitError(errorMsg);
-      addItem({ type: MessageType.ERROR, text: errorMsg }, Date.now());
-      return { client: null, chat: null };
-    }
-
-    if (!chatSessionRef.current) {
-      try {
-        chatSessionRef.current = await currentClient.startChat();
-      } catch (err: unknown) {
-        const errorMsg = `Failed to start chat: ${getErrorMessage(err)}`;
-        setInitError(errorMsg);
-        addItem({ type: MessageType.ERROR, text: errorMsg }, Date.now());
-        return { client: currentClient, chat: null };
-      }
-    }
-    return { client: currentClient, chat: chatSessionRef.current };
-  }, [addItem]);
-
   // --- Stream Event Handlers ---
 
   const handleContentEvent = useCallback(
@@ -444,9 +417,12 @@ export const useGeminiStream = (
         return;
       }
 
-      const { client, chat } = await ensureChatSession();
+      const client = geminiClientRef.current;
 
-      if (!client || !chat) {
+      if (!client) {
+        const errorMsg = 'Gemini client is not available.';
+        setInitError(errorMsg);
+        addItem({ type: MessageType.ERROR, text: errorMsg }, Date.now());
         return;
       }
 
@@ -454,7 +430,7 @@ export const useGeminiStream = (
       setInitError(null);
 
       try {
-        const stream = client.sendMessageStream(chat, queryToSend, abortSignal);
+        const stream = client.sendMessageStream(queryToSend, abortSignal);
         const processingStatus = await processGeminiStreamEvents(
           stream,
           userMessageTimestamp,
@@ -487,7 +463,6 @@ export const useGeminiStream = (
       streamingState,
       setShowHelp,
       prepareQueryForGemini,
-      ensureChatSession,
       processGeminiStreamEvents,
       pendingHistoryItemRef,
       addItem,
diff --git a/packages/core/src/config/config.test.ts b/packages/core/src/config/config.test.ts
index c3c46659..9b4b2664 100644
--- a/packages/core/src/config/config.test.ts
+++ b/packages/core/src/config/config.test.ts
@@ -35,6 +35,7 @@ vi.mock('../tools/memoryTool', () => ({
   setGeminiMdFilename: vi.fn(),
   getCurrentGeminiMdFilename: vi.fn(() => 'GEMINI.md'), // Mock the original filename
   DEFAULT_CONTEXT_FILENAME: 'GEMINI.md',
+  GEMINI_CONFIG_DIR: '.gemini',
 }));
 
 describe('Server Config (config.ts)', () => {
diff --git a/packages/core/src/core/client.ts b/packages/core/src/core/client.ts
index 732126cb..fcad1ef0 100644
--- a/packages/core/src/core/client.ts
+++ b/packages/core/src/core/client.ts
@@ -27,6 +27,7 @@ import { GeminiChat } from './geminiChat.js';
 import { retryWithBackoff } from '../utils/retry.js';
 
 export class GeminiClient {
+  private chat: Promise<GeminiChat>;
   private client: GoogleGenAI;
   private model: string;
   private generateContentConfig: GenerateContentConfig = {
@@ -50,6 +51,11 @@ export class GeminiClient {
       },
     });
     this.model = config.getModel();
+    this.chat = this.startChat();
+  }
+
+  getChat(): Promise<GeminiChat> {
+    return this.chat;
   }
 
   private async getEnvironment(): Promise<Part[]> {
@@ -114,12 +120,12 @@ export class GeminiClient {
     return initialParts;
   }
 
-  async startChat(): Promise<GeminiChat> {
+  private async startChat(extraHistory?: Content[]): Promise<GeminiChat> {
     const envParts = await this.getEnvironment();
     const toolRegistry = await this.config.getToolRegistry();
     const toolDeclarations = toolRegistry.getFunctionDeclarations();
     const tools: Tool[] = [{ functionDeclarations: toolDeclarations }];
-    const history: Content[] = [
+    const initialHistory: Content[] = [
       {
         role: 'user',
         parts: envParts,
@@ -129,6 +135,7 @@ export class GeminiClient {
         parts: [{ text: 'Got it. Thanks for the context!' }],
       },
     ];
+    const history = initialHistory.concat(extraHistory ?? []);
     try {
       const userMemory = this.config.getUserMemory();
       const systemInstruction = getCoreSystemPrompt(userMemory);
@@ -157,7 +164,6 @@ export class GeminiClient {
   }
 
   async *sendMessageStream(
-    chat: GeminiChat,
     request: PartListUnion,
     signal: AbortSignal,
     turns: number = this.MAX_TURNS,
@@ -166,6 +172,7 @@ export class GeminiClient {
       return;
     }
 
+    const chat = await this.chat;
     const turn = new Turn(chat);
     const resultStream = turn.run(request, signal);
     for await (const event of resultStream) {
@@ -175,7 +182,7 @@ export class GeminiClient {
       const nextSpeakerCheck = await checkNextSpeaker(chat, this, signal);
       if (nextSpeakerCheck?.next_speaker === 'model') {
         const nextRequest = [{ text: 'Please continue.' }];
-        yield* this.sendMessageStream(chat, nextRequest, signal, turns - 1);
+        yield* this.sendMessageStream(nextRequest, signal, turns - 1);
       }
     }
   }
diff --git a/packages/core/src/tools/tool-registry.ts b/packages/core/src/tools/tool-registry.ts
index 21aec687..12aa1a83 100644
--- a/packages/core/src/tools/tool-registry.ts
+++ b/packages/core/src/tools/tool-registry.ts
@@ -56,10 +56,10 @@ Signal: Signal number or \`(none)\` if no signal was received.
     let stdout = '';
     let stderr = '';
     child.stdout.on('data', (data) => {
-      stdout += data.toString();
+      stdout += data?.toString();
     });
     child.stderr.on('data', (data) => {
-      stderr += data.toString();
+      stderr += data?.toString();
     });
     let error: Error | null = null;
     child.on('error', (err: Error) => {