diff --git a/classes/logger.ts b/classes/logger.ts
index 3e726c6..5123310 100644
--- a/classes/logger.ts
+++ b/classes/logger.ts
@@ -14,6 +14,17 @@ export interface LogEvent {
   timestamp: string;
 }
 
+export type ToolCallStatus = "running" | "completed";
+
+export interface ToolCallInfo {
+  callId: string;
+  name: string;
+  args: string;
+  status: ToolCallStatus;
+  startedAt: number;
+  duration?: number;
+}
+
 export class Logger extends EventEmitter {
   private level: LogLevel;
   private color: boolean;
@@ -76,8 +87,26 @@ export class Logger extends EventEmitter {
     this.log(message, LogLevel.DEBUG);
   }
 
-  incrementToolCalls() {
-    this.emit("toolCall");
+  toolCallStarted(callId: string, name: string, args: string) {
+    const info: ToolCallInfo = {
+      callId,
+      name,
+      args,
+      status: "running",
+      startedAt: Date.now(),
+    };
+    this.emit("toolCallUpdate", info);
+  }
+
+  toolCallCompleted(callId: string, name: string) {
+    const info: ToolCallInfo = {
+      callId,
+      name,
+      args: "",
+      status: "completed",
+      startedAt: 0,
+    };
+    this.emit("toolCallUpdate", info);
   }
 
   onLog(callback: (event: LogEvent) => void) {
@@ -85,8 +114,8 @@ export class Logger extends EventEmitter {
     return () => this.off("log", callback);
   }
 
-  onToolCall(callback: () => void) {
-    this.on("toolCall", callback);
-    return () => this.off("toolCall", callback);
+  onToolCallUpdate(callback: (info: ToolCallInfo) => void) {
+    this.on("toolCallUpdate", callback);
+    return () => this.off("toolCallUpdate", callback);
   }
 }
diff --git a/components/App.tsx b/components/App.tsx
index 1e1320e..d930c4e 100644
--- a/components/App.tsx
+++ b/components/App.tsx
@@ -2,7 +2,7 @@ import { useState, useEffect, useCallback, useRef, useMemo } from "react";
 import { Box, useApp, useStdout } from "ink";
 import type { MCPServerStreamableHttp } from "@openai/agents";
 import type { GeneralAgent } from "../agents/general.js";
-import type { Logger, LogEvent } from "../classes/logger.js";
+import type { Logger, LogEvent, ToolCallInfo } from "../classes/logger.js";
 import type { Config } from "../classes/config.js";
 import chalk from "chalk";
 import { renderMarkdown } from "../utils/markdown.js";
@@ -45,7 +45,8 @@ export function App({
   ]);
   const [streamingText, setStreamingText] = useState("");
   const [isStreaming, setIsStreaming] = useState(false);
-  const [toolCallCount, setToolCallCount] = useState(0);
+  const [toolCalls, setToolCalls] = useState<ToolCallInfo[]>([]);
+  const toolCallsRef = useRef<ToolCallInfo[]>([]);
   const [startTime, setStartTime] = useState<number | null>(null);
   const processingRef = useRef(false);
   const queueRef = useRef<string[]>([]);
@@ -127,8 +128,26 @@ export function App({
       ]);
     });
 
-    const unsubTool = logger.onToolCall(() => {
-      setToolCallCount((prev) => prev + 1);
+    const unsubTool = logger.onToolCallUpdate((info: ToolCallInfo) => {
+      setToolCalls((prev) => {
+        let next: ToolCallInfo[];
+        if (info.status === "running") {
+          next = [...prev, info];
+        } else {
+          // Mark existing call as completed
+          next = prev.map((tc) =>
+            tc.callId === info.callId
+              ? {
+                  ...tc,
+                  status: "completed" as const,
+                  duration: Date.now() - tc.startedAt,
+                }
+              : tc,
+          );
+        }
+        toolCallsRef.current = next;
+        return next;
+      });
     });
 
     return () => {
@@ -152,7 +171,8 @@ export function App({
 
       setIsStreaming(true);
       setStreamingText("");
-      setToolCallCount(0);
+      setToolCalls([]);
+      toolCallsRef.current = [];
       setStartTime(Date.now());
 
       const abort = new AbortController();
@@ -160,15 +180,35 @@ export function App({
 
       try {
         const stream = await agent.chat(input, [mcpServer]);
-        const textStream = stream.toTextStream({
-          compatibleWithNodeStreams: true,
-        });
 
         let accumulated = "";
-        for await (const chunk of textStream) {
+        for await (const event of stream) {
           if (abort.signal.aborted) break;
-          accumulated += chunk;
-          setStreamingText(accumulated);
+          if (
+            event.type === "raw_model_stream_event" &&
+            event.data.type === "output_text_delta"
+          ) {
+            accumulated += (event.data as { delta: string }).delta;
+            setStreamingText(accumulated);
+          } else if (event.type === "run_item_stream_event") {
+            const raw = event.item?.rawItem as {
+              name?: string;
+              callId?: string;
+              arguments?: string;
+            };
+            if (event.name === "tool_called") {
+              logger.toolCallStarted(
+                raw?.callId || "",
+                raw?.name || "unknown",
+                raw?.arguments || "",
+              );
+            } else if (event.name === "tool_output") {
+              logger.toolCallCompleted(
+                raw?.callId || "",
+                raw?.name || "unknown",
+              );
+            }
+          }
         }
 
         if (abort.signal.aborted) {
@@ -213,6 +253,7 @@ export function App({
             content,
             rendered: renderMarkdown(content),
             timestamp: logger.getTimestamp(),
+            toolCalls: toolCallsRef.current,
           },
         ]);
       } catch (err) {
@@ -231,7 +272,8 @@ export function App({
         setIsStreaming(false);
         setStreamingText("");
         setStartTime(null);
-        setToolCallCount(0);
+        setToolCalls([]);
+        toolCallsRef.current = [];
       }
     },
     [agent, mcpServer, logger],
@@ -300,7 +342,7 @@ export function App({
         messages={messages}
         streamingText={streamingText}
         isStreaming={isStreaming}
-        toolCallCount={toolCallCount}
+        toolCalls={toolCalls}
         startTime={startTime}
         scrollX={scrollX}
         scrollY={scrollY}
diff --git a/components/Message.tsx b/components/Message.tsx
index 93e1160..75317a4 100644
--- a/components/Message.tsx
+++ b/components/Message.tsx
@@ -9,6 +9,7 @@ export interface MessageData {
   content: string;
   rendered: string;
   timestamp: string;
+  toolCalls?: import("../classes/logger.js").ToolCallInfo[];
 }
 
 interface MessageProps extends MessageData {
diff --git a/components/MessageArea.tsx b/components/MessageArea.tsx
index 0d5ac3d..db77f3e 100644
--- a/components/MessageArea.tsx
+++ b/components/MessageArea.tsx
@@ -2,6 +2,7 @@ import { Box, Static, Text } from "ink";
 import type { BoxStyle } from "cli-boxes";
 import Spinner from "ink-spinner";
 import type { MessageData } from "./Message.js";
+import type { ToolCallInfo } from "../classes/logger.js";
 import { renderMarkdown, applyHorizontalScroll } from "../utils/markdown.js";
 
 const dashedBorder: BoxStyle = {
@@ -15,11 +16,42 @@ const dashedBorder: BoxStyle = {
   left: "╎",
 };
 
+function ToolCallTree({ toolCalls }: { toolCalls: ToolCallInfo[] }) {
+  if (toolCalls.length === 0) return null;
+  return (
+    <Box flexDirection="column">
+      <Text dimColor>🛠️ Tool calls:</Text>
+      <Box flexDirection="column" marginLeft={2}>
+        {toolCalls.map((tc, i) => {
+          const isLast = i === toolCalls.length - 1;
+          const prefix = isLast ? "└─" : "├─";
+          const truncatedArgs =
+            tc.args.length > 80 ? tc.args.slice(0, 80) + "…" : tc.args;
+          return (
+            <Box key={tc.callId || i} flexDirection="column">
+              {tc.status === "running" ? (
+                <Text color="yellow">
+                  {prefix} ⏳ {tc.name}({truncatedArgs})
+                </Text>
+              ) : (
+                <Text color="green">
+                  {prefix} ✓ {tc.name}({truncatedArgs}) (
+                  {(tc.duration! / 1000).toFixed(1)}s)
+                </Text>
+              )}
+            </Box>
+          );
+        })}
+      </Box>
+    </Box>
+  );
+}
+
 interface MessageAreaProps {
   messages: MessageData[];
   streamingText: string;
   isStreaming: boolean;
-  toolCallCount: number;
+  toolCalls: ToolCallInfo[];
   startTime: number | null;
   scrollX: number;
   scrollY: number;
@@ -33,7 +65,7 @@ export function MessageArea({
   messages,
   streamingText,
   isStreaming,
-  toolCallCount,
+  toolCalls,
   startTime,
   scrollX,
   scrollY,
@@ -62,6 +94,11 @@ export function MessageArea({
         {(msg, i) => (
           <Box key={`msg-${i}`} flexDirection="column" marginBottom={1}>
             <Text dimColor>{msg.timestamp}</Text>
+            {msg.toolCalls && msg.toolCalls.length > 0 && (
+              <Box marginBottom={1}>
+                <ToolCallTree toolCalls={msg.toolCalls} />
+              </Box>
+            )}
             {msg.role === "assistant" ? (
               <Text>{msg.rendered}</Text>
             ) : (
@@ -92,15 +129,18 @@ export function MessageArea({
                   Thinking...
                   {startTime &&
                     ` 🕝 ${Math.round((Date.now() - startTime) / 1000)}s`}
-                  {toolCallCount > 0 &&
-                    ` | 🛠️ ${toolCallCount} tool call${toolCallCount > 1 ? "s" : ""}`}
                   {" | "}
                 </Text>
                 <Text color="yellow" dimColor>
                   [esc] to cancel
                 </Text>
               </Box>
-              {streamingText && <Text>{renderMarkdown(streamingText)}</Text>}
+              <ToolCallTree toolCalls={toolCalls} />
+              {streamingText && (
+                <Box marginTop={toolCalls.length > 0 ? 1 : 0}>
+                  <Text>{renderMarkdown(streamingText)}</Text>
+                </Box>
+              )}
             </Box>
           )}
 
diff --git a/tests/logger.test.ts b/tests/logger.test.ts
index 318abf6..93112fd 100644
--- a/tests/logger.test.ts
+++ b/tests/logger.test.ts
@@ -137,30 +137,36 @@ describe("Logger", () => {
       logger = new Logger(config);
     });
 
-    it("should have incrementToolCalls method", () => {
-      expect(typeof logger.incrementToolCalls).toBe("function");
-      expect(() => logger.incrementToolCalls()).not.toThrow();
+    it("should have toolCallStarted and toolCallCompleted methods", () => {
+      expect(typeof logger.toolCallStarted).toBe("function");
+      expect(typeof logger.toolCallCompleted).toBe("function");
+      expect(() => logger.toolCallStarted("id1", "test", "{}")).not.toThrow();
     });
 
-    it("should emit toolCall events", () => {
-      let called = 0;
-      logger.onToolCall(() => called++);
+    it("should emit toolCallUpdate events", () => {
+      const updates: any[] = [];
+      logger.onToolCallUpdate((info: any) => updates.push(info));
 
-      logger.incrementToolCalls();
-      logger.incrementToolCalls();
+      logger.toolCallStarted("id1", "search", '{"q":"hello"}');
+      logger.toolCallCompleted("id1", "search");
 
-      expect(called).toBe(2);
+      expect(updates.length).toBe(2);
+      expect(updates[0].status).toBe("running");
+      expect(updates[0].name).toBe("search");
+      expect(updates[0].args).toBe('{"q":"hello"}');
+      expect(updates[1].status).toBe("completed");
+      expect(updates[1].callId).toBe("id1");
     });
 
     it("should allow unsubscribing from events", () => {
-      let called = 0;
-      const unsub = logger.onToolCall(() => called++);
+      const updates: any[] = [];
+      const unsub = logger.onToolCallUpdate((info: any) => updates.push(info));
 
-      logger.incrementToolCalls();
+      logger.toolCallStarted("id1", "test", "{}");
       unsub();
-      logger.incrementToolCalls();
+      logger.toolCallStarted("id2", "test2", "{}");
 
-      expect(called).toBe(1);
+      expect(updates.length).toBe(1);
     });
   });