diff --git a/README.md b/README.md
index 9987d3b..7c9a0e5 100644
--- a/README.md
+++ b/README.md
@@ -44,17 +44,21 @@ planeteer list
 1. **Clarify** — Describe your project in natural language. Copilot asks clarifying questions until the scope is clear.
 2. **Breakdown** — Copilot generates a work breakdown structure: tasks with descriptions, acceptance criteria, and dependencies.
 3. **Refine** — Navigate the task tree, edit details, or type refinement requests (e.g., "split the auth task into login and signup"). Press `s` to save, `x` to execute.
-4. **Execute** — Tasks are dispatched to Copilot agents in parallel batches that respect the dependency graph. Progress is shown in real time.
+4. **Execute** — Tasks are dispatched to Copilot agents in parallel batches that respect the dependency graph. Progress is shown in real time. Press `e` during execution to view the session event log, which displays granular feedback including tool executions, progress updates, token usage, and error messages.
 
 ### Keyboard Shortcuts
 
 | Key | Action |
 |-----|--------|
 | `↑` `↓` | Navigate task list |
+| `←` `→` | Switch batch (execute screen) |
 | `⏎` | Submit input / proceed to next screen |
 | `Esc` | Go back |
 | `s` | Save plan (refine screen) |
 | `x` | Start execution (refine/execute screen) |
+| `r` | Retry failed tasks (execute screen) |
+| `e` | Toggle session event log (execute screen) |
+| `z` | Export summary to markdown (execute screen) |
 | `q` | Quit |
 
 ## Development
@@ -157,6 +161,25 @@ Plans are saved to `.planeteer/` in the current working directory:
 - `<plan-id>.json` — Machine-readable plan (used by the app)
 - `<plan-id>.md` — Human-readable Markdown export
 
+## Features
+
+### Real-Time Session Event Monitoring
+
+During task execution, Planeteer subscribes to session events from the Copilot SDK, providing granular visibility into what the AI agents are doing:
+
+- **Tool Executions**: See when tools (bash, file operations, etc.) start and complete
+- **Progress Updates**: View real-time progress messages from agents
+- **Token Usage**: Monitor input/output tokens and associated costs per task
+- **Error Details**: Get actionable error messages when tasks fail
+
+**How to use:**
+1. Start task execution with `x`
+2. Press `e` to toggle the event log panel
+3. The log shows the most recent 8 events with timestamps, task IDs, and messages
+4. Error events are highlighted in red for quick identification
+
+This feature leverages the Copilot SDK's `session.on()` event API to capture events like `tool.execution_start`, `tool.execution_progress`, `tool.execution_complete`, and `session.error`, providing transparency and debugging insights into agent behavior.
+
 ## Project Structure
 
 ```
diff --git a/src/screens/execute.tsx b/src/screens/execute.tsx
index 2302ff1..0e19984 100644
--- a/src/screens/execute.tsx
+++ b/src/screens/execute.tsx
@@ -3,6 +3,7 @@ import { Box, Text, useInput } from 'ink';
 import type { Plan, Task } from '../models/plan.js';
 import { executePlan } from '../services/executor.js';
 import type { ExecutionOptions, ExecutionHandle } from '../services/executor.js';
+import type { SessionEventData } from '../services/copilot.js';
 import { savePlan, summarizePlan } from '../services/persistence.js';
 import { computeBatches } from '../utils/dependency-graph.js';
 import Spinner from '../components/spinner.js';
@@ -15,6 +16,14 @@ interface ExecuteScreenProps {
   onBack: () => void;
 }
 
+interface DisplayEvent {
+  taskId: string;
+  type: string;
+  timestamp: string;
+  message: string;
+  isError: boolean;
+}
+
 const STATUS_ICON: Record<string, string> = {
   pending: '○',
   in_progress: '◉',
@@ -29,6 +38,50 @@ const STATUS_COLOR: Record<string, string> = {
   failed: 'red',
 };
 
+// Helper to format session events for display
+function formatSessionEvent(taskId: string, event: SessionEventData): DisplayEvent {
+  const time = new Date(event.timestamp).toLocaleTimeString();
+  let message = '';
+  let isError = false;
+
+  switch (event.type) {
+    case 'tool.execution_start':
+      message = `Tool started: ${(event.data as { toolName?: string }).toolName || 'unknown'}`;
+      break;
+    case 'tool.execution_progress':
+      message = `Progress: ${(event.data as { progressMessage?: string }).progressMessage || '...'}`;
+      break;
+    case 'tool.execution_complete':
+      const completionData = event.data as { success?: boolean; toolName?: string; error?: { message?: string } };
+      if (completionData.success === false) {
+        message = `Tool failed: ${completionData.error?.message || 'unknown error'}`;
+        isError = true;
+      } else {
+        message = `Tool completed successfully`;
+      }
+      break;
+    case 'session.error':
+      message = `Error: ${(event.data as { message?: string }).message || 'unknown error'}`;
+      isError = true;
+      break;
+    case 'assistant.usage':
+      const usage = event.data as { inputTokens?: number; outputTokens?: number; model?: string };
+      message = `Token usage — Model: ${usage.model || 'unknown'}, In: ${usage.inputTokens || 0}, Out: ${usage.outputTokens || 0}`;
+      break;
+    default:
+      // Show other events with minimal formatting
+      message = event.type;
+  }
+
+  return {
+    taskId,
+    type: event.type,
+    timestamp: time,
+    message,
+    isError,
+  };
+}
+
 export default function ExecuteScreen({
   plan,
   codebaseContext,
@@ -46,6 +99,8 @@ export default function ExecuteScreen({
   const [runCount, setRunCount] = useState(0); // incremented to re-trigger execution
   const execHandleRef = useRef<ExecutionHandle | null>(null);
   const [summarized, setSummarized] = useState('');
+  const [eventLog, setEventLog] = useState<DisplayEvent[]>([]);
+  const [showEventLog, setShowEventLog] = useState(false);
 
   const { batches } = computeBatches(plan.tasks);
   // Total display batches: init batch (index 0) + real batches
@@ -110,6 +165,10 @@ export default function ExecuteScreen({
         setTimeout(() => setSummarized(''), 3000);
       });
     }
+    // Toggle event log
+    if (ch === 'e' && started) {
+      setShowEventLog((prev) => !prev);
+    }
     if (key.leftArrow) {
       setViewBatchIndex((i) => Math.max(0, i - 1));
       setSelectedTaskIndex(0);
@@ -195,6 +254,14 @@ export default function ExecuteScreen({
         }
         // Otherwise stay on execute screen — user can press 'r' to retry
       },
+      onSessionEvent: (taskId, event) => {
+        const displayEvent = formatSessionEvent(taskId, event);
+        // Keep only the most recent 100 events to prevent unbounded memory growth
+        setEventLog((prev) => {
+          const updated = [...prev, displayEvent];
+          return updated.length > 100 ? updated.slice(-100) : updated;
+        });
+      },
     }, execOptions);
 
     execHandleRef.current = handle;
@@ -401,17 +468,55 @@ export default function ExecuteScreen({
         </Box>
       )}
 
+      {/* Event Log */}
+      {showEventLog && eventLog.length > 0 && (
+        <Box flexDirection="column" marginBottom={1} borderStyle="single" borderColor="cyan" paddingX={1}>
+          <Box marginBottom={0}>
+            <Text color="cyan" bold>Session Event Log</Text>
+            <Text color="gray"> ({eventLog.length} events)</Text>
+          </Box>
+          {(() => {
+            const maxEvents = 8;
+            const visible = eventLog.slice(-maxEvents);
+            const truncated = eventLog.length > maxEvents;
+            return (
+              <>
+                {truncated && (
+                  <Text color="gray" dimColor>··· {eventLog.length - maxEvents} earlier events ···</Text>
+                )}
+                {visible.map((evt, i) => (
+                  <Box key={i}>
+                    <Text color="gray">[{evt.timestamp}] </Text>
+                    <Text color="cyan">{evt.taskId}: </Text>
+                    <Text color={evt.isError ? 'red' : 'white'}>{evt.message}</Text>
+                  </Box>
+                ))}
+              </>
+            );
+          })()}
+        </Box>
+      )}
+
+      {/* Event log hint */}
+      {started && !showEventLog && eventLog.length > 0 && (
+        <Box marginBottom={1}>
+          <Text color="cyan">Press </Text>
+          <Text color="green" bold>e</Text>
+          <Text color="cyan"> to view session event log ({eventLog.length} events)</Text>
+        </Box>
+      )}
+
       <StatusBar
         screen="Execute"
         hint={
           executing && failedCount > 0
-            ? '←→: switch batch  ↑↓: select task  r: retry task  ⏳ executing...'
+            ? '←→: switch batch  ↑↓: select task  r: retry task  e: events  ⏳ executing...'
             : executing
-              ? '←→: switch batch  ↑↓: select task  ⏳ executing...'
+              ? '←→: switch batch  ↑↓: select task  e: events  ⏳ executing...'
               : started && failedCount > 0
-                ? '←→: switch batch  ↑↓: select task  r: retry  z: summarize  esc: back'
+                ? '←→: switch batch  ↑↓: select task  r: retry  e: events  z: summarize  esc: back'
                 : started
-                  ? '←→: switch batch  ↑↓: select task  z: summarize  esc: back'
+                  ? '←→: switch batch  ↑↓: select task  e: events  z: summarize  esc: back'
                   : 'x: start  esc: back'
         }
       />
diff --git a/src/services/copilot.test.ts b/src/services/copilot.test.ts
new file mode 100644
index 0000000..1c312b9
--- /dev/null
+++ b/src/services/copilot.test.ts
@@ -0,0 +1,60 @@
+import { describe, it, expect, vi } from 'vitest';
+import type { SessionEventData } from './copilot.js';
+
+describe('SessionEventData', () => {
+  it('should have correct type structure', () => {
+    const mockEvent: SessionEventData = {
+      type: 'tool.execution_start',
+      timestamp: new Date().toISOString(),
+      data: { toolName: 'test-tool' },
+    };
+
+    expect(mockEvent.type).toBe('tool.execution_start');
+    expect(mockEvent.timestamp).toBeDefined();
+    expect(mockEvent.data).toBeDefined();
+  });
+
+  it('should handle tool.execution_complete events', () => {
+    const mockEvent: SessionEventData = {
+      type: 'tool.execution_complete',
+      timestamp: new Date().toISOString(),
+      data: {
+        toolCallId: 'test-123',
+        success: true,
+        result: { content: 'Task completed' },
+      },
+    };
+
+    expect(mockEvent.type).toBe('tool.execution_complete');
+    expect(mockEvent.data).toHaveProperty('success');
+  });
+
+  it('should handle session.error events', () => {
+    const mockEvent: SessionEventData = {
+      type: 'session.error',
+      timestamp: new Date().toISOString(),
+      data: {
+        errorType: 'timeout',
+        message: 'Request timed out',
+      },
+    };
+
+    expect(mockEvent.type).toBe('session.error');
+    expect((mockEvent.data as { message: string }).message).toBe('Request timed out');
+  });
+
+  it('should handle assistant.usage events', () => {
+    const mockEvent: SessionEventData = {
+      type: 'assistant.usage',
+      timestamp: new Date().toISOString(),
+      data: {
+        model: 'claude-sonnet-4',
+        inputTokens: 100,
+        outputTokens: 50,
+      },
+    };
+
+    expect(mockEvent.type).toBe('assistant.usage');
+    expect((mockEvent.data as { inputTokens: number }).inputTokens).toBe(100);
+  });
+});
diff --git a/src/services/copilot.ts b/src/services/copilot.ts
index b691e58..5297078 100644
--- a/src/services/copilot.ts
+++ b/src/services/copilot.ts
@@ -104,10 +104,17 @@ export async function stopClient(): Promise<void> {
   }
 }
 
+export interface SessionEventData {
+  type: string;
+  timestamp: string;
+  data: unknown;
+}
+
 export interface StreamCallbacks {
   onDelta: (text: string) => void;
   onDone: (fullText: string) => void;
   onError: (error: Error) => void;
+  onSessionEvent?: (event: SessionEventData) => void;
 }
 
 export async function sendPrompt(
@@ -137,6 +144,20 @@ export async function sendPrompt(
   let fullText = '';
   let settled = false;
 
+  // Subscribe to all session events if callback provided.
+  // We capture all events rather than specific types to ensure comprehensive monitoring
+  // of SDK behavior (tool executions, progress updates, token usage, errors, etc.).
+  // The UI layer filters and formats events for display.
+  if (callbacks.onSessionEvent) {
+    session.on((event) => {
+      callbacks.onSessionEvent?.({
+        type: event.type,
+        timestamp: event.timestamp,
+        data: event.data,
+      });
+    });
+  }
+
   session.on('assistant.message_delta', (event: { data: { deltaContent: string } }) => {
     fullText += event.data.deltaContent;
     callbacks.onDelta(event.data.deltaContent);
@@ -176,10 +197,15 @@ export async function sendPrompt(
 export async function sendPromptSync(
   systemPrompt: string,
   messages: ChatMessage[],
-  options?: { timeoutMs?: number; onDelta?: (delta: string, fullText: string) => void },
+  options?: { 
+    timeoutMs?: number; 
+    onDelta?: (delta: string, fullText: string) => void;
+    onSessionEvent?: (event: SessionEventData) => void;
+  },
 ): Promise<string> {
   const idleTimeoutMs = options?.timeoutMs ?? 120_000;
   const onDelta = options?.onDelta;
+  const onSessionEvent = options?.onSessionEvent;
 
   return new Promise((resolve, reject) => {
     let settled = false;
@@ -235,6 +261,7 @@ export async function sendPromptSync(
           reject(err);
         }
       },
+      onSessionEvent,
     });
   });
 }
diff --git a/src/services/executor.test.ts b/src/services/executor.test.ts
new file mode 100644
index 0000000..e56974d
--- /dev/null
+++ b/src/services/executor.test.ts
@@ -0,0 +1,58 @@
+import { describe, it, expect, vi } from 'vitest';
+import type { ExecutionCallbacks } from './executor.js';
+import type { SessionEventData } from './copilot.js';
+
+describe('ExecutionCallbacks with session events', () => {
+  it('should define onSessionEvent callback', () => {
+    const mockCallback: ExecutionCallbacks = {
+      onTaskStart: vi.fn(),
+      onTaskDelta: vi.fn(),
+      onTaskDone: vi.fn(),
+      onTaskFailed: vi.fn(),
+      onBatchComplete: vi.fn(),
+      onAllDone: vi.fn(),
+      onSessionEvent: vi.fn(),
+    };
+
+    expect(mockCallback.onSessionEvent).toBeDefined();
+    expect(typeof mockCallback.onSessionEvent).toBe('function');
+  });
+
+  it('should call onSessionEvent with taskId and event data', () => {
+    const onSessionEvent = vi.fn();
+    
+    const mockEvent: SessionEventData = {
+      type: 'tool.execution_start',
+      timestamp: new Date().toISOString(),
+      data: { toolName: 'bash' },
+    };
+
+    onSessionEvent('task-1', mockEvent);
+
+    expect(onSessionEvent).toHaveBeenCalledWith('task-1', mockEvent);
+    expect(onSessionEvent).toHaveBeenCalledTimes(1);
+  });
+
+  it('should handle multiple session events for different tasks', () => {
+    const onSessionEvent = vi.fn();
+    
+    const event1: SessionEventData = {
+      type: 'tool.execution_start',
+      timestamp: new Date().toISOString(),
+      data: { toolName: 'bash' },
+    };
+
+    const event2: SessionEventData = {
+      type: 'tool.execution_complete',
+      timestamp: new Date().toISOString(),
+      data: { success: true },
+    };
+
+    onSessionEvent('task-1', event1);
+    onSessionEvent('task-2', event2);
+
+    expect(onSessionEvent).toHaveBeenCalledTimes(2);
+    expect(onSessionEvent).toHaveBeenNthCalledWith(1, 'task-1', event1);
+    expect(onSessionEvent).toHaveBeenNthCalledWith(2, 'task-2', event2);
+  });
+});
diff --git a/src/services/executor.ts b/src/services/executor.ts
index 1edf492..36b046a 100644
--- a/src/services/executor.ts
+++ b/src/services/executor.ts
@@ -1,5 +1,5 @@
 import type { Plan, Task } from '../models/plan.js';
-import { sendPromptSync } from './copilot.js';
+import { sendPromptSync, type SessionEventData } from './copilot.js';
 import { getReadyTasks } from '../utils/dependency-graph.js';
 
 export interface ExecutionCallbacks {
@@ -9,6 +9,7 @@ export interface ExecutionCallbacks {
   onTaskFailed: (taskId: string, error: string) => void;
   onBatchComplete: (batchIndex: number) => void;
   onAllDone: (plan: Plan) => void;
+  onSessionEvent?: (taskId: string, event: SessionEventData) => void;
 }
 
 function buildTaskPrompt(task: Task, plan: Plan, codebaseContext?: string): string {
@@ -112,6 +113,9 @@ export function executePlan(
         onDelta: (delta, fullText) => {
           callbacks.onTaskDelta(task.id, delta, fullText);
         },
+        onSessionEvent: callbacks.onSessionEvent ? (event) => {
+          callbacks.onSessionEvent!(task.id, event);
+        } : undefined,
       });
       taskInPlan.status = 'done';
       taskInPlan.agentResult = result;
@@ -180,6 +184,9 @@ export function executePlan(
           onDelta: (delta, fullText) => {
             callbacks.onTaskDelta(INIT_TASK_ID, delta, fullText);
           },
+          onSessionEvent: callbacks.onSessionEvent ? (event) => {
+            callbacks.onSessionEvent!(INIT_TASK_ID, event);
+          } : undefined,
         });
         callbacks.onTaskDone(INIT_TASK_ID, initResult);
       } catch (err) {