diff --git a/src/orchestrator/orchestrator.ts b/src/orchestrator/orchestrator.ts
index db6687f..7a0f214 100644
--- a/src/orchestrator/orchestrator.ts
+++ b/src/orchestrator/orchestrator.ts
@@ -128,9 +128,9 @@ export async function executeWithRetry(
   onRetry?: (data: { attempt: number; maxAttempts: number; error: string; nextDelayMs: number }) => void,
   delayFn: (ms: number) => Promise<void> = sleep,
 ): Promise<AgentRunResult> {
-  const maxAttempts = (task.maxRetries ?? 0) + 1
-  const baseDelay = task.retryDelayMs ?? 1000
-  const backoff = task.retryBackoff ?? 2
+  const maxAttempts = Math.max(0, task.maxRetries ?? 0) + 1
+  const baseDelay = Math.max(0, task.retryDelayMs ?? 1000)
+  const backoff = Math.max(1, task.retryBackoff ?? 2)
 
   let lastError: string = ''
 
diff --git a/tests/task-retry.test.ts b/tests/task-retry.test.ts
index 23172d1..6667388 100644
--- a/tests/task-retry.test.ts
+++ b/tests/task-retry.test.ts
@@ -275,4 +275,42 @@ describe('executeWithRetry', () => {
 
     expect(mockDelay).toHaveBeenCalledWith(30_000)  // capped
   })
+
+  it('clamps negative maxRetries to 0 (single attempt)', async () => {
+    const run = vi.fn().mockRejectedValue(new Error('fail'))
+
+    const task = createTask({
+      title: 'Negative retry',
+      description: 'test',
+      maxRetries: -5,
+    })
+    // Manually set negative value since createTask doesn't validate
+    ;(task as any).maxRetries = -5
+
+    const result = await executeWithRetry(run, task, undefined, noDelay)
+
+    expect(result.success).toBe(false)
+    expect(run).toHaveBeenCalledTimes(1)  // exactly 1 attempt, no retries
+  })
+
+  it('clamps backoff below 1 to 1 (constant delay)', async () => {
+    const run = vi.fn()
+      .mockRejectedValueOnce(new Error('error'))
+      .mockResolvedValueOnce(SUCCESS_RESULT)
+
+    const task = createTask({
+      title: 'Bad backoff',
+      description: 'test',
+      maxRetries: 1,
+      retryDelayMs: 100,
+      retryBackoff: -2,
+    })
+    ;(task as any).retryBackoff = -2
+
+    const mockDelay = vi.fn().mockResolvedValue(undefined)
+    await executeWithRetry(run, task, undefined, mockDelay)
+
+    // backoff clamped to 1, so delay = 100 * 1^0 = 100
+    expect(mockDelay).toHaveBeenCalledWith(100)
+  })
 })