diff --git a/dashboard/components/SessionCard.js b/dashboard/components/SessionCard.js
index a6ea69d..cd7551d 100644
--- a/dashboard/components/SessionCard.js
+++ b/dashboard/components/SessionCard.js
@@ -167,6 +167,7 @@ export function SessionCard({ session, onClick, conversation, onFetchConversatio
             status=${session.status}
             onRespond=${onRespond}
             autocompleteConfig=${autocompleteConfig}
+            conversation=${conversation}
           />
         `}
         </div>
diff --git a/dashboard/components/SimpleInput.js b/dashboard/components/SimpleInput.js
index f833d04..079d552 100644
--- a/dashboard/components/SimpleInput.js
+++ b/dashboard/components/SimpleInput.js
@@ -2,7 +2,7 @@ import { html, useState, useRef, useCallback, useMemo, useEffect } from '../lib/
 import { getStatusMeta } from '../utils/status.js';
 import { getTriggerInfo as _getTriggerInfo, filteredSkills as _filteredSkills } from '../utils/autocomplete.js';
 
-export function SimpleInput({ sessionId, status, onRespond, autocompleteConfig = null }) {
+export function SimpleInput({ sessionId, status, onRespond, autocompleteConfig = null, conversation }) {
   const [text, setText] = useState('');
   const [focused, setFocused] = useState(false);
   const [sending, setSending] = useState(false);
@@ -12,8 +12,15 @@ export function SimpleInput({ sessionId, status, onRespond, autocompleteConfig =
   const [selectedIndex, setSelectedIndex] = useState(0);
   const textareaRef = useRef(null);
   const autocompleteRef = useRef(null);
+  const historyIndexRef = useRef(-1);
+  const draftRef = useRef('');
   const meta = getStatusMeta(status);
 
+  const userHistory = useMemo(
+    () => (conversation || []).filter(m => m.role === 'user').map(m => m.content),
+    [conversation]
+  );
+
   const getTriggerInfo = useCallback((value, cursorPos) => {
     return _getTriggerInfo(value, cursorPos, autocompleteConfig);
   }, [autocompleteConfig]);
@@ -100,6 +107,7 @@ export function SimpleInput({ sessionId, status, onRespond, autocompleteConfig =
       try {
         await onRespond(sessionId, text.trim(), true, 0);
         setText('');
+        historyIndexRef.current = -1;
       } catch (err) {
         setError('Failed to send message');
         console.error('SimpleInput send error:', err);
@@ -130,6 +138,7 @@ export function SimpleInput({ sessionId, status, onRespond, autocompleteConfig =
           const value = e.target.value;
           const cursorPos = e.target.selectionStart;
           setText(value);
+          historyIndexRef.current = -1;
           setTriggerInfo(getTriggerInfo(value, cursorPos));
           e.target.style.height = 'auto';
           e.target.style.height = e.target.scrollHeight + 'px';
@@ -169,6 +178,57 @@ export function SimpleInput({ sessionId, status, onRespond, autocompleteConfig =
             }
           }
 
+          // History navigation (only when autocomplete is closed)
+          if (e.key === 'ArrowUp' && !showAutocomplete &&
+              e.target.selectionStart === 0 && e.target.selectionEnd === 0 &&
+              userHistory.length > 0) {
+            e.preventDefault();
+            if (historyIndexRef.current === -1) {
+              draftRef.current = text;
+              historyIndexRef.current = userHistory.length - 1;
+            } else if (historyIndexRef.current > 0) {
+              historyIndexRef.current -= 1;
+            }
+            // Clamp if history shrank since last navigation
+            if (historyIndexRef.current >= userHistory.length) {
+              historyIndexRef.current = userHistory.length - 1;
+            }
+            const historyText = userHistory[historyIndexRef.current];
+            setText(historyText);
+            setTimeout(() => {
+              if (textareaRef.current) {
+                textareaRef.current.selectionStart = historyText.length;
+                textareaRef.current.selectionEnd = historyText.length;
+                textareaRef.current.style.height = 'auto';
+                textareaRef.current.style.height = textareaRef.current.scrollHeight + 'px';
+              }
+            }, 0);
+            return;
+          }
+
+          if (e.key === 'ArrowDown' && !showAutocomplete &&
+              historyIndexRef.current !== -1) {
+            e.preventDefault();
+            historyIndexRef.current += 1;
+            let newText;
+            if (historyIndexRef.current >= userHistory.length) {
+              historyIndexRef.current = -1;
+              newText = draftRef.current;
+            } else {
+              newText = userHistory[historyIndexRef.current];
+            }
+            setText(newText);
+            setTimeout(() => {
+              if (textareaRef.current) {
+                textareaRef.current.selectionStart = newText.length;
+                textareaRef.current.selectionEnd = newText.length;
+                textareaRef.current.style.height = 'auto';
+                textareaRef.current.style.height = textareaRef.current.scrollHeight + 'px';
+              }
+            }, 0);
+            return;
+          }
+
           // Normal Enter-to-submit (only when dropdown is closed)
           if (e.key === 'Enter' && !e.shiftKey) {
             e.preventDefault();