diff --git a/src/components/journal/ErrorPopup.tsx b/src/components/journal/ErrorPopup.tsx
new file mode 100644
index 0000000..73c2558
--- /dev/null
+++ b/src/components/journal/ErrorPopup.tsx
@@ -0,0 +1,30 @@
+/**
+ * ErrorPopup — shows the full error message in a floating panel above
+ * the journal input area. Toggled by clicking the truncated error text.
+ */
+import { Component, Show } from "solid-js";
+
+interface ErrorPopupProps {
+  message: string | null;
+  show: boolean;
+  onClose: () => void;
+}
+
+export const ErrorPopup: Component<ErrorPopupProps> = (props) => {
+  return (
+    <Show when={props.show && props.message}>
+      <div class="absolute bottom-full left-2 right-2 mb-1 bg-red-50 border border-red-200 rounded shadow-lg z-50">
+        <div class="flex items-start justify-between px-2 pt-2 pb-1">
+          <p class="text-red-700 text-xs break-words">{props.message}</p>
+          <button
+            onClick={props.onClose}
+            class="text-red-400 hover:text-red-600 text-xs leading-none ml-2 shrink-0"
+            title="关闭"
+          >
+            ✕
+          </button>
+        </div>
+      </div>
+    </Show>
+  );
+};
\ No newline at end of file
diff --git a/src/components/journal/JournalInput.tsx b/src/components/journal/JournalInput.tsx
index e6304fe..516f49f 100644
--- a/src/components/journal/JournalInput.tsx
+++ b/src/components/journal/JournalInput.tsx
@@ -26,6 +26,7 @@ import { parseInput } from "./command-parser";
 import type { CompletionItem } from "./command-parser";
 import { buildCompletions } from "./command-completions";
 import { CompletionsDropdown } from "./CompletionsDropdown";
+import { ErrorPopup } from "./ErrorPopup";
 
 // ---- Component ----
 
@@ -39,6 +40,7 @@ export const JournalInput: Component = () => {
 
   const [text, setText] = createSignal("");
   const [error, setError] = createSignal<string | null>(null);
+  const [showErrorPopup, setShowErrorPopup] = createSignal(false);
   const [sending, setSending] = createSignal(false);
   const [showCompletions, setShowCompletions] = createSignal(false);
   const [selectedIdx, setSelectedIdx] = createSignal(0);
@@ -406,7 +408,13 @@ export const JournalInput: Component = () => {
 
           <div class="flex items-center justify-between px-2 pb-2">
             <Show when={error()}>
-              <p class="text-red-500 text-xs truncate max-w-[60%]">{error()}</p>
+              <button
+                onClick={() => setShowErrorPopup((v) => !v)}
+                class="text-red-500 text-xs truncate max-w-[60%] text-left hover:underline"
+                title={error() ?? undefined}
+              >
+                {error()}
+              </button>
             </Show>
             <div class="flex items-center gap-1 ml-auto">
               <button
@@ -422,6 +430,13 @@ export const JournalInput: Component = () => {
           </div>
         </Show>
       </div>
+
+      {/* Error popup */}
+      <ErrorPopup
+        message={error()}
+        show={showErrorPopup()}
+        onClose={() => setShowErrorPopup(false)}
+      />
     </div>
   );
 };